GB2449113A

GB2449113A - Apparatus For Measurement Accuracy Testing Of Radiological Imaging Modalities And Networked Digital Viewing Platforms

Info

Publication number: GB2449113A
Application number: GB0709069A
Authority: GB
Inventors: Cameron Nigel Glenvi Carpenter
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-11
Filing date: 2007-05-11
Publication date: 2008-11-12
Anticipated expiration: 2027-05-11
Also published as: WO2008139167A2; GB0709069D0; WO2008139167A9; GB2449113B

Abstract

The diagnostic test tool is designed to simultaneously compare and evaluate measurement accuracy on a wide range of radiological imaging apparatus. It enables comparison of known reference values of a test object against those values generated by manufacturer software image measurement programs commonly found on diagnostic viewing facilities. The tool can compare measurement accuracy across most radiological imaging platforms including digital subtraction angiography, computed tomography, magnetic resonance imaging, radio-fluoroscopy, and newer combination scanners. These can now be collectively compared and evaluated, along with manufacturer reporting software including multi-planar reconstruction, maximum intensity projection, and curved reconstructions. The construction of its cross-sectional modules will provide a reference diameter on each constructed image and will allow distance in the z-axis to be accurately referenced. Comparison of this reference value with what is measured at the reporting platform will give a measure of compliance / non-compliance of the imaging equipment with the reference. Figure 1 shows an embodiment of the invention comprising a frame 1, vertical column 6, and sockets 8 into which can be fitted measurement tubes / reference tools as shown in figures 8, 9 etc.

Description

I

APPARATUS FOR MEASUREMENT ACCURACY TESTING OF

RADIOLOGiCAL IMAGING MODALITIES AND NETWORKED

DIGITAL VIEWING PLATFORMS

This invention relates to apparatus and methods for the systematic testing of radiological diagnostic platforms, in particular digital subtraction angiography (DSA), computed tomography (CT), and magnetic resonance imaging (MRJ) modalities. The apparatus is modular to enable it to be used to assess the accuracy of measurements made on various imaging platforms, including radio-fluoroscopic (RF), nuclear imaging (NI), and computed radiography (CR) imaging platforms, and allows assessment of images viewed on Picture Archive and Communications System (PACS) diagnostic and clinical review workstations, internct I intianet browsing stations, or teleradiography imaging facilities.

The inventor states that as a result of the successful designing, building, and testing of a prototype variant of the said volumetric measurement testing apparatus, it has become evident that measurement accuracy irregularities occur, both with minimal and maximal expressions on measurement accuracy, inferred and in accordance with variations in a range of conditions that are normally encountered in the routine acquisition of radiological image data for diagnostic and Ireatment purposes of CT and MRI referred patients.

A scientific methodology has been applied to the testing protocols to ensure that data obtained is reliable, reproducible and valid across all tested imaging platforms. This will enable Ilirther testing by other specialists to be carried out with consistency in perfonnance of the prescribed method of testing and image evaluation processes.

Hospital medical imaging equipment is required by law to be regularly monitored and tested for performance by medical physics evaluation. This is usually undertaken on a scheduled basis, and performances of each radiological imaging modality is compared against manufacturer derived modality performance figures, government defined limits of acceptability for that particular type of machine, and locally agreed levels of performance that take an overall viewpoint of the machine specification, adherence to operation within government stated levels of performance, and the objectives of the imaging department.

Conventional medical physics and manufacturer testing only evaluate image measurement testing on a 2-Dimensional basis. Since modern scanners are now almost entirely available as volumetric (3-Dimensional) imaging apparatus, medical physics testing protocols should be re-evaluated to include, in addition to the existing performance evaluation regimes, updated and complementary volumetric test tools, with standardised methods of testing and image measurement, for comprehensive evaluation of the radiology imaging machine.

The nature of these measurement(s) and method(s) of testing and image evaluation(s) are notably different to those used in conventional 2-Dimensional testing, such that conventional testing regimes and test tool phantoms used by medical physics departments have neither conceptualised, or built a successful tool design to evaluate the 3-Dimensional or volumetric nature of modem CT and MRI scanners.

Consequently, current testing methods have been unable to recognise the presence of this measurement deviance, or to quantifi the magnitude of this variability, and to further examine the conditions under which these deviances occur.

It is difficult to generalise these results to all radiological procedures as this would involve a massive undertaking to assess all types of equipment. It is nonetheless a very important step for all medical technologists to realise the limitations of the present testing regimes.

With regard to living subjects who have been referred to hospital trusts for diagnostic and treatment evaluation scans, there are difficulties in correlating images and measurement evaluations of patients who have been imaged on different scanners and radiological imaging modalities. The volumetric test tool will go a long way to alerting the clinicians as to the variations in the results that are being provided by the radiological reporting process.

If the new research that underpins this tool design is not allowed to develop, the risk continues in not addressing the possibility of diagnostic imaging errors. This is directly related to the accuracy of radiological diagnosis that provides in many cases the platform for surgical intervention, cancer staging, and detailed studies that are performed to generate detailed measurements for the construction of devices that are ultimately implanted into the body, such as stents to treat aortic aneurysms. The role of radiology is to provide the high quality images, accurate measurements, and to provide information of the morphology of the affected anatomy.

Where measurement results are not shown to be deviant, but in fact are, the resulting deployment of a tailor-made stenting device may not be as easy, and the fabricated parts may not be suited to the cross-sectional diameter and length of the diseased arterial seclions.

The inability to provide for maximally accurate measurement increases the failure rate in these devices, and increases post- procedural morbidity as a result of a number of types of endoleak.

This is where re-directed blood circulation through the aortic stent is able to find its way around the device and set up another pulsatile circulation around the device. This in time causes the diseased part of the aorta to rupture, and commonly results in the death of the patient. Its cause can be attributed to bad sealing of the sections of the device to the aortic vessel wall due to incorrect sizing, and by construction build / deployment difficulties due to incorrect diameter and length measurements.

The tool(s) may be used to confirm the compliance of accuracy of linear, non-linear, curved or otherwise, measurement software on a 3-Dimensional reference model. Current testing regimes do not account for accuracy of measurement in z-axis images and performances of manufacturer software electronic calliper measurement have not been evaluated on a volumetric basis.

The tool(s) may be configured to show up variable and marked inaccuracies in the measurements generated by the manufacturer developed reporter software.

The prototype has shown flaws in the ways in which CT and MRI interrogate image data and calculate diameter and length measurements in the reference test tool images. The results of these have been provided in appendices x-y. The invention has been devised to address the absence of z-axis measurement evaluation that exists generally for all CT and MM scanners. It also addresses the incomplete assessment of measurement of linear, non-linear, curved or otherwise, across a volume of acquired image data. As of this date, the inventor has not been able to find any relative research articles or information relating to this specific subject, in any area of enquiry, including medical journal articles from medical societies around the world.

The tool has been based on a modular approach so that it may be applied across multiple imaging modalities, so that for the first time, different imaging modalities may be compared for measurement accuracy against each other. Up until now, all testing of imaging equipment has required a different range of test tools. This tool may be effectively used to assess measurement compliance and non-compliance in each modality using 2-Dimensional and 3-Dimensional dataset images from the same image acquisition.

There is no available tool on the market that offers this possibility and as a consequence, the testing of this aspect is not current practice. The tool can also be configured to show the success and failure of manufacturer 3-Dimensional reporting software to give accurate and consistent diameter and length measurement(s) of reference tool images. These are matched against their known reference values, and marked deviations indicate where measurement errors have occurred and to what degree of effect it will have in the whole of the measurement process. The inclusion of this 3-Dimensionai imaging tool and test methods alongside the existing 2-Dimensional test regimes will establish a fully comprehensive knowledge of volumetric imaging and help scanning facilities to deliver more predictable and reliable measurement information.

The inclusion of the measurement accuracy correction module is to provide further clarification as to the existence and magnitude of errors that occur during routine use, and also to validate that measurements of good integrity are largely being provided by these radiological imaging modalities and their specialist measurement and image manipulation tool software.

The correction module is designed to address the problems encountered with image mis-registration, distortion and other hardware / software based measurement anomalies by allowing a reference matrix to be unobtrusively included and unobvious in all images of the imaged sequence. It achieves this by being incorporated into the table of the imaging modality, although is may be used in conjunction with the main imaging tool for cross-sectional measurement compliance testing. The correction module may further be used as a calibration tool for otheT described computer based platforms to further evaluate the accuracy of the manufacturer software measurement values against those provided by the reference tools inbwlt to the correction module, and those provided by the software programs.

The aim of the present invention is to overcome one or more of the disadvantages described above.

According to the first aspect of the invention, we provide; 1. Radiological image testing apparatus comprising a base frame(s),vertical column(s), tubular measuring tube(s), linear reference tool(s), measurement devices accessory base plate, tool supporting block accessory module, and specialised imaging 2-Dimensional, 3-Dimensional and z-axis testing modules, in that the base frame functions as the first point of a progressive modular imaging system that can be assembled quickly for convenience and made to function as a cross-sectional diameter and linear, curved or otherwise defined distance verification tool.

2. Apparatus as claimed in Claim 1, wherein the apparatus comprises individually configured sections to enable specific tesling of an imaging modality and subsequent image evaluation using manufacturer modality software packages, the reference value(s) of functional tools therein contained in testing modules, to provide a comparison of measurement accuracy of manufacturer software against that of the reference modules.

3. Apparatus as claimed in Claim 1, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of digital subtraction imaging apparatus (DSA) and their generated image(s).

4. Apparatus as claimed in Claim 3, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the digital subtraction angiography (DSA) reference tool(s).

5. Apparatus as claimed in Claim 1, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of computed (axial) tomography (CT) and their generated image(s).

6. Apparatus as claimed in Claim 5, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the computed tomography (CT) reference tool(s).

7. Apparatus as claimed in Claim 1, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of magnetic resonance imaging (MRI) apparatus and their generated image(s).

8. Apparatus as claimed in Claim 7, wherein said apparatus configured for testing magnetic resonance imaging (MR1) apparatus and their generated images, can be if preferred loaded into a perspex, acrylic or other suitable clear, light and non-magnetic tank enclosure, which can then be filled with water and tested according to recognised current standard MRI testing procedures.

9. Apparatus as claimed in Claims 7-8, wherein said apparatus and tool configuration can be used to compare manufacturer software measurements against that for the magnetic resonance imaging (MRI) reference tool(s).

10. Apparatus as claimed in Claim I, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of radio-fluoroscopy (RF) and their generated image(s).

11. Apparatus as claimed in Claim 10, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the radio-fluoroscopy (RF) reference tool(s).

12. Radiological image testing apparatus comprising a base frame(s), measurement devices accessory base, tool supporting block accessory module, and specialised imaging 2-Dimensional, 3-Dimensional and z-axis testing modules, in that the base frame functions as the first part of a progressive modular imaging system that can be assembled quickly for convenience and made to function as a linear, curved or otherwise defined distance verification tool.

13. Apparatus as claimed in Claim 12, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the nuclear (isotope) imaging tool(s).

14. Radiological image testing apparatus comprising a base frame(s), vertical column(s), Linear measurement tubes and specialised computed radiography (CR) imaging module(s) for the imaging of 2-Dimensional and 3-Dimensional test objects and reference radio-opaque markers, in that the base frame functions as the first point of a progressive modular imaging system that can be assembled quickly for convenience and made to function as a cross-sectional diameter and linear or otherwise defined distance verification tool(s).

15. Apparatus as claimed in Claim 14, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the computed radiography (CR) imaging tool(s).

16. Apparatus as claimed in Claims 1-15, wherein the tool can be used to verify the measurement accuracies of modality software measurement platforms, and which can be further used to compared image measurement values obtained from images transferred by networking or other image transfer processes to local or remote clinical review or diagnostic workstation facilities, whose resident software may be similar or dissimilar to manufacturer software on the originating image generation platforms.

The said images may be part of a specific study series of medical images that are transferred by Digital Communications in Medicine (DICOM) version 3 or higher, or other suitable or evolutionary standard, and the tool may be used to assess reconstruction accuracies across different network systems, architectures and software viewing / measuring platforms, such as Picture Archive and Communications System (PACS) systems. These said images may be further assessed against the tool reference values for accuracy, distortion and measurement non-conformancy.

17. Apparatus as claimed in Claims 1-16, wherein said reference values of imaging test tools may be used to test measurement accuracies of software manipulation and measurement packages utilising cross-sectional diameter(s), length (linear or other variant), using constructed, reconstructed, multi-planar reconstruction (MPR), Maximum Intensity Projection (MIP), curved reconstruction, other post-processed image manipulation, or other evolutionary software image generated using an alternative principle of construction / reconstruction.

18. Apparatus for generating measurement reference images acquired as a component part of computed tomography (CT) radiological image(s), and which serves to accurately indicate measurement parameter(s), namely length, diameter, area, volume, pixel, voxel or other preferred unit of image measurement(s).

19. Apparatus as in claim 18, wherein the apparatus may be used to compare measurements obtained from other external computerised tomography (CT) measurement methods, and by which comparison of measurement values to that given by the said apparatus will enable the determination of measurement accuracy matched against that for the said measurement reference(s) built into the apparatus.

20. Apparatus as claimed in 18, which may be used as a distance and diameter calibration tool for computerised tomography (CT) measurement programs that may be applied in addition to manufacturer measurement software programs, and which serve to provide a secondaiy means of measurement verification based upon the reference distances and diameters contained in the said apparatus.

21. Apparatus as claimed in 18, where the distance, area, volume or other preferred method of parametric calibration(s) derived from the reference markers contained therein function as reference values for a computensed graphical measurement matrix for computerised tomography (CT) that may be applied to and linked to images and image order of the series acquisition, and whereby is used to generate numerical data concerning the linear, area, volume or otherwise, measurement of area(s) of interest for comparison with similarly computer processed measurement(s) obtained by manufacturer measurement software for the particular radiological imaging modality.

22. A method of assessing accuracy of radiological imaging apparatus, comprising supporting a reference tool, suitable for an imaging technique being used, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

23. Apparatus for generating measurement reference images acquired as a component part of magnetic resonance imaging (MRI) radiological or medical image(s), and which serves to accurately indicate measurement parameter(s), namely length,, diameter, area, volume or other preferred unit of image measurement(s). C'

24. Apparatus as in claim 23, wherein the apparatus may be used to compare measurements obtained from other external magnetic resonance imaging (MRI) measurement methods, and by which comparison of measurement values to that given by the said apparatus will enable the determination of measurement accuracy matched against that for the said measurement reference(s) built into the apparatus.

25. Apparatus as claimed in 23, which may be used as a distance and diameter calibration tool for magnetic resonance imaging (MRI) measurement programs that may be applied in addition to manufacturer measurement software programs, and which serve to provide a secondary means of measurement verification based upon the reference distances and diameters contained in the said apparatus.

26. Apparatus as claimed in 23, where the distance, area, volume or other preferred method of parametric calibration(s) derived from the reference markers contained therein function as reference values for a magnetic resonance imaging (MRI) graphical measurement matrix that may be applied to and linked to images and image order of the series acquisition, and whereby is used to generate numerical data concerning the linear, area, volume or otherwise, measurement of area(s) of interest for comparison with similarly computer processed measurement(s) obtained by manufacturer measurement software for the particular radiological imaging modality.

27. A method as claimed in Claim 22, of assessing accuracy of computensed tomographic imaging apparatus (CT), comprising supporting a reference tool, suitable for computensed tomographic imaging techniques, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

28. A method as claimed in Claim 22, of assessing accuracy of magnetic resonance imaging apparatus (MR1), comprising supporting a reference tool, suitable for computerised tomographic imaging techniques, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus to obtained with at least one known measurement of the tool.

29. A method as claimed in Claim 22, of assessing accuracy of radio-fluoroscopic and subtraction imaging apparatus (DSA and RF), comprising supporting a reference tool, suitable for fluoroscopic, screen captured, digital subtraction, or digital subtraction tomographic imaging techniques, in a required position in / on the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

30. A method as claimed in Claim 22, of assessing accuracy of nuclear (isotope) imaging apparatus, comprising supporting a reference tool, suitable for scintigraphic and tomographic imaging techniques, in a required position on the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

31. A method as claimed in Claim 22, of assessing accuracy of computerised radiological imaging apparatus (CR), comprising supporting a reference tool, suitable for computerised radiographic imaging techniques, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

32. A method as claimed in Claim 22, of assessing accuracy of images transferred across digital image networks by electronic means such as teleradiology, Picture Archive and Communications System (PACS), or other suitable digital image transmission I receiver system, comprising supporting a reference tool, suitable for computerised radiographic imaging techniques, generation of reference images, in a required position in I on the above mentioned radiological imaging apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

U

33. A method(s) according to Claims 22,27 -32, whereby said radiographic imaging apparatus and test tool(s), are subjected to the prescribed methods of testing contained within the stated methods of testing, and other supportive descriptions, for each respective image modality and image viewing / evaluation platform. Derivations or modifications of said method(s) of testing, forms the basis for further testing procedure(s) or methods on the desired imaging modality, and other more complex I preferred testing procedures may be derived by combination(s) of one or more aspects from dissimilar modality test methods and procedures. These testing methods may however be subject to change according to changes in the radiographic imaging apparatus, viewing and measuring software, and optimisation of existing test method(s).

34. A method(s) according to Claims 18-21, whereby said measurement accuracy correction tool is used to generate computed tomography (CT) reference images and measurement values for diameter, length, area, volume or other parametric quantity, and which will form the basis for comparison with that of the calculated values from manufacturer measurement software packages.

35. A method(s) according to Claims 18-21, whereby the reference markings, measurement (s) matrix, reference spheres, and reference diameter disks and lines can be used to calibrate computed tomography (CT) or to be used with other computer generated measurement accuracy measurement platforms to validate or compare measurement values derived from manufacturer software measurement programs against that of the measurement correction accessory module for computed tomography (CT).

36. A method(s) according to Claims 23-26, whereby said measurement accuracy correction tool is used to generate magnetic resonance imaging (MRI) reference images and measurement values for diameter, length, area, volume or other parametric quantity, and which will form the basis for comparison with that of the calculated values from manufacturer software measurement packages.

37. A method(s) according to Claims 23-26, whereby the reference markings, measurement (s) matrix, reference spheres, and reference diameter disks and lines can be used to calibrate or to be used with other computer generated measurement accuracy measurement platforms to ii validate or compare measurement values derived from manufacturer software measurement programs against that of the measurement correction accessory module for magnetic resonance imaging (MRI).

38. According to a second aspect of the invention, there is provided an electronic and / or computerised version or representation of apparatus in accordance with the fist aspect of the invention(s).

39. According to the third aspect of the invention, there is provided apparatus for the measuring of radiological images, substantially as herein described and with reference to and / or as illustrated in the accompanying drawings.

Various examples of apparatus embodying the invention, and examples of methods of use, which may be adopted in the use of such apparatus for measurement of the said imaging modalities, will now be described by way of example only, with reference to the accompanying drawings, in conjunction with which the description which follows is to be read and in which: FIGURE 1 illustrates in a 3-Dimensional drawing a typical setup of the said base frame, locking pin assembly and vertical column(s).

FIGURES 2-3 illustrate in perspective and side elevational views respectively, a relatively fixed construction and arrangement of the said vertical column, linear vertical and horizontal measurement tool(s).

FIGURE 4 illustrates a plan view of said vertical column with scalar graduations for linear measurements, and x-axis and y-axis measurement tube retention clips.

FIGURE 5 illustrates an enlarged perspective view of the vertical column in more detail, showing the positioning of x and y axis linear measurement tools, and linear measurement scales at the edges of the vertical column.

FIGURES 6-7 illustrates in perspective and plan views respectively, the constructional design of the measurement tubes.

FIGURE 8 illustrates a double loop measurement tool placed into the vertical column..

FIGURE 9 illustrates a spiral measurement tool placed into the vertical column.

FIGURE 10 illustrates a single arc or angular measurement tool placed into the vertical column.

FIGURE 11 illustrates a four section angulated measurement tool placed into the vertical column.

FIGURE 12 illustrates further tool shapes and variation in the form of a short linear measurement tool.

FIGURE 13 illustrates a long linear measurement tool (over 20 centimetres in length).

FIGURE 14 illustrates a sinusoidal wave shaped measurement tool.

FIGURE 15 illustrates an arced or angular shaped measurement tool.

FIGURE 16 illustrates a high amplitude sinusoidal wave shaped measurement tool.

FIGURE 17 illustrates a tnmcated or spiral shaped measurement tool.

FIGURE 18 illustrates a circular shaped measurement tool.

FIGURE 19 illustrates an oval or ovoid shaped measurement tool. FIGURE 20 illustrates a triangular shaped measurement tool.

Measurement tools may be varied to account for 2-Dimensional or 3-Dimensional measurement by setting their shape to vary partially or completely in all three orthogonal planes.

FIGURE 21 illustrates the method of attachment of the measurement tube to the vertical column.

FIGURE 22 illustrates the typical construction of the body of the magnetic resonance imaging tank enclosure with two spirit bubble level indicators and adjustor feet.

FIGURE 23 illustrates the typical construction of the perspex tool enclosure or water tank in perspective view.

FIGURES 24-25 illustrates the endplate of the water tank enclosure in plan and side elevational views respectively.

FIGURE 26 illustrates a 3-Dimensional view of the design of the adjustable feet on the tank enclosure.

FIGURE 27 illustrates a 3-Dimensional view of the measurement devices accessory base plate.

FIGURE 28 illustrates a 3-Dimensional view of the tool supporting block accessory module.

FIGURE 29 illustrates a 3-Dimensional view of the accessory module for the z-axis measurement tool for the testing of computed tomography (CT) apparatus.

FIGURE 30 illustrates an axial or transverse view of the geometrical aspects of the z-axis tool for the testing of computed tomography (CT).

FIGURE 31 illustrates a sagittal view of the appearances of the cylindrical measuring rods on computed tomography (CT).

FIGURE 32 illustrates a coronal view of the appearances of the cylindrical measuring rods on computed tomography (CT).

FIGURE 33 illustrates a perspective view of the constructional design of the accessory module for measurement in nuclear (isotope) imaging (NI).

FIGURES 34-35 illustrates a perspective view of the outer steel pin-point aperture cylinder and a perspective view of the inner plastic isotope holding tube respectively.

FIGURE 36 illustrates a 3-Dimensional view of the side mounted tool section array for measurement in nuclear (isotope) imaging (NI).

FIGURE 37 illustrates a 3-Dimensional view of a two or three lined distance array for measurement in nuclear (isotope) imaging (NT).

FIGURE 38 illustrates a 3-Dimensional view of a four lined distance array for measurement in nuclear (isotope) imaging (NI).

FIGURE 39 illustrates a sagittal or coronal view of a three or four lined test tool image, with its spatial or distance relationships, used as means of testing measurement accuracy in nuclear (isotope) imaging (NI).

FIGURE 40 illustrates a plan view of an accessory module for creating computed radiography images for assessment of linear distance(s), diameter, beam delineation, sensitometric and resolution functions.

FIGURE 41 illustrates a plan view of the tubular tool accessory module for measurement testing in computed radiography (CR).

FIGURES 42-43 illustrates in perspective and plan views respectively the feature of the measurement tool retaining clips.

FIGURE 44 illustrates a plan view of the accessory module for computed radiography (CR) image measurement verifications.

FIGURE 45 illustrates a side elevational view of the accessory module for computed radiography (CR) image measurement verifications.

FIGURES 46-47 illustrate a side elevational view respectively of a combined tool configuration for the testing of nuclear (isotope) imaging and computed tomography (CT) scanners.

FIGURE 48 illustrates a coronal view of the cross-sectional (CT) correction matrix.

FiGURE 49 illustrates a coronal view of the reference disks and lines of the measurement correction accessory module for computed tomography (CT).

FIGURE 50 illustrates a sagittal view of the cross-sectional (CT) correction matrix.

FIGURE 51 illustrates a transverse or axial view of the cross-sectional (CT) correction tool.

FIGURE 52 illustrates a coronal view of the typical positioning of triangle reference points for calculation of linear distance(s).

FIGURE 53 illustrates a diagrammatic perspective view of a patient as viewed from the feet in a computed tomography (CT) scanner.

FIGURE 54 illustrates the distance relationships between measurement(s) of patient anatomical parts in different planes of viewing.

FIGURE 55 illustrates a sagittal view of the measurement accuracy correction tool for magnetic resonance imaging (MRI) and triangle reference points.

FIGURE 56 illustrates a coronal view of the measurement accuracy correction tool for magnetic resonance imaging (MRI) and triangle reference points.

FIGURE 57 illustrates an axial or transverse view of the measurement accuracy tool for magnetic resonance imaging (MR1) and triangle reference points.

The tool is designed to check the accuracy of the machine manufacturers' imaging matrices, software measurement tools, and image manipulation packages. It functions to compare a known reference value of cross-sectional diameter and length, against that measured on the modality software. The resultant values will give a measure of confidence for the particular system and setup, or may be used to demonstrate measurement compliance, degrees of measurement abnormality and conditions leading to reading variance. r:f-

The said apparatus has been constructed to provide highly accurate, reproducible, and reliable measurements of any marked, delineated or otherwise indicated linear, curvate, concenthc, eccentric or curvilinear line(s), plane(s) of interest, area(s) or volume(s) in any singularity, multiplicity or combination(s) of the aforementioned value(s), function(s) or properties of the measured object(s), to the nearest millimetre (metric), sub-division of inch (Imperial) or other approved designation of interval, distance, area or volume.

Referring now to figure 1, there is shown a verification tool comprising a base frame I to which a number of tools are connectabie. Each of the tools is described in more detail below.

The base frame I is substantially rectangular and comprises two longitudinal members 2 and which are connected to each other at their ends by two lateral members 3.

The two longitudinal members are placed in parallel and in line with each other and are spaced at their extremes and positioned squarely and securely fixed by a non-magnetic screw, clip or other sectional fastener to the lateral members 3, which are placed in-between and at the ends of the two longitudinal members 2. The longest and lateral members 2, 3 may comprise wood, perspex (RTM), acrylic or other suitably non- magnetic material.

Each of the lateral members 3 comprises at least one locating hole 4. In the present example, each of the longitudinal members comprises a plurality of locating holes 5 spaced at regular intervals along its internal face. In the present example, the locating holes 5 are spaced at 40 millimetre intervals, along the internal face.

The locating holes 4 are typically 5 millimetres in diameter and extend through the longitudinal member 2. The spacing of these holes and their diameter(s) may be modified according to the overall dimensions of the measurement tool.

The dimensions of the two longitudinal members 2 are typically 450 millimetres length by 20 millimetres by 20 millimetres square and uniform along their lengths, while the two lateral members 3 are typically 200 millimetres length by 20 millimetres by 20 millimetres at each end and also uniform along their lengths. The said sections form a base frame of 450 millimetres by 240 millimetres. It will be appreciated that the base frame 1 can be any shape and its dimensions can be selected as required.

Typically, fixing such as a brass screw or other suitable non-magnetic material may be used to connect the longitudinal 2 and lateral members 3 of the base frame I together, in the case of wooded base frame constructions, if the tool is not to be used in a water filled container, as might be required for measurements concerning magnetic resonance imaging machines.

Where the frame is intended to be immersed in a water bath, the fixings comprising nylon, aluminium alloy or other suitable material equivalents for the fixing of the perspex, acrylic, or other equivalent material base frame may be used.

Other variants or combinations may be used under discretion and practicality reasons where the said materials or other(s) provide enhanced performance, increased durability or greater mechanical stability.

One of the tools which is connectable to the base frame 1 is a vertical column 6. The vertical column 6 is mounted perpendicularly to the said base frame 1, and across the width of the base frame. The vertical column 6 is a section of typical dimensions of 240 millimetres width, 150 millimetres height and 20 millimetres thickness. Attached and continuous with its lowermost and Lateral aspects are two extensions 7 of the section that serves to interfiice with the innermost and longest facet of the longitudinal member(s) 2 of the base frame. The typical dimensions of each of the said extensions are 15 millimetres long, by 10 millimetres width, and 20 millimetres height. On the innermost or medial face of this section, and in the geometrical centre, is a 5 millimetre drilled hole that may be lined up with a preferred hole 4 on the innermost aspect of the longitudinal member(s) of the base frame 2.

An unthreaded nylon or other suitable non-magnetic material headed locking pin may then be placed into each of the two holes to allow the sections to be fixedly or releasably and / or variably secured together into the base frame.

The diameter of the pin(s) would typically be fractionally below 5 millimetres, its length 30 millimetres, whilst its head diameter 15 millimetres with a shoulder thickness of 5 millimetres.

The typical setup of said base frame I and said vertical column 6 is shown in figure 1.

The vertical column 6 comprises at least one socket 8. In the present example the / or each socket typically comprises an octagonal hole which extends substantially horizontally through the vertical column, and has a flat-face to opposite flat-face distance of 10.5 millimetres.

Where the vertical column comprises a plurality of sockets, the sockets are arranged in vertical and horizontal rows. In the present example, each alternate row is typically off-set from the one above and below by a factor of 50% of the distance between the centres of one socket to that of another either horizontally or vertically.

The choice of staggered rows is designed to increase the peripheral measurement capabilities of the tool, while a more in-line configuration may aid in more centralised and central axis I iso-centre based testing methods (figures 2-5).

The base frame I may hold one or more vertical columns 6, but generally no more than three. A clip extension 9 for attachment of a specified diameter tubular measurement reference tool is integrally incorporated into each vertical column(s) 6. The clip extension 9 is incorporated at the middle point and at the extremes of the geometrical x and y axes of each face of each vertical column (figures 2-5).

Said vertical section(s) 6 will be marked with metric graduations 12 along three edges. This will allow investigators to view the metric graduations from both sided of the vertical columns. The paint or polymer colour chosen for the vertical column should contrast with the graduations on the scales so as to maximise the reading accuracy. The paint used should be of a pennanent nature and have water resistant properties (Figures 4-5).

An x-axis or y-axis measurement tube(s) 10, 11 is receivable into the I each corresponding axis clip extension(s) 9, or I in combination with a singularity or plurality of z-axis tubes in the / or each socket 8. The / or each measuring tube comprises a formed thermoplastic, polymeric compound, silicon rubber derivative or other suitable non-magnetic, radiolucent and durable tube material.

A range of measurement tubes having various lengths and diameters may be provided, although the x-axis and y-axis measurement tubes will typically have an external diameter of 10 millimetres and an internal diameter of 8 millimetres and will serve as reference diameters.

Each measurement tube 10, ii, 12 has its cross-section typically divided into four quadrants 15 by the manufacturer extrusion method of the said material (Figures 6-7). Said quadrants 15 will divide the tube into four chambers along the length of the tube, and the dividing quadrant walls will typically be 0.5 to 3.0 millimetres thick, and will typically extend from the point where it meets the circumference of the internal diameter of the measuring tube, to a point typically 1.0 to 2.0 millimetres short of the centre point of the tube (central axis).

Each measurement tube 10, 11, 12 will at its centre contain a copper wire 16 of typically 1.0 to 3.5 millimetres diameter, which will serve as a central axis marker and the length of this will determine the length of the tube that is actually used in the measurement process.

Said copper wire 16 will extend from the centre of the base of the measuring tube and towards its other end. The wire will always lie at the centre point of the tube due to its quadrant construction. Said copper wire will have accurately notched or indicated 1 centimetre major graduations and 1 millimetre minor graduations, that may be visualised during X-radiation and magnetic resonance imaging, as larger and smaller notches, and will be of a reference length that will be a stated characteristic of the measurement tube, in addition to its tube diameters (internal and external), and its encapsulated imaging volume.

The interior of the said tube will additionally contain the oil or specified hydrogen containing medium that will be used to generate the magnetic resonance signal during Ti, T2*, T2, TI (Inversion) or other preferred magnetic resonance (radio-frequency) induced excitation / relaxation process(es) to the medium by the applied pulse sequence(s) 17 (See glossary). The chamber Will be filled and sealed by an appropriate material end plug that will seal and combine with the material of the tube wall, and will be impervious to diffusion of gases from within or air / other gas entry, or chemical decompositions.

The measurement tubes will have a singularity or plurality of lesser or greater curvatures or range of tortuosity. The range of measurement tubes at its simplest will include a single curve of shallow curvature 18 whilst others may increase in complexity by including multiple curves with high and low levels of curvature 19-30. Furthermore, the essential design feature that triggers the mis-registration of positional data information to the cross-sectional imaging modality, and that must be included in measurement tube design, is that the course of the tube from one end to another must be such that it describes a shallow or marked deviation in at least two out of three orthogonal planes, so as to be beyond the resolving power of the manufacturer provided measuring software programs. The lengths of these tubes may be variable, in addition to the variances in the cross-sectional diameter(s) of the measurement tube, but in general more deviant measurements are obtained with smaller diameter, longer length and highly tortuous tubes with multiple "antagonistic curves" that travel in one plane and then rapidly deviate by 90 degrees or less into another plane or direction across the x-axis and y-axis, and then along the z-axis which generally tends to be the distance component of the measurements.

Maximal deviance is demonstrated with a plurality of these described antagonistic curves. A. range of variations of tool shapes for illustrative purposes, placed within in the vertical columns 6 are shown in figures 8-11, while other typical variant shapes of measurement tubes are further illustrated in figures 12-29, other variations not being restrained to the shapes herein defined or a limitation in the combination(s) of said tool shapes placed in any singularity or plurality of octagonal 8 or otherwise shaped recesses on either face of said vertical column(s) 6.

Said measurement tubes will be accurately moulded, extruded or engineered into a range of prescribed bends and tortuosity, to enable the tool to perform its measurement functions. At the base of each measurement tube is a "mounting" section for location and fixing of the tube into the said vertically mounted section previously described 31.

Said mounting section 31 consists of a durable and strong thermoplastic or polymer that is moulded into a section with a head, body and base. The head consists of a larger diameter circular plate typically 3 millimetres greater than the diameter of the said attached measurement tube. The attachment of the said tube is required to be both strong and durable in its nature. On the underside of the said head section and continuous is the body which consists of an octagonal block of greatest face-to-opposite face distance of 10 millimetres. The length of the block would typically be 15 millimetres. Said mounting section would be located into the octagonal recess of the socket(s) 8 on the vertical section 6 and pushed in until contact with the underside of the head section would prevent further movement. The choice of an octagonal block 8 will provide a large range of positional variations (up to eight) available to the user at the time of setting-up of the tool (Figure 21). It will be appreciated that the shape of the locating holes may be selected as required.

Said tube length multiplied by its actual cross-sectional area will derive what will be known as the "imaging volume", and will Contain an inert oil, or other suitable material, that will not attack the composition or structure of the tube material, and Will possess a high enough level of protons (hydrogen nuclei), such that when energised by the magnetic resonance process, will return a 2:2 high enough signal so as to be easily distinguishable from its surrounding medium, typically water, air, or other hydrogen containing compound. This will serve to increase the boundary contrast between the interfaces of the test tool and the surrounding or filling medium, so that increased accuracy or reading is achieved The said oil or equivalent medium should also be of a high enough X-ray attenuation so as to offer a readable degree of contrast to the surrounding medium and the marker notches on the central wire. This will also facilitate the accuracy of reading for other X-radiation imaging modalities.

The vertical column(s) 6 may hold a singularity or plurality of measurement tubes in the locating holes on each of its faces according to the preference of the user, in any configuration afforded by the positioning of the measurement tube(s) on the sectional face, the relative diameter and length of the chosen measurement tube, and the number of vertical columns used during the testing. Use of a plurality of tubes may result in difficulties in tracking the individual tubes on the generated test images, and in the manufacturer's software to visualise singular rather than multiple objects on a given measurement platform.

In these cases the margin of error may become more significant, and may in itself offer no appreciable advantage in the outcomes of the measurement process.

The use of additional iso-centric and peripheral tool reference measurement tubes may be applied, one on each face of said vertical column(s) to assess for accuracy in the x -and y -axes across the iso-centre or centre of the imaging field. This would allow linear measurements of length across the field of view to be evaluated in conventional 2-Dimensional imaging, which is generally current testing practice. In this case, the middle of the reference measurement tube would be placed with the centre notch of the central wire at the centre of the measuring field (iso-centre), and in line with the intersection(s) of the axis lines on the faces of the said vertical column. The measurement tubes would be mounted in the retaining clips along the x-axis on one face, and along the y-axis on the other face. This would also be in line with the x-axis and y-axis positioning laser beams of the tested scanner, and would verify the accuracy of the positioning lasers on the scanner.

In the case of MRI measurement(s), the assembled said base frame, vertical column(s) and tubes (reference and measurement) are receivable in an external tool holder for final assembly prior to testing. Said external tool holder construction consists of perspex, acrylic or other transparent, strong, durable and non-magnetic materials that functions as an enclosure for the said measurement tool(s). The advantages of mounting the base frame and measurement tube(s) within a water bath and imaging using magnetic resonance are that it overcomes the problems* with Specific Absorption Rate (SAR) limitations, where due to the small amount of signal generated by the testing equipment minus the water bath, it is difficult to initiate an MRI sequence because the signal received is not strong enough to generate an image (low signal to noise ratio). Submersion in a water bath returns a much greater signal to noise value due to the high number of hydrogen nuclei in the water tank, and the scanning sequence is initiated.

A further benefit of testing in water is that it is far easier to visualise the walls of the measurement tube since they appear as low signal (dark) areas or rings surrounded by brighter fluid on the outside and brighter fluid with the walls of the measurement tubing The external tool holder 32 typically consists of formed perspex or acrylic polymer that is shaped into a flattened oval shape, and whose wall is typically 10 millimetres thickness 36. The flattened part of the said holder extends typically for 252 millimetres at its resting base from end to end before it describes a curve at each respective end that continues to reach its apex laterally to a further 50 millimetres beyond the limits of the planar sections or at the limits of the desired design parameters, to continue its curvate or curvi-linear extension in an opposite and complementary fashion to the aforementioned course where it becomes continuous with the raised or higher planar section of the holder. This forms a thick perspex rim 35 for locating with the end plate of the tank enclosure. On the upper surface and at positions at 90 degrees to one another, two non-metallic spirit levels 33 are attached in order to provide a visual means of levelling status. On its lowest surface and at each edge of the holder are screwed feet made of perspex, acrylic or other suitable non-magnetic material, to enable the unit to be levelled during use 34 (Figure 22).

Said holder may typically have a width of 362 millimetres, height of 172 millimetres and a length of 475 millimetres. At the edge of the said planar sections of the holder are arranged two 5 millimetres wide by 3 millimetres high locator ridges 37 that serve to guide the tool into the centre of the said tool holder, and run the length of the planar section to the farthest face of the enclosure. At the farthest or end of the enclosure, using the aforementioned description as a reference point, there is a transparent perspex or acrylic planar section, the end plate 38, that is continuous with the farthest margins of the said holder. 2k

The said section forms an end to the said holder and is in itself sealed and continuous with the peripheral margins with the farthest end of the holder (Figure 24-25).

At the reference end of the tool holder, and at the periphery of the holder is an expanded and circumferential section of the tank enclosure that forms a flange. The said flange is designed to extend to a point circumferentially 25 millimetres beyond the internal margins of the holder at the reference end of the enclosure, and is machined to offer as perfectly a flattened surface for application as a seal at a point 10 millimetres beyond the inner rim of the holder. At a line distance of 15 millimetres beyond the rim, and applied along the length of the flange, a series of holes 39 are drilled onto the flange with a separation of typically 60 millimetres. The diameter of said holes is typically 7 millimetres, and on the underside is embedded a threaded insert that will accept a 5 millimetre screw shank 40. The composition of the said embedded insert for the protection of the fastening screws is ideally a non-magnetic and water corrosion resistant alloy that is easily machined and has a high tensile stress.

The said measurement tool is loaded between the locator ridges 37 and is pushed to its farthest extreme. The reference end cover plate consists of transparent perspex, acrylic or other suitable material planar section that conforms to the outline of the tool holder and flange. On the said cover plate is also a 40 millimetre filling and draining plug that consist of a threaded hole with an accompanying 50 millimetre diameter screw threaded plug of typically 20 millimetres thickness 41. The plug is machined to 40 millimetres halfway through the thickness, so as to be flush with the interior level of the cover plate. The 5 millimetre ledge that is formed with the plug has a fibre washer or equivalent material 42, of internal diameter 46 millimetres and external diameter 50 millimetres, included to enable a good water-tight seal. On the upper side of the plug and at its centre is a 15 millimetre shaped recess for a 6 millimetre end of a hexagon key, used for tightening said plug into the body of the said cover plate.

The said arrangement is aligned and tightened down evenly and firmly, without over-tightening of the screws, until the whole assembly is secured. The cover plate is designed to have slightly larger dimensions than the said section at its opposite end. The underside of the section has a raised inner layer that conforms closely to the contour of the interior rim of the tool holder 43, while the outer layer is wider than the corresponding rim of the body of the water enclosure so that a good water seal can be achieved 44. Around the rim of the said cover plate, there are 6 millimetre holes drilled into the material and spaced every 60 millimetres apart, and positioned to be accurately in line with the hole of the flange of the tool holder below. Inserted into these holes are winged non-magnetic alloy 5 millimetre screws of 25 millimetres length.

Said screws have a raised collar above the end of the screw thread that acts as a washer against the perspex surface of the said cover plate. The material used is perspex, acrylic or a suitable transparent polymer. Attached to the inner edge of the two layers of the end plate is a soft, deformable and water resistant seal 45, ensuring that when the two sections are brought together, a watertight union is readily formed.

The whole assembly is stood up on its end and water is poured into the assembly until it is full and purged of air. The said plug is screwed in and tightened with the hexagon key until it is firmly within the casing, and the tool holder is water tight (Figures 24-25).

The measurement unit may be accurately levelled prior to testing by use of the adjustor feet.

There are typically four in number and are comprised of perspex I acrylic or other suitable material section attached to each corner on the underside of the tank enclosure.

The assembly is typically a 30 millimetres by 30 millimetres by 5 millimetres thick interface plate. This is permanently fixed to the perspex underside at each of the corners of the tank enclosure. Attached to this and perpendicular at the edges or periphery of the square is a 5 millimetre thick and 20 millimetre high square section that forms an enclosure around the square interface plate. On the surface of this is placed and permanently fixed, another 5 millimetre thick square plate of 30 millimetres by 30 millimetres dimensions. At the geometrical centre of this plate is a 10 millimetre diameter hole. Into this hole is inserted a 12 millimetre diameter by 25 millimetre length perspex / acrylic or othersuitable material sleeve. The said sleeve has been tapped with a coarse screw thread to receive a corresponding 8 millimetre screw shank.

Into the said sleeve is screwed a coarse threaded perspex / acrylic or other suitable material threaded 8 millimetre diameter flat headed pin. The length of said pin is typically 40 millimetres in length and at its lowest end and 5 millimetres from the end is an expanded 5 millimetre thick and 25 millimetre diameter finger adjustor, which has knurling on its outer edge to aid finger adjustments (Figure 26).

The levelling may be performed by individual screwing in / out of the adjustor feet until the bubbles in the spirit levels are at their respective centres. The said tool is now fully set up and ready to be used in conjunction with the user manual. 2b

ADDITIONAL MODULAR EXTENSIONS

The additional modular extensions function to give a readily extendable and multi-configurable platform for evaluation and measurement assessment of other imaging modalities or combined imaging platform(s). The foundation for versatility is the measurement device base plate which is designed to slot into the base frame and to give support to other test apparatus for evaluation of other imaging modalities.

THE ACCESSORY MODULE BASE PLATE

The accessory module base plate 49 is constructed from perspex (RTM), acrylic or other suitably non-magnetic, radiolucent, durable, and transparent polymeric material. It consists essentially of an oblong plate typically 360 millimetres long by 198 millimetres width and 15 millimetres thickness. A partially triangulated groove (base towards the material plate) is cut into the central longitudinal line of the plate from one end to the other and at its deepest point extends 7 millimetres into the material and with a base width of 20 millimetres 51.

This forms a channel by which the complementary shaped interface of the tool supporting block is located, and by which a range of measurement modules may be added in order to test other imaging platforms. On each Outer and uppermost edge of the base plate is a 4 millimetre thick lateral extension of 10 millimetres width that extends 360 millimetres from one end of the Longitudinal line to that of the other 50. On the other lateral edge is another similar lateral extension. Together they function to hold the base plate firmly in place once fitted into the base frame, thereby preventing the base plate from dropping through the frame or adopting an uneven rest position within the frame. The base plate functions to provide a platform by which other accessory modules may be added to the base frame to increase its testing functionality.

At various positions on the lateral surface of the longitudinal edges of the base plate, and spaced millimetres apart, are 30 millimetre deep holes 52 perpendicularly into the material of the base plate. These correspond to the spacing of holes on the lateral aspects of the longitudinal members 2 of the base flame I (Figure 27).

An unthreaded nylon or other suitable non-magnetic material headed locking pin may then be placed into each of the two holes to allow the base plate accessory module to be fixedly or releasably and I or variably secured together with the base frame 1.

THE TOOL SUPPORTING BLOCK ACCESSORY MODULE

The tool supporting block accessory module 53 is typically 360 millimetres length, 20 millimetres width and 164 millimetres height. The base of the block is expanded in a triangular shape so as to closely interface with that of the longitudinal groove of the base plate 54. At its most expanded part, the footprint is only 19 millimetres width and 360 millimetres length.

At the middle point of the supports height there is a similar type of inverted triangular groove on each face of the supporting block. The grooves are typically 20 millimetres width by 360 millimetres length and 5 millimetres deep at their greatest depth 55.

At a point 157 millimetres to the apex of the support section, the width of the block reduces by few millimetres on either edge and then expands to a 19 millimetre base of an inverted triangle that continues along the 360 millimetre edge of the block, and forms an identical triangular based groove with that below 55 (Figure 28).

ACCESSORY MODULE FOR Z-AXIS MEASUREMENT TESTING

OF COMPUTED TOMOGRAPHY (CT) APPARATUS The accessory module for z-axis testing of computed tomography (CT) 56 follows a similar footprint to that of the tool supporting block accessory module with the exception that there is only one triangular expanded foot section on the tool 54. The base of the module is expanded in a complementary triangular fashion so as to closely interface with that of the longitudinal groove of the base plate 51. At its most expanded part, the footprint is only 19 millimetres width and 360 millimetres length. The opposite and uppermost end is a normal square edged face.

The tool module has four horizontal limbs which extend from a point originating from the central line of the vertical section of the tool holder that interfaces longitudinally with the base plate.

Each tool limb is oppositely mounted and separated by specific height intervals and each limb on one particular side is twice the width of its neighbouring limb 57.

The first limb originates from a point 20 millimetres vertical from the floor of the base plate, and is 70 millimetres long and positioned at 90 degrees clockwise to the central vertical line. The second limb originates from a point 40 millimetres vertically from the base along the central line.

and at 270 degrees clockwise for 120 millimetres. The third limb originates from a point 60 millimetres from the base along the central line and at 90 degrees clockwise for 120 millimetres.

The fourth limb originates from a point 80 millimetres vertically from the base along the central line and at 270 degrees clockwise for 70 millimetres (Figure 29).

Each of the limbs has a sectional thickness of 20 millimetres and at each lateral end, symmetrically placed and 20 millimetres from the lateral edge, a 5 millimetre drilled hole that extends longitudinally for the 360 millimetres of the length of the limb.

Into each of these holes is accurately placed a 4.5 millimetre diameter rod of length 360 millimetres length with radio-opaque markers spaced at 10 millimetres intervals for the whole length of the rod 58.

The rod is placed finnly into the full length until the ends are flush with the edges of the drilled hole(s). The same holds for the other four drilled holes incorporated into the tool body. The result of this arrangement is that each shorter opposing limb will be 50 millimetres laterally from the central reference plane of the test and the iso-centre of the field of view (FOV) of the CT scanner and 30 millimetres vertically from the reference rod at the centre of the tool. This reference point can be placed in the iso-centre of the scanner for maximum measurement accuracy. The longer limbs will be 100 millimetres laterally and 30 millimetres vertically from the reference point.

The cylindrical rods are used to generate reference images in each of the orthogonal planes when imaged on the computed tomography (CT) apparatus. The images produced in the axial 59, sagittal 60 and coronal 61 planes respectively, have definite spatial relationships for that plane, and measurement verification in all three planes can be evaluated accurately (Figures 30-32).

The geometrical layout is illustrated in the axial projection (Figure 30) and which shows said cylindrical measurement apparatus in relationship proximity of all other peripheral measurement rods in opposing and staggered limb arrangement to the central reference rod..

The appearances of the scalar markers on computed tomography will in theory generate five sets of parallel lines which when viewed in any plane will give a constant measurement relationship 2 for images generated on the scanner. These will be provided and categonsed for any projection, and the reference relationships should be constant throughout the 360 millimetre length of the imaging tool. In the event of imaging abnormalities, the incorrect measurements will give the locus of positional information anomalies from the iso-centre (middle of the imaging tooJ at +180 millimetres to the iso-centre (zero) to -180 millimetres).

The differences between the measurement values obtained from manufacturer software measurement packages as against the values generated by the testing tool can be then expressed as a percentage variance between the two methods. The tool can be further used to assess the capability of the imaging system of the scanner to resolve measurements that lie in other quadrants of the imaging matrix or further from the iso-centre of the scanner.

The measurements taken by the electronic callipers of the scanner in theory should equal the reference distance(s) along the lengths of the five images of the test tool.

Any significant measurement error(s) of length diameter or spatial relationships between other neighbouring peripheral measurement rods can be quoted in terms of percentage error and may be further correlated by measurement of the three images in axial, sagittal and coronal planes respectively.

THE ACCESSORY MODULE FOR Z-AXIS MEASUREMENT

OF NUCLEAR (ISOTOPE) IMAGING (M) APPARATUS The accessory module for measurement of z-axis isotope imaging 62 may be engaged into the accessory module base plate 49 in the manner previously described for the tool supporting block accessory module 53 and accessory module for z-axis testing of computed tomography (CT), with the exception that the tool supporting block accessory module is replaced with the accessory module for z-axis measurement of nuclear (isotope) imaging 62 (Figure 33).

The module has typical physical dimensions matching that of the accessory module for z-axis testing of CT, namely 360 millimetres length, 20 millimetres thickness, and 157 millimetres height.

The module has positioned at its midpoint horizontally, two locator grooves similar to those for engaging modules on the base plate. The locator grooves serve to hold and position more than one accessory module for more elaborate testing with Single Photon Emission Computerised Tomography (SPECT) and Positron Emission Tomography (PET) scanner units.

At two points 20 millimetres from the apex of the vertical section, and 20 millimetres from the base of the supporting plate, and in line with the central bisector, are round cavities extending from one surface and into the material of the module, and parallel distally to a point of emergence at the other end of the module and parallel to the longitudinal line of the module.

Into this cavity is accurately placed and fed a 14 millimetre square insert by way of example only, or other preferred shape, that is made of a high attenuation material such as lead or steel, or other suitable material, until it emerges at the remote end of the channelled out square cavity of the tool block for the full 360 millimetre length of the tool 63.

The insert itself has a round channel of 10 millimetres diameter by way of example only at its geometric centre, and this also extends throughout the length of the insert. Along the three points of the circular aperture and spaced regularly at typically 40 millimetre intervals, or other preferred length, are pinpoint apertures of typically 0.5 millimetres diameter 65, or other preferred diameter(s), along the length of the measurement tool. Placed securely into this insert is a steel cylinder 64 made typically from steel and of 9 millimetres outside diameter and 7 millimetres inside diameter and 350 millimetres in length, by way of example only. This is designed to carry and seal a plastic tube containing the radioactive substance, typically a metastable salt of Technetium (Tc99m), but other isotopes may be used according to preference.

Along the length of the insert and corresponding to the pinpoint apertures 65 of the imaging tool at 0 degrees, 90 degrees, and 270 degrees are small diameter apertures to allow the radiation to exit (Figures 34-35).

The diameter of the pinpoint apertures is small enough to allow a certain dose rate of gamma radiation photons to pass through so that a suitable pinpointed area may be produced on the scintillation crystal of the gamma camera. The markers on the external faces of the measurement scales 66 typically run from negative multiples of 40 millimetres at one end, for example -160 millimetre, -120 millimetres, -80 millimetres, -40 millimetres, to zero, at the centre of the tool, to a positive multiple of 40 millimetres at the other end, for example 40 millimetres, 80 millimetres, millimetres and 160 millimetres.

At each of the 40 millimetre points is an aperture for the gamma radiation to be emitted simultaneously from the same locus, but from different directions.

The one end has a lead block locator pin 67 that fits into the lead section of the imaging tool to allow the inserts to be located accurately into position(s) to ensure that the pinpoint radiation emitted is of limited and reduced intensity so as to be registered on the scintillation crystal as a small hot spot of recorded high radiation activity (Figure 34).

At each end of the cylindrical insert is a screw thread to allow the fitment of two 6.5 millimetre diameter headed steel screw plugs 68 to cap off each end of the cylinder once the loaded insert is placed within it (Figure 35).

A further disposable 5.0 millimetre transparent plastic insert of 340 millimetres length is used to hold the isotope during testing. The plastic tube is 3 millimetres internal diameter and administration of the isotope is carried out behind lead bricks in a dispensing area. A prescribed activity, for example 30 MBq (MegaBecquerels), is drawn up into a lead shielded syringe. This level of activity is a balance to provide enough radioactive disintegrations to register a "hot spot" of radiation activity on the scintillation crystal so that the acquisition time to register typically Kilocounts is in the time frame of five minutes, rather than in contrast as having a higher level radioactive source (150 MBQ) in the tool that is emanating much higher doses of gamma radiation that may be advantageous for shorter acquisition times, but of limited use because the intensity of the radiation beams from the apertures produce hot spots of large diameter, that they overlap with the hot spot of the neighbouring aperture, at a 40 millimetre distance separation, or create difficulties in defining the centre of the hotspot on the acquired image(s). This would invalidate the accuracy of any measurements derived from use of the accessory module, or at least would limit any inferences or validations of measurement(s) based on the images produced.

Technetium 99m (metastable) is generally the radio-active isotope of choice because of its half-life of three hours.

A hypodermic needle delivers the isotope solution into the bottom of the plastic isotope tube 69 which is in a lead shielded cover and the fluid level is increased with coloured saline to a marked level on the outside of the tube. The coloured saline serves to identify any leaks from the tube assembly and allows identification of fluid level as the plastic tube is filled to level. The coloured saline serves to identify any leaks from the tube assembly and allows identification of fluid level as the plastic tube is filled to level. The coloured fluid level can be easily seen to rise along the inspection window of the lead syringe shield.

Once the correct level has been achieved, the end can be sealed off with a screw and rubber seal 70. The half-life of the isotope of 3 hours allows for a large time frame for testing purposes. The plastic sealing end cap 70 of the plastic isotope tube is engaged with the top screw threaded end of the plastic isotope tube and it is withdrawn from the lead syringe shielding. The plastic isotope tube 69 is then placed into the steel cylindrical tube 64, and the screw caps 68 are screwed to the closed position and then the assembly is fed into the lead housing of the imaging tool 62 until it engages into position with the lead block locating pin 67.

The imaging module is then located into the accessory module base plate 49 and main frame 1, and secured by suitable locking pin and the module is ready for measurement. A second steel cylindrical unit 64 and loaded plaslic isotope tube 69 can be engaged into the lower part of the imaging module in the same manner as described, allowing for more complex 360 degree tomographic plane measurement assessments.

THE SIDE MOUNTED NUCLEAR (ISOTOPE) IMAGING (NI) ACCESSORY TOOL The side mounted nuclear (isotope) imaging module 71 is typically 97 millimetres width, including the 7 millimetre depth of the locating groove, by 360 millimetres length, by 20 millimetres thickness (Figure 36).

The side mounted nuclear (isotope) imaging accessory module may be engaged into the accessory module for z-axis measurement of nuclear (isotope) imaging 62 in the manner previously described. The base of the module is shaped and expanded into a triangular wedge 54 so as to closely interface with that of the longitudinal groove of the accessory module for z-axis testing of nuclear (isotope) imaging 62. At its most expanded part, the footprint is typically only 19 millimetres width and 360 millimetres length.

At its extreme lateral aspect, the lead or steel based insert 63, steel cylindrical tube 64, pin-point apertures 65 and plastic isotope tube 69 are identically positioned within the cavity of the accessory module in order to give an identically arranged and positioned configuration as with the other isotope carrying components within the body of the accessory module for z-axis measurement of nuclear (isotope) imaging 62 and other side mounted nuclear (isotope) imaging accessory tools 71.

The pin-point apertures may be used singly or in a range of combination(s) with other three possible additional nuclear (isotope) imaging accessory units. In these types of configuration, more detailed examinations may be performed on tomographic (the imaging technique of producing sectional images by the rotation of diametrically opposed or relatively offset scintillation detector(s) about a fixed axis that incorporates the volume of highest radioactivity), or Single Photon Emission Computensed Tomography (SPECT) or Positron Emission Tomography (PET) type examinations. The said design of the side mounted nuclear (isotope) imaging tool is illustrated (Figure 36).

The completed accessory module for z-axis measurement of nuclear (isotope) imaging and the engaged side mounted accessory tool is illustrated (Figure 37). Up to three loaded plastic isotope tubes may be placed in any desired configuration. Another variation using four loaded tubes by the addition of another side mounted accessory tool 71 section is illustrated (Figure 38). This arrangement may be used for assessment of tomographic function and distance measurements in the z-axis in addition to 2-Dimensional measurements.

The typical image presentation of this tool is illustrated (Figure 39). This shows the spatial relationships between each of the pin-point apertures as hot spots of signal intensity of a small diameter across the imaging area of the scintillation crystal. The centre of the hot spot to the centre of the next should typically be close to 40 millimetres, with a separation of 100 millimetres between each row of imaged hot spots. The further evaluation of the images and the method of comparative measurement is outlined in the "Methods of Evaluation" section later described.

ACCESSORY MODULE FOR MEASUREMENT OF COMPUTED

RADIOGRAPHY (CR) AND VERIFICATION OF MEASUREMENTS

PERFORMED ON PICTURE ARCHIVE AND COMMUNICATIONS IN

MEDICINE (PACS) CLINICAL REVIEW AND DIAGNOSTIC WORKSTATIONS The accessory module for measurement of computed radiography (CR) 73 may be fitted into the base frame I, with addition of short and long linear measurement tubes 22, 23 for linear measurement testing. This configuration will test validation of images produced by the CR process and will also form the basis for assessment of measurement accuracy of image(s) transferred by networking and teleradiographic image transfer processes.

The module is essentially an imaging section constructed from perspex (RTM), acrylic or other suitably non-magnetic, radiolucent, durable and transparent material. It consists essentially of an oblong block of typical dimensions 360 millimetres length by 198 millimetres width and 20 millimetres thickness. On the underside of the block is an arrangement of radio-opaque markings that when viewed from above describe a number of functional markings, lines and edge indicators. The lines form a square on the bottom aspect of the base of 350 millimetres length by millimetres width. A diagonal line is drawn from each corner to form four triangular sections. Another two lines are drawn from the midpoint of each edge to the centre of the base dividing each of the triangular sections into two.

This in itself forms smaller triangular areas across the base area 74. Along each of these bisecting lines and extending to the edges of the plate are linear scales measured in metric or Imperial sub-divisions of a foot. Typically in the case of a metric scaled base, these subdivisions would be in millimetres and centimetres and extending from the centre point at zero radially to their respective maximum values.

At each of the four corners of base at a point 90 millimetres above and below the longitudinal (or horizontal) centre line and 175 millimetres to the left and right of the transverse (or vertical) centre line are four corner identifiers 75, each set comprising right angled lines of 30 millimetres length (Figure 40). These will delineate the corners for an X-ray field collimation area test (to be described in the "Methods of Evaluation" section.

There is also a circle at the geometrical centre of the accessory module for the vertical central ray of the X-ray tube to be centred prior to radiographic exposure 77. The centring of the radiation source to this will ensure minimal distortion and parallax in the images generated.

In every other triangular section of the module, and inlaid into the polymer substance are functional test units for assessment of image distortion 78, measurement of resolution and Modulation Transfer Function (MTF) 79, sensitometric type testing of the image plate recording system 80, and symmetrical square references for further image distortion evaluation 81. The square references are also image contrast references. Each of the densities of the squares from number 1 to 8 has a respective and reducmg density such that if the contrast level was measured from I to 8, the measurements when obtained and plotted on a graph, would give a straight line response of contrast index versus square reference number.

Testing may be carried out using an added filter equivalent to 1 millimetre of copper to harden the beam and absorb lower energy radiation that may reduce the contrast in the images generated. The test exposure would have to be a standardised dose at a specified distance for the tests to be accurate and image reading should be performed on a preferred computed radiography imaging plate reader, There are also a number of locating holes drilled perpendicularly into the sides of the tool and separated by 40 millimetres. These are recesses for the retaining pins 82 used for securing the accessory module for measurement of computed radiography (CR) into the base frame 1.

The method of testing is detailed in the "Methods of Evaluation" section later described.

THE TUBULAR ACCESSORY MODULE FOR MEASUREMENT

OF COMPUTED RADIOGRAPHY (CR) The tubular accessory module for measurement of computed radiography (CR) 83 consists typically of the oblong frame of the accessory module 84 that may be inserted into the base frame 1, and whose dimensions are typically 408 millimetres long by 198 millimetres width., and millimetres thickness. The frame is divided unequally into three sections.

The first section has its point of origin 123 millimetres from the vertical edge of the left sided column and bounded by a vertical column extending from one longitudinal edge to another. This forms section on the left side of the construction called the main vertical window of the accessory module 85.

Situated at the midpoint of the vertical column is a horizontal column 20 millimetres square, which extends to join with transverse column of the right side of the frame construction. The horizontal column divides the remaining space into two equal portions, a lower section called the lower horizontal window of the accessory module 86, and an upper section called the horizontal window of the accessory module 87. By way of example only, the horizontal column would originate from a point 79 millimetres from the base of the section, the main vertical window would be 160 millimetres transversely and 113 millimetres longitudinally. The two divided smaller sections would be 69 millimetres transversely by 235 millimetres longitudinally. The shape of the resulting construction is illustrated (Figure 41).

At various positions on the lateral surface of the longitudinal edges of the flame, and spaced 40 millimetres apart, are 30 millimetre deep holes 52 perpendicularly into the material of the base plate. These correspond to the spacing of holes on the lateral aspects of the longitudinal members 2 of the base frame 1 (Figure 27).

An unthreaded nylon or other suitable non-magnetic material headed locking pin may then be placed into each of the two holes to allow the base plate accessory module to be fixedly or releasably and / or variably secured together with the base frame I. The frame has a number of retaining clips 88 for holding a specified diameter linear measuring tube in longitudinal, transverse or oblique planes. These are illustrated in perspective and plan views respectively (Figures 42-43). 3RD

The typical diameter for the transverse measurement tube(s) 89 would be 20 millimetres and the tube length 140 millimetres for the left hand vertical tubes. This section would typically incorporate three of the measurement tubes of differing cross-sectional diameter(s) and length(s) of imaging column.

In the upper right hand section of the frame that carries the longitudinal measuring tubes 90, the tube diameter(s) would typically be 25, 20 15 and 10 millimetres cross-section and of tube length 215 millimetres. This section would typically incorporate four measurement tubes of differing cross-sectional diameter(s) and length(s) of imaging column.

The lower right hand section carrying the obliquely mounted measuring tubes 91, would typically require similar diameter measurement tubes of 20, 10 and 5 millimetres cross-sectional diameter and of typical length variations between 235 -160 millimetres length, but with different lengths of imaging column.

In order to allow for the oblique positioning of these tubes, there are wedges shaped into the construction at certain positions in the construction that hold the supporting clips. There are typically three measuring tubes used in this section.

The final construction once assembled can be mounted into the base frame and secured into position with the retaining pins located into the recesses 82 on the tubular tool accessory module.

Each of the measuring tubes will have an imaging volume of fluid contained in the body. The column length of each tube can be varied according to the preferred choices. Typically, in the left hand section a 140, 100 and 60 millimetres length selection are used. In the top right hand section, typically 215, 175, 135 and 100 millimetres length selectionis used. In the lower right hand section, typically 235, 175, and 100 millimetres length selection is used. This is illustrated in plan and side elevational views respectively (Figures 49-50).

COMBINED CONFIGURATION SCANNERS AND TEST TOOLS

The test tool in its most basic embodiment is designed to compare and validate length measurement(s) in images generated by imaging modalities such as Digital Subtraction Angiography (DSA), Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) with or without accompanying water tank enclosure, and Radio-Fluoroscopy (RF).

The tool may be set up and imaged in turn on each of the said imaging modalities, and the measurements derived from the manufacturer based measurement software package can be matched against the length reference(s) contained within the designs of the test tool.

The use of accessory modules is mainly directed to the application of additional modules or devices that confer individual or additional functionality to the tool, above or instead of the level that it provides in its basic form.

The base frame is the foundation of the system, and each modular component will confer a particular aspect of measurement on the configuration of the tool. Each item used in the preferred construction is a functional choice for what is to be measured and for which imaging modality. The constructions are capable of producing information and data that can be compared across different imaging modalities, for example, the measurement peiformance of computed tomography (CT) can be compared against magnetic resonance imaging (MRI), or Digital Subtraction Angiography (DSA) imaging apparatus, for a given test tool configuration. Also, the measurement performance of a particular imaging modality can be compared against other dissimilar scanner models of the same imaging modality or multiple similar scanner models of a particular imaging modality. Further, it would enable the comparative assessment of modality software measurement across different orthogonal planes, and provide information on the measurement conformancy / deviation of more specialised image manipulation and measurement platforms such as multi-planar reconstruction (MPR), curved reconstruction, maximum intensity projections (MIP's), or any other imaging projection, technique or method(s) involving the use of 2-Dimensional or 3-Dimensional graphical representations of anatomy.

COMBINED COMPUTERISED TOMOGRAPHY AND NUCLEAR

(ISOTOPE') IMAGING SCANNERS (TOMOGRAPHY. SPECT OR PET') The combined computed tomography (CT) and nuclear (isotope) imaging tool 92 is a twin modality configuration involving the typical setup for measurement of computed tomography (CT) using reference measurement tubes mounted on the vertical column(s) on the tool base frame I, and also using the accessory module base plate 49, isotope loaded accessory module for z- axis measurement in nuclear (isotope) imaging 62, and isotope loaded side mounted nuclear (isotope) imaging accessory tool module(s) 71. 3$

The base frame is loaded with the base plate and tool supporting block and the required number of side mounted tool sections. The configuration will provide single, multiple plane and tomographic plane linear transverse and longitudinal measurements. The addition of a vertical column at one end (towards the CT scanner end) will allow the attachment of a singularity or plurality of preferred measurement tube(s) for the evaluation of CT measurement performance.

The tool can accommodate easily for the addition of two vertical columns 6 in addition to the accessory module base plate 49, accessory module for z-axis measurement in nuclear (isotope) imaging 62 and side mounted nuclear (isotope) imaging accessory tool module(s) 71, in this type of configuration. Typically, a single vertical column 6 and z-axis measuring tube(s) 12 are matched with a fully loaded tool supporting block for the measurement of combined nuclear imaging and CT imaging apparatus (Figure 46-47). The method of use will be detailed in the "Methods of Evaluation" section later described.

THE MEASUREMENT ACCURACY CORRECTION TOOL

FOR COMPUTED TOMOGRAPHY (CT) The accessory measurement accuracy correction tool for computed tomography (CT) 92 is designed to work in conjunction with the base frame and measurement tube(s) assemblies. The short and long linear 22, 23, and arched or curved z-axis measurement tubes 25 are best configured to be parallel to the imaging plane and can thus be used as a secondary method of length and diameter verification in addition to the intrinsic design of the measurement tube(s).

The measurement accuracy correction tool is also designed to be used in the base of the imaging table of the cross-sectional imaging modality, and can provide a means of comparing measurements made in an oblique plane such as frequently encountered with distorted anatomical structures such as a diseased and aneurysmal aortic vessel.

The application of this module allows for imaging of the patient anatomical region (Figure 48) and the measurement accuracy correction tool to be imaged at the same time, thus being included in the image constructions following the scan(s). Since the module is designed to reside within the table construction, the reference matrix of the tool is unobtrusively included in all but tightly targeted volumes of CT acquisitions, is unobvious when viewing images, and is made perceptible by the reporter lowering the plane of view to the base level in the axial, sagittal, coronal or oblique viewing planes. The corrections can be evaluated by the application of lines 3c of reference, spheres of known diameter and the application of triangles within the measurement correction accessory tool for computed tomography (Figure 49).

The construction of the accessory module is made from perspex, acrylic or other radiolucent and non-magnetic material. The unit consists of a plurality of oblong, square or other suitably shaped section(s) that may be placed either on top of the imaging table, or within the table construction, prior to imaging. The construction of the accessory module comprises a number of not less than two, and typically not more than five planar single sections, in order that the added inertia to the table is mintmised, and that table movement characteristics are not altered. Each complete sectional layer 94 is typically of such a thickness that a 5 millimetre diameter hyper dense sphere of low to moderate x-ray attenuation can be embedded into the middle of the section at a plurality of appropriately positioned loci across the surface of the material to form lines of reference on said section (Figures 50-52).

The separation of these hyper dense spheres is typically 2 millimetres longitudinally and transversely so as to form a square matrix covering the larger aspect of the upper surface of the section 95. The middle layer 96 is different to the other main layers in that it is composed of two longitudinal sections that also have embedded in them 10 millimetre diameter hyper dense spheres of low to moderate x-ray attenuation. There are a number of these type sections in the middle layer and they serve to provide 10 millimetre hyper dense spheres for reference purposes 97. The use of an additional number of similar sized and shaped sections, placed squarely, closely and fixed to the said section(s) will provide a thicker section comprised of a number of thinner sections with additional and similarly placed lines of reference within the section layer 98. They are spaced further apart longitudinally and transversely than in other layers above and below, and are typically spaced by 40 millimetres. The higher diameter spheres function to give reference to the 2, 5, 10, 15, 20 and 25 millimetre size increases for use with computerised diameter platform programs for calculation of diameter(s) that may be dependent upon localised variations in the response of the manufacturer software measurement programs in different locations within the measurement volume. Figure 50 illustrates on a coronal image how lines of reference length can be drawn for measurement comparison purposes. The measurement are that produce a point to point line are always odd numbers and are depicted as 3 centimetre longitudinal axis line 99, a 5 centimetre longitudinal axis line 100, a 7 centimetre transverse axis line 101, and a 5 centimetre oblique axis line 102.

On the first or uppermost of these sections is provided at the one end of the construction, a reference disk and line section 103 that is built into the construction and provides ready access to references, typically a 25 millimetre reference diameter disk 104, a 20 millimetre reference diameter disk 105, a 15 millimetre reference diameter disk 106, a 10 millimetre reference diameter disk 107, and a 2 millimetre reference diameter disk. The reference section also provides lines of reference length, typically a 3 centimetre transverse axis reference line 109, a 5 centimetre transverse axis reference line 110, and a 7 centimetre transverse reference line 111.

The plurality of reference disks and lines are composed of a low to intermediate density material that is embedded into the surface of the uppermost section of the module. The function of these disks of known diameter(s) are to provide a range of reference diameters for the purpose of calibration for additional platform measurement software that may be used to verify and compare the accuracy of values generated by the manufacturer measurement software of the imaging apparatus.

The first of the diameters of the array is typically two millimetres, while the second five millimetres, the third ten millimetres, the fourth fifteen millimetres, the fifth twenty millimetres, and the sixth twenty five millimetres.

The array provides a linear relationship of diameter increase in addition to a base evaluation of the image constructed size prior to any further image manipulation or measurement calculations by the imaging apparatus software.

In order for the relationship between image construction and measurement to be free from spurious or incidental errors, it is important that any measurement accuracy device or measurement software program is able to operate either within the premise of being acquired at the same time as that of the region of the imaged anatomy, or that any measurement accuracy calculations are derived from preferably first order calculations from the raw data or the first generated series image data. This will ensure that other external sources of error are kept at a minimum. The images generated will include the anatomical region of interest that will be seen to be lying on the imaging table. The reporter will orientate the anatomical structure or region of interest into the preferred plane of interest and then a manufacturer software platform will be selected in order to assess the cross-sectional diameter and length of the area of interest. The manufacturer software image measurement and manipulation programs available on the cross-sectional imaging apparatus generally fall into direct measurement of axial, oblique or lateral images, viewing and image manipulation of axial, sagittal, coronal or derived oblique plane of said imaging projection(s). These may be further imaged and manipulated by curved reconstruction, multi-planar reconstruction (MPR) and maximum intensity projection (MIP) imaging platforms. 4'

The values of cross-sectional diameter and length that may reported from these platforms may in themselves be deviant due to a range of underlying reasons, but all may be verified by the inclusion of the measurement accuracy correction tool. This is because the construction of the tool has incorporated into its design an imaging matrix of 10 millimetres square in all directions and for a depth of typically sixty millimetres thickness.

The imaging matrix is placed on the table as part of the imaging table components and other supporting support sections are added above and below the level of the measurement correction accessory tool, so that the patient is made to be comfortable during the CT acquisition process.

Ideally, the measurement correction matrix should be mounted within the imaging table so as to be part of the table configuration (Figure 48). The patient is placed on the scanner 113 in a position on the imaging table to include the region of anatomy under investigation within the available area of the measurement correction matrix 114. The patient is then translated through the scanner 115 until all areas of the anatomy have been scanned and imaged.

When the reporter has viewed and targeted the area of interest on the display screens of the modality workstation, the measurement(s) may be made using the electronic callipers of the reporter measurement tools, and a value for cross-sectional diameter and length may be generated as a linear value. This may in itself may be accurate as has been demonstrated by experimental test methods, but measurement inaccuracy has been shown to occur where distraction from the true orthogonal planes has been observed. The higher the level of deviation, the higher the level of measurement variance, such that the measurement of a structure that appears head on in one plane may appear infinitely long and cannot be measured. Subsequently loading the axial series of images into one or more of the volumetric or 3-Dimensional imaging packages such as MRP, MIP or curved reconstruction will allow another to planes of evaluation whereby another orthogonal plane may be used to present the end on structure a length of anatomy that may be measured accurately from this plane more accurately.

The function of the measurement correction accessory module is to provide a reference matrix based on typically 10 millimetre squares that can be used on all imaging platforms, and that will facilitate comparison measurement evaluation(s) by direct, comparative and interpolational measurement(s), to that given by the manufacturer software reporting platforms. The module achieves this in a number of ways that are not incorporated into these cross-sectional imaging modalities at present.

Firstly, the 10 millimetre squares of the matrix give direct comparison to cross-sectional measurements (2-Dimensional) derived from x-axis to y-axis linear and planar readings, and also for length measurement (2-Dimensional) derived from z-axis linear and planar readings.

Measurement values can easily be matched in any direction and at different magnifications against the reference values of the module placed in the table. The reporter may access the.

measurement correction accessory module matrix by moving the image level reference line into the region of the table in any or the three orthogonal planes. The presence of the higher attenuation spheres of 2 millimetres gives a small centre of reference that will not hinder the placement of electronic callipers and the distance interval to the next neighbouring, and the reference distance between both points is 10 millimetres. In the case of measurement differences between both platforms, a third method of verification may be required as an independent source of reference, although it may be said that the reference tool is composed of a 10 millimetre cube matrix that can be multiplied to larger base multiples. It would not be unreasonable to assume that images produced by the scamier in all three planes should be resolvable by the measurement correction accessory tool.

Secondly, where images have been viewed and measured in oblique planes by the reporter, there have been demonstrated measurement inconsistencies that have been of significantly high levels as to be a cause for concern. Without knowing for certain as to whether the anatomy of a structure has altered significantly as in the case of an aneurysmal aorta in a patient, the only way of verifying the correctness of measurement is by examination using multiple imaging methods (Figure 49). In this case, it is more likely that any high ended measurement variance will be picked up at this stage. In the case of the measurement accuracy correction tool, the strength of its design is that the reference matrix can be applied across all three orthogonal imaging planes, as well as a wide range of oblique plane reconstructions. Where measurements are taken with the electronic callipers across the aneurysm 116, the distance is noted and a second duplicate line is drawn manually or by copy and paste software function 117. The image level cursor line may be dropped to the level of the reference matrix 118 and appropriately windowed in terms of image brightness and contrast, so that the images of the matrix points can be visualised. The duplicated line is also dropped to the proximity of the reference matrix for comparison.

The linear measuring tool can then be again used to measure a line from matrix point to matrix point until a length or length in the region of is obtained 119. Where neighbouring matrix points are not easily visualised due to the image thickness set, this should be increased until other useful points are seen. Where the line is achieved as a result of mapping successive linear points in the reference matrix at oblique angles, it will be noticed that lines corresponding to whole numbers of length are achieved from joining odd numbers of 3 points and above. The design of the reference matrix has been based on a square cubic concept, but also with a 3 centimetre height by 4 centimetre length by 5 centimetre hypotenuse secondary concept that allows a triangle to be drawn in the imaging matrix at the oblique angle of the original manufacturer software measurement taken above. The triangle will enable readings to be taken in three directions relative to the original reading(s). The lengths of each component of the triangle will give a reference length of 3, 4 and 5 centimetres length that is variant may be seen as degree(s) of measurement inaccuracy prevalent in that plane of viewing.

Other combinations using the concepts of using equal length between two 1 centimetre intervals of the matrix my yield triangles with similar vertical, longitudinal and transverse length of 2 centimetres by 2 centimetres with a hypotenuse length of the square root of 8 which is equivalent to 2.828 centimetres (to three decimal places), and on a smaller scale 1 centimetre section by I centimetre similar length side triangle with a hypotenuse length of 1.4 14 centimetres. The combinations of said method of applying Pythagorean concepts to the triangles in order to calculate or infer length measurement calculations within or relative to the matrix is by way of example only and may be extended to other combinations of longitudinal, transverse and oblique plane measurements.

Correspondingly, the length of the duplicated original measurement may be compared with that of the component line of the triangle that best approaches that of the oblique plane of the original reading. These types of comparison readings can be taken in any orthogonal or oblique plane and across the width of the imaging table and provides a reasonably fast and accurate method of verifying linear diameter and length of manufacturer software generated value against the reference matrix.

in figure 49, a line drawn parallel to the reading line passing through the area of interest may be of correct length, but may show inaccuracy by magnification due to the distance traversed to the detector and the fan beam characteristics of the X-ray source. Also, a degree of geometrical distortion may occur due to the increased distance traversed by the X-ray beam in reaching more laterally situated detectors in the detector array of the scanner. 4Sç

Consequently, the registration of the image and measurement of it may give an inaccurate result Use of the concept of triangles will enable the hypotenuse length to be easily calculated and a more representative length measurement of the anatomical structure to be achieved 118.

Other lines drawn from the anatomical structure vertically down to the reference matrix will likely be inaccurate since they do not truly represent the structure being imaged and represent a variable and detrimental degree of geometrical distortion 120.

Thirdly, the use of a platform based diameter and length reference software platforms may be used to indicate the variance in measurement accuracy under a range of conditions. The reference section of the upper matrix layer has typically 2, 5, 10, 15, 20 and 25 millimetre diameter low to medium attenuation value disks that serve as reference and calibration objects for these types of tests. Also incorporated are reference lengths of typically 30, 50, and 70 millimetres for linear measurement calibrations.

The use of these as references will allow an initial evaluation of the system and overview of the scanner system software to reproduce known referenced objects in terms of diameter and length.

Consequent use of other platform software programs could be devised so that the x-axis and y axis components of the diameter measurement software could be made to be independent moveable so the two or more different diameters involved in the measuring of circuLar, elliptical or otherwise shaped objects could be more realistically evaluated in terms of measurements of external diameter(s), internal diameter(s), area or volume of segment. The length measurement software should be configured so that it is able to provide linear length, tied and cumulative linear sections (for non-linear or line variant structures).

Fourthly, the in-built references of the measurement correction accessory module 93 may be used as a universal reference for images generated in all planes. Failure of measurement accuracy may be attributed to the inability of the processing algorithm of the software measurement protocol to resolve length or diameter changes that are either close to or at 0 degrees or 180 degrees to its reading axis.

The consequence of this is that the algorithm does not register changes that are at or close to zero in the reading plane. Viewed at 90 degrees relative to the reading plane, these smaller registered changes may be representative of larger changes as viewed from a perpendicular point or different orthogonal plane, but will never be reflected in the final generated image or associated measurement value taken in the reading plane.

The accessory module as part of its construction has 2 millimetre and 10 millimetre diameter hyper dense spheres that may be used for comparison or calibration purposes, and a further planar reference section with 2, 5, 10, 15, 20, and 25 millimetre disks of a few millimetres thickness.

The construction of an overlay measurement platform that is able to interface with the imaging matrix of the of the imaging apparatus and display would enable independent values of diameter and length to be generated using known references, applied in that plane, and viewed as the imaged object(s), and with it compared to actual values based on the raw image data that was acquired during the scanning procedure. The use of an interface introduced within a layer to the graphical user interface could be linked to the scanner data files, so that a program generated volumetric reference matrix could be constructed and used to overlay onto the displayed image by its property of dynamic data link, and could easily be updated by event of change of image or view to give an updated set of tabled values including size of focus, collimation, number of slices per part of rotation, field of view, table index and number of sections acquired. The volumetric reference matrix could be calibrated against the planar and spherical reference objects of the measurement correction accessory module 93, and could then be positioned onto the structure to include the desired range of coverage and the preferred orientation in x, y and z planes so that the measurement evaluation once performed would generate an additional set of data to that provided by the manufacturer software. The differences with the data derived by this type of computer generated 3-Dimensional matrix box is that most of the calibrations regarding diameter and length can all be obtained from measurement(s) taken of the measurement correction accessory module 93 which was obtained at the same time during CT scanning as the structure being examined. As a result of this, the data should be dynamically linked to the image and measurement parameters of the imaging modality, such that the volumetric box could be rotated in any plane and position, and could be regarded essentially as independent to the scanner software measurement interface. The registration of values relating to a particular image may then be indicated from the table position and the software interface controlling its movement, and the software generated volumetric box that may be moved into position and locked to particular key sectional images within a defined range of images or table movement. This will then register the range of variance of diameter(s) and length(s) as defined by the activity of the electronic callipers of the manufacturer measurement software and the differences in values obtained in another sections of the results table derived by the measurement comparison software.

THE MEASUREMENT ACCURACY CORRECTION TOOL

FOR MAGNETIC RESONANCE IMAGING (MRI) The measurement accuracy correction tool for magnetic resonance imaging (MRI) is similar in design and construction to the measurement accuracy correction tool for computed tomography (CT). It has a typical construction comprising of 5 interfaced oblong and planar sections 12 1-125. The material used is typically perspex, acrylic or other preferred transparent and non-magnetic material with a layer thickness of typically 10 millimetres. In the correction tool, each of these sections will interface together to form the basic functional unit that will allow single or multiple level(s) of evaluation / comparison of length to be made from the radiological or magnetic resonance image(s) produced.

The unit(s) may be table mounted and would be typically placed between the patient anatomical area being scanned and the detector coil array(s) in order that its image may be compositely recorded under the same conditions of scanning, and at the same time as that of the patient.

The images should be obtained at the same degree of magnification and location as the preferred anatomical area being imaged, and the single layer reference matrix of the correction tool may be accessed, as in the case of viewing computerised tomography (CT) images by lowering the plane of visualisation to the level below the patient. It is important however that in order to incorporate the reference matrix of the correction tool into the image, the field of view has to be set to a large enough value at the localisation part of scanning, and it is advisable to use three orthogonal planes in order to indicate the degree of reference matrix inclusion.

If technology allows in the future for larger diameter interiors of magnetic resonance scanners, then measurement accuracy correction tools could be constructed with more reference layers in the matrix, allowing for a greater range of freedom in resolving measurements involving greater degrees of obliquity. The tvlRl measurement accuracy correction tool 126 in its current embodiment is capable of verifying longitudinal and transverse linear measurement(s), diameter(s), area(s), and volume(s) by comparison to references in-built in the construction of the tool.

Arranged in lines longitudinally and transversely on both the upper and lower surfaces of each perspex section is a plurality of indentations that are situated equidistant to the next indentation with a separation of typically 20 millimetres, although this spacing is by way of example only, and the repeated fashion of this configuration creates an area of 20 millimetres recurrent pattern to the extreme margins longitudinally and by depth of said perspex layer in the sagittal plane (Figure 55), and by 20 millimetres separation longitudinally and transversely in the coronalplane (Figure 56). The axial or transverse view displays the matrix as being based on 20 millimetre wide squares of 30 millimetres depth (Figure 57).

Each indentation forms a hemisphere of 2.5 millimetres radius, by way of example only, on the one side that is engineered to be interfaced with the corresponding upper or lower surface of the next layer, and by which the combination of the two indentations in the shape of hemispheres forms a complete sphere of 5 millimetres diameter. The hemispherical indentations on the second layer are hUed with 5 millimetre diameter oil or other equivalent material capsules. The interfacing of the lower surface of layer I with the upper surface of layer 2 will create complete spheres filled with the oil or equivalent material capsules 126.

The third layer of the construction fits beneath the second but does not carry any oil or its equivalent capsules. The fourth layer interfaces below the third layer and carries another plurality of oil capsules that are encased by the upper surface of the fifth layer. The resulting construction is illustrated (Figures 55-57). These substances should contain high numbers of loosely bonded hydrogen nuclei as part of their molecular structure. This will provide a good MRJ signal on magnetisation by the exciting radio-frequency pulse of the MRI sequence, and by the subsequent relaxation process, the emanation of a strong or high signal-to-noise ratio (SNR) pulse that will appear as a bright 5 millimetre diameter spots in the sections between layers I and 2 and 4 and 5. The images from these locations define the points of reference for the measurement correction tool matrix for MR imaging. The plurality of capsules between the layer(s) will show when viewed, a number of linearly arranged and spaced squares that are highlighted by a plurality of 5 millimetre diameter bright spheres forming a 40 millimetre square matrix with 50 per cent overlapping of another 40 millimetre square at a point 20 millimetres from the origin of the first.

The concept of using a 3 centimetre x 4 centimetre x 5 centimetre triangle or variants may be applied, as in the case with the computed tomography (CT) measurement correction tool, with the exception that it can only be applied at one level due to the limitations in the available thickness of the correction matrix to fit into the tables of some types of MRL scanners. This would enable direct, comparative and interpolative measurements to be made against the values provided by the manufacturer based measurement software package.

The correction tool even in this more limited state is able to verify accuracy of linear measurement in longitudinal, transverse and depth planes 128.

By introduction of the triangle geometrical comparisons it is possible to check oblique plane measurements in the top right to bottom left planes 129 and the top left to bottom right planes 130. Further comparison to the sphere diameters may allow size comparisons with regard to diameter(s) of objects, and when linked to computer based platform software measurement programs may also allow areas and volume calculations to be performed and compared against the values given by the imaging modality manufacturer based software measurement program.

In conclusion, the magnetic resonance imaging correction tool is able to verify and compare the integrity of measurement values derived from other computer generated measurement process by matching their values as against the longitudinal, transverse and depth reference spheres integral to the tool. Measurement anomalies may arise due to asymmetry of the imaging matrix of the scanner or a loss or failure of calibration of spatial references within the imaging volume.

OVERVIEW OF THE RANGE OF APPLICATIONS FOR THE APPARATUS

FOR MEASUREMENT ACCURACY TESTING OF RADIOLOGICAL IMAGENG

MODALITIES AND NETWORKED DIGITAL IMAGING PLATFORMS

The apparatus for measurement accuracy testing of radiological imaging modalities and networked digital platforms is an inherently versatile and universal tool in its capability to be used as a distance and cross-sectional diameter reference image model for a wide range of radiological imaging modalities. In its most basic form, it may be used to produce, by virtue of the imaging process, single or multiple reference images for comparison of measurement values derived from the manufacturer software measurement platforms that are provided with each imaging modality. The range of modalities capable of deriving the benefit of verified image measurement are Digital Subtraction Angiography (DSA), Computed Tomography (CT), Magnetic Resonance Imaging (MRI) with or without using water tank enclosure, Nuclear (Isotope) Imaging (NI) and Radio-Fluoroscopy (RF). The use of additional accessory modules is mainly related to the additional devices which give enhanced functionality to the tool, above the basic level provided, so it is able to be applied across more imaging platforms.

The base frame is the foundation of the system, and each modular component will confer a particular aspect of measurement capability on the performance of the tool. Each item used in the preferred construction is a functional choice for what is to be measured and for what modality is 4c4 to be investigated. The constructions are capable of producing information and data that can be compared across different imaging modalities, for example, the measurement performance of computed tomography (CT) can be compared against magnetic resonance (MRI), or digital subtraction angiography / imaging apparatus (DSA), for a given tool configuration.

Also, the measurement performance of particular imaging modalities can be compared against.

each other in the case of multiple similar or dissimilar type installations of for example magnetic resonance scanners in a given department.

Further, it would enable the comparative assessment of software measurement across different orthogonal planes, and provide information on the measurement conformancy / deviation of more specialised platforms such as multi-planar imaging (MPR), curved reconstruction, and maximum intensity projections (MIP), or other imaging projection techniques using 2-Dimensional or 3-Dimensional graphical representations of tissue anatomy.

TECHNICAL OVERVIEW OF MAGNETIC RESONANCE IMAGING (MR1) AND COMPUTED TOMOGRAPHY (CT) Both MRI and CT use different physical principles to generate their image data. MRI uses the application of strong magnets to magnetise the body tissue that lies in its scanner bore. An applied radio-frequency (RF) pulse is then applied at a certain resonant frequency by transmit coils within the scanner to cause the hydrogen nuclei in the body tissue to flip over in a precessional maimer and to increase its internal energy. Removal of the RF pulse allows the energy in the tissue to naturally dissipate by internal interactions with other hydrogen nuclei in the vicinity, and also by electronic interactions with unpaired electrons in the substance of the tissue. The energy dissipated follows time curves, and is given out as RF pulses that are picked up by the receiver coils of the scanner. This then forms the digital signal that forms the medical image. Each event is picked up by the coils arrays and the position is resolved into three components, an x-axis, y-axis and z-axis. This then becomes the basis for volumetric or 3-Dimensional scanning.

MRI scanners have been developed to produce images derived from interrogation and processing of sectional or volumetric datasets. It is from these datasets that images can be measured in a 2-Dimensional mode using conventional x-axis and y-axis point-to-point measurements or by interpolation of multiples of sectional slices to generate z-axis or third dimension length measurements using manufacturer software applications such as curved reconstruction, Maximum Intensity Projection (MIP), or Multi-Planar Reconstruction (MPR).

Measurement in a 3-Dimensional image requires volumetric data or interpolated 2-Dimensional sectional data from a series of images, in order to provide measurement in the z-a.xis. These types of measurements pertain typically to length of a structure or extent of a lesion.

CT is an imaging modality that irradiates the body tissue with a narrow beam (fan or other configuration) of X-radiation. Differential absorption of the beam by various structures in the tissue will form an attenuation pattern that will be registered by the diametrically opposed detector array of the scanner.

As the tube and detector array revolve around the patient a 2-Dimensional image is formed that appears as if the patient had been cut into half and the anatomy viewed end on. Gradual advancement in stages of the body part to be imaged will give a series of cross-sectional images of the anatomy of the body part.

On newer volumetric or 3-Dimensional scanners, the patient is continuously moved or translated through the revolving X-ray tube I detector array arrangement, and a continuous data stream of information is recorded by the detectors. This will comprise of the attenuation values of all the structures of the body part traversed during the acquisition. Each value of attenuation can be resolved into a value (Hounsfield) and 3 spatial components in the x, y and z axes. The data is volumetric and images can be constructed automatically into 2-Dimensional images stretching from one end of the imaged body part to the other. This is also important because z-axis measurements typically relate to length of a structure or the extent of a lesion.

Reconstructions can be made to create further image series in any desired plane of interest.

Images are presented on typically 512 X 512 or 1024 X 1024 matrices, and point-to-point measurements can be made in any direction with accuracy defined by reference values of points of interest that occupy a specific locus in the imaging matrix. 5'

DESCR[PTIONS OF THE FUNCTIONING OF EACH OF THE TOOLS TEST TOOLS FOR TESTING ACCURACY OF DIGITAL SUBTRACTION A}4GIOGRAPHY (DSA)RADIO-FLUOROSCOPY (RF). COMPUTED TOMOGRAPHY (CT) AND MAGNETIC RESONANCE IMAGING ( MRI) MODALITIES The successful design and subsequent fabrication of a predecessor testing tool of the herein described volumetric measurement testing apparatus, has created a substantial volume of operational knowledge and experimental data on 2-Dimensional and 3-Dimensional image acquisitions using modem volumetric CT and MIRI scanners. It has also allowed comparison of measurement accuracy with other dissimilar image modalities such as with DSA and RF imaging apparatus. Due to the large amount of data collected, large number of recorded images, the number of data tables produced and additional derived information tables, a methodical and disciplined approach to scientific evaluation and presentation of its factually based and inferential data has led to the conclusion that the test tool has proven itself to have integrity, reproducibility and reliability in its modality testing abilities that can be applied across a range of dissimilar imaging platfonns. The success of this basic tool has led to the design now presented for patenting protection.

The test tool is essentially a family of tools and measurement accuracy correction tools for cross-sectional imaging which can be used on single or multiple radiological imaging platforms. The volumetric test tool is almost universal in its ability to assess and evaluate the measurement compliancy / deviance between different imaging modalities, for example, DSA, RF, CT and MRJ. Additionally, the images produced by each respective modality can be used to validate the performance of manufacturer installed measurement software that involves the loading of the volume of scan image data, acquired during the scanning process, into 3-Dimensional viewing, image manipulation and measurement platforms, typically Multi-Planar Reconstruction (MPR), Maximum Intensity Projection (MIP), and curved reconstruction.

The base frame 1, vertical column assembly 6 and measurement tube(s) II, create a tool that may be set up and tested on each modality in turn, without the need to be changed in any way, in order to conform to safety regulations for each type of equipment. The base frame allows for a common platform with extensive capabilities of variability for position, orientation, and mounting of a number of measurement tubes. The high degree of variable configuration of this tool apparatus allows it to test each of the modalities under considerable range of conditions of tortuosity, such that the images produced, their clarity, and their representations of diameter and length, are held to the highest levels of scrutiny, that evidently does not exist in medical physics testing routines. Since the construction of the measurement tubes enables z-axis evaluation, or measurement in the third dimension, images may be obtained from each modality, or any particular type of machine of a given modality, and these may be correlated for measurement accuracy across all the mentioned types of equipment.

The measurement tube design is at the heart of the referencing system. There are three aspects of the referencing tube(s) design that allow them to function as an independent reference. Firstly, there is no change in tool configuration during the testing of any range of imaging machines mentioned above, so the internal validity of the testing methods are likely to be unaffected by spurious errors in the setting up of the tool, and by the dissimilar natures of the imaging modalities stated. Secondly, the tool is able to effectively function as a reference for length primarily due to the high attenuation central wire, along with its 1 centimetre notches, and also secondarily due to the attenuation values of the measurement tube and encapsulated imaging volume, which in itself is used to accurately indicate both length(s) and diameter(s).

Thirdly, the fluid characteristics of the oil in the measurement tube(s) function to give attenuation to the X-ray beam and so delineate boundaries within the measurement tube, that accurately indicate the said measurement parameters of length, diameter, and volume. Also, the fluid under the influence of radio-frequency (RF) excitation, as in the case of MRI, is able to release the excess energy following cessation of the applied magnetic field, to give a RF pulse of high enough energy and of a suitable wave characteristic to be read by the instrumentation of the MRI scanner.

The inventor has been successful in demonstrating consistent and reliable measuremenis that confirm the integrity of DSA, CT and MRJ imaging modalities. It has further shown the predictive points where measurement deviance and inaccuracy begin to occur.

The test protocols that were employed have been conducted according to a scientific testing methodology that accounts for measurement(s) derived by the aforementioned imaging modalities, to evaluate cross-sectional diameter(s) of single, multiple or series scanned images of the reference measurement test tool, or any planar variant of said parameter, and the linear, curvate, curvilinear, or other variant of z-axis point-to-point(s) progressive measurement(s) that #3 The test tool when configured in one way has been able to demonstrate both high and acceptably compliancy of measurement accuracy in these types of measurement(s), and when configured in another more tortuous form, it further demonstrates an unacceptably wide degree of variability in the degree of accuracy in the reporting of the tested reference tool cross-sectional diameter(s) and length(s). The shape(s), diameter(s), length(s), and number of testing volume(s) of said testing tool apparatus are designed and configured to provide a range of reference based tube diameter(s), tube length(s), a plurality of regular, accentuated and extreme level(s) of tortuosity or tube curvature(s) in configurations designed to progress and traverse across multiple points of the x, y and z axes (across orthogonal planes) in a single, series or combination(s) of directions.

The resultant progressive and deviant nature of the test tool imaging volume(s) or compartment(s) will cut across a minimum of two out of the three orthogonal (at right angles to each other) planes (or sub-divisions of I or contributing towards 90 degrees clockwise / anti-clockwise variance relative to the x, y and z axes of the scanner imaging matrix (matrices) in less tortuous tools, or to up to three orthogonal planes (or sub-divisions of / or contributing towards degrees clockwise / anti-clockwise variance relative to the x, y and z axes of the scanner imaging matrix (matrices) in moderately tortuous tools, or to enable combinations or multiples of variation(s) in orthogonal planes (or sub-divisions of! or contributing towards 90 degrees clockwise I anti-clockwise variance relative to the x, y and z axes of the scanner imaging matrix (matrices) in highly convoluted complex tortuous configuration(s).

Radiographic diagnostic imaging platforms are an essential component of any universal healthcare delivery system such as found in any large hospital. The imaging modalities commonly found are Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Digital Subtraction Angiography (DSA), Radio-fluoroscopy (RF), Ultrasound, Nuclear (Isotope) Imaging (NI), and Computed Radiography (CR).

Much of the increased sophistication of these imaging modalities can be attributed to developments and innovations in imaging technology, evolution of computer hardware and software, and improvement in the conformancy standards of image transmission through hospital networks.

On all of the modalities used in radiology, there is usually a Microsoft Windows (RTM) or other system such as UNIX (RTM) that interfaces the diagnostic modality to the hospital information systems. Expansion of the services required to share information between hospitals is the next major hurdle faced by imaging, technical, and developing technologists.

The technical specifications and performance of medical devices and apparatus are set by government bodies and all fall under the jurisdiction of the Department of Health.

The Medical Devices Agency (MDA) investigates, evaluates and report the performances of manufacturer equipment with regard to operation within legal or specified limits.

On a local basis, the maintenance, performance, replacement of faulty parts and hardware / software updates are carried out under contract by manufacturer trained engineers. The software performance however, is checked and monitored by medical physicists, and compared to locally agreed levels and limits. The tests essentially carried out by medical physicists typically involve the 2-Dimensional imaging and measuring of modules or planar test phantoms. A detailed description of the testing methods and tool used currently by medical physicists is given in appendix 1.

The invention has been devised to address the absence of z-axis measurement evaluation that exists generally for all CT and MRI scanners. It also addresses the incomplete assessment of measurement of linear, non-linear, curved or otherwise, across a volume of acquired image data.

As of this date, the inventor has not been able to find any relative articles or information relating to this specific subject.

The tool has been based on a modular approach so that it may be applied across multiple imaging modalities, so that for the first time, different imaging modalities may be compared for measurement accuracy against each other. Up until now, all testing of imaging equipment has required a different range of test tools. This tool may be effectively used to assess measurement compliance and deviation in each modality using 2-Dimensional and 3-Dimensional dataset images from the same image acquisition. There is no available tool on the market that offers this possibility and as a consequence, the testing of this aspect is not current practice. There are no medical journal articles to verify that this is the case outside of this country.

The tool can also be configured to show the failure of manufacturer software measurement reporting platforms to give accurate and consistent measurements of reference images as against known reference values.

RESULTS OF MEASUREMENT TESTING OF PROTOTYPE TEST TOOL USING DIGITAL

SUBTRACTION ANGIOGRAPHY (DSA). COMPUTED TOMOGRAPHY (CT).

AND MAGNETIC RESONANCE IMAGING (MRI) IMAGING MODALITIES The vascular test model that preceded the design of the model specified in the patent application was of a more basic design, but it nonetheless demonstrated the intrinsic features required in such a tool, in order for it to function as the said measurement reference tool. The original tool was comprehensively tested using a scientific methodology, and the tool was imaged in turn by digital subtraction angiography (DSA), computed tomography (CT) and magnetic resonance imaging (MRI). There were no changes to the tool configuration for any safety requirements for any of the imaging modalities, so random errors were maintained at a minimum level.

Literature searches of radiological, medical and technical journals were conducted to see whether there was any specialised knowledge or previous experimental work carried out by other scientists or investigators. The results were negative so internet searches were made with a number of established search engines, and this also revealed that had been no research conducted in this area of investigation to date, and no experimental work documented on studies with similar technical objectives or methods of testing as in this study.

The tool has in its own right produced somewhat controversial results regarding the integrity of what radiological reporters may be providing to hospital clinicians in good faith and in the light of current knowledge and best practice. The results included in the tables have been chosen from a volume of test data derived from the experimental testing regimes. It will be noticed that the test tool was able to favourably compare its measurement results with that of the results of the manufacturer modality software measurement package, and equally was able to be configured to show marked measurement differences in comparison to the modality measurement software.

This shows the strength of the test tool design by virtue that it is able to test the modality hardware / software designs at variable levels of conformancy.

The tool also demonstrates the variance in results obtained by different methods of distance calculation using modality 3-Dimensional software such as curved reconstruction, multi-planar reconstruction (MPR) and maximum intensity projections (M[P's).

In tables 1 and 2 the five test tool configurations are imaged and measured by the researcher and "blind" reported by a interventionalist consultant radiologist.

The broader section of the model has been modelled to represent the typical calibre of a healthy aortic vessel (main artery in the abdomen) with cross-sectional diameter of 18 millimefres, and the thinner section modelled to represent the typical calibre of an iliac artery (artery supplying the leg) having a cross-sectional diameter of 9 millimetres. The results have been colour coded for easy recognition of deviance of measurement values. For ease of reading the relevant table.

information, a colour scheme has been adopted to readily show any differences from the values set. Selected data sheets have been included for reference only to give a condensed and readily appreciable account of the results of the original study.

This is as follows; Green -Over-read up to 5% , Yellow -Under-read up to 5% E1 Blue -Unity (Same measurement value as that set) values that lie between + or -5.01 to 10.00% or values that exceed + or -10.01 or over AORTIC TEST TOOLS 1-5

AORTIC BODY AND ILIAC VESSEL MEASUREMENTS

DIGITAL SUBTRACTION ANGIOGRAPHY

TEST TOOL 1 Aortic body marker distance = 2 13.0mm. Iliac vessel marker distance = 99.0mm.

Tool configuration: Shallow tortuosity of aortic body and iliac vessel.

The researcher and interventionalist tended to over and under-estimate the cross-sectional diameter of the aortic body by between 14.48% to 3.03% and 3.03% to -2.69% above and below the test tool reference value respectively. The highest value recorded from the researcher dataset was achieved with the lateral DSA view which generally tends to be the most magnified of the four views recorded. The interventionalist value was marginally more accurate than that of the researcher (Tables 1-5).

Linear marker distance measurement of the aortic body section for both researcher and interventionalist was marginally under-estimated by between -0.6 1% to -1.27%, and 0.00% to -1.30% respectively (Tables 1-5). 5?

One of the interventionalist values was at unity with the reference leveL The interventionalist values were marginally more accurate than those of the researcher, but both were very close generally to the test tool reference values (Tables 1-5).

The iliac vessel cross-sectional diameter measurements varied between 5.45% to 4.89% for the researcher, and between 50.64% to 15.87% for the interventionalist (Tables 1-5).

The iliac vessel marker distance measurement varied between 9.60% to -7.07% for the researcher, and by between 11.11% to 7.07% for the interventionalist measurements above and below the test tool reference values respectively (Tables 1-5).

TEST TOOL 2 Aortic body marker distance = 163.0mm. Iliac vessel marker distance 91.0mm.

Tool configuration: Increased tortuosity of aortic body and iliac vessel.

The researcher and interventionalist tended to over-estimate cross-sectional diameter of the aortic body section by between 9.20% to 3.45%, and 9.20% to 3.45% above and below the test tool reference values respectively (Tables 1-5). The highest value recorded from the researcher dataset was achieved with the lateral DSA view, and the most magnified of the four DSA views.

The researcher value was marginally more accurate than that of the interventionalist.

Linear marker distance measurement of the aortic body by both researcher and interventionalist tended to be generally under-estimated by between 0.55% and -0.74%, and 0.00% to -0.61% above and below the test tool reference values respectively.

One of the interventionalist values was at unity with the test tool reference level. The interventionalist values were marginally more accurate than those of the researcher, but both were very close generally to the reference value (Tables 1-5).

The iliac vessel cross-sectional diameter measurements were -1.85% below the test tool reference value for all four views measured by the researcher, and between 52.67% to 9.05% above the test tool reference value for the interventionalist (Tables 1-5).

The iliac vessel marker distance measurement varied by between 9.89% to 6.04% above the test tool reference value for the researcher, and between 2.20% to -1.10% above and below the test tool reference value for the interventionalist measurements. The interventionalist value was more accurate than that of the researcher (Tables 1-5).

TEST TOOL 3 Aortic body marker distance = 103.0mm. Iliac vessel marker distance = 62.0mm.

Tool configuration: More increase in tortuosity of aortic body and iliac vessel.

The researcher and interventionalist tended to marginally over and under-estimate the cross-sectional diameter of the aortic body by between 15.34% to 3.81% and 9.57% to -1.96% above and below the test tool reference values respectively (Tables 1-5). The highest value recorded from the researcher dataset was achieved with the lateral DSA view. The researcher value was marginally more accurate than that of the interventionalist.

Linear marker distance measurement of the aortic body for both researcher and interventionalist tended to be generally under-estimated by between 0.87% to -9.6 1% and -0.49% to -1.94% above and below the test tool reference values respectively (Tables 1-5). Both of the datasets werevery close to the reference value, with the exception of -9.61, due to the lateral projection used. The researcher values were marginally more accurate than those of the interventionalist.

The iliac vessel cross-sectional diameter measurements were 10.97% above the reference value of the tool section for all four views measured by the researcher, and between 47.97% to 10.97% above the test tool reference value for the interventionalist measurements (Tables 1-5).

This was due to a default diameter of 9.0 mm being used due to the difficulties in using electronic callipers on axial images, and the tendency for the calliper to drop across and into the next adjacent pixel. Accurate measurements at this magnification were not possible using with this method and small but predictable inaccuracies were evident.

The iliac vessel marker distance measurement varied by between 4.68% to 0.32% above the test tool reference value for the researcher, and by between 8.06% to 1.61% above the test tool reference value for the interventionalist measurements (Tables 1-5). The researcher values were considered to be marginally more accurate than that of the interventionalist.

TEST TOOL 4 Aortic body marker distance = 85.0mm. Iliac vessel marker distance = 50.0mm.

Tool configuration: Highly tortuous aortic body and iliac vessel.

The researcher and interventionalist tended to marginally over and under-estimate the cross-sectional diameter of the aortic body by between 21.11% to -1.96% and 3.81% to -1.96% respectively, above and below the test tool reference value (Table 1-5).

The highest value recorded from the researcher dataset was achieved with the lateral DSA view.

The interventionalist value was marginally more accurate than that of the researcher, using the three best projections out of the available four.

Linear marker distance measurement of the aortic body for both researcher and interventionalist tended to be generally well estimated by between 3.4 1% to -0.94% for the researcher measurements and by between 0.00% to -2.4 1% at or below the test tool reference value for the interventionalist measurements (Tables 1-5). The interventionalist values were marginally more accurate than those of the researcher and one of the values was at unity (0.00%) with the reference value.

The iliac vessel cross-sectional diameter measurements varied by -1.85% below the test tool reference value for the researcher measurements for all four views recorded, and by between 19.96% to -1.85% above and below the test tool reference value for the interventionalist

(Tables 1-5).

The iliac vessel marker distance measurement varied by between 8.80% to 8.OO% above and below the test tool reference value for the researcher, and by between 10.00% to 0.00% above or at the test tool reference value for the interventionalist (Table 1-5).

The interventionalist values were considered to be marginally more accurate than that of the researcher, and one of the measurements was at unity (0.00%) with the reference value.

TEST TOOL 5 Aortic body marker distance = 202.0mm. Iliac vessel marker distance 93.0mm.

Tool configuration: Highly degree of antagonistic tortuosity of aortic body and iliac vessel.

The researcher and interventionalist tended to over-estimate the cross-sectional diameter of the aortic body by between 9.57% to 3.8 1% above the test tool reference value for the researcher measurements, and by between 7.27% to 0.35% above and below the test tool reference value for the interventionalist measurements (Tables 1-5). The highest value recorded from the researcher dataset was achieved with the lateral DSA view. The interventionalist value was marginally more accurate than that of the researcher using the three best projections of the available four.

Linear marker distance measurement of the aortic body for both researcher and interventionalist tended to be generally under-estimated and between 1.93% to -4.50% above and below the test tool reference value for the researcher measurements, and by between -2.48% to -4.70% below the test tool reference value for the interventionalist measurements (Tables 1-5). The researcher values were marginally more accurate than those of the interventionalist.

The iliac vessel cross-sectional diameter measurements varied by -1.85% below the test tool reference value for the researcher measurements, and by between 2.5 1% to -0.76% above and below the test tool reference value for the interventionalist measurement (Tables 1-5).

The iliac vessel marker distance measurement varied by between -1.08% to -10.32% below the test tool reference value for the researcher measurements, and between -13.98% to -15.05% below the test tool reference value for the interventionalist measurements (Tables 1-5).

The researcher values were considered to be marginally more accurate than that of the interventionalist.

COMPUTED TOMOGRAPHY

TEST TOOL I

Aortic body marker distance = 213.0mm. Iliac vessel marker distance = 99.0mm.

Tool configuration: Shallow tortuosity of aortic body and iliac vessel.

The researcher tended to over-estimate the cross-sectional diameter of the aortic body by 0.57% above the test tool reference value while the interventionalist under-estimated by -1.7 1% below the test tool reference value using conventional 2-Dimensional point to point measurement. The researcher value is marginally more accurate than that of the interventionalist (Table 6).

Linear marker distance measurements of the aortic body of the test tool for both researcher and interventionalist was well estimated by curved reconstructions. The researcher achieved a -1.03% under-estimation from the test tool reference value, while the interventionalist achieved unity (0.00%) with the test tool reference value using a curved reconstruction, and a value of - 5.87% below the test tool reference value using a maximum intensity projection (MI?). The interventionalist value was marginally more accurate than that of the researcher, but both were generally very close to the reference value.

The iliac vessel cross-sectional diameter measurement achieved unity (0.00%) with the test tool reference value measured by the researcher, and by 44.19% above the test tool reference value for measurements by the interventionalist (Table7).

The iliac vessel marker distance measurement varied by -1.03% below the test tool reference value for the researcher measurements, and by -1.11% for the interventionalist using curved reconstructions, and by -8.69 using a MI? (TabIe7).

TEST TOOL 2 Aortic body marker distance = 163.0mm. Iliac vessel marker distance = 91.0mm.

Tool configuration: Increased tortuosityof aortic body and iliac vessel.

The researcher tended to marginally over-estimate the cross-sectional diameter of the aortic body by 1.72% above the test tool reference value while the interventionalist over-estimated by 4.02% above the test tool reference value. The researcher value is more accurate than that of the interventionalist (Table6).

Linear marker distance measurement by the researcher was marginally under-estimated at - 0.06% below the test tool reference value, and was almost at unity (0.00%) with the reference value. The interventionalist using a combination of curved reconstructions, MIP's and MPR's returned values of 1.17%, 0.49% and 1.96% respectively, above the test tool reference value (Table 6). These values were also fairly close to unity with the reference value.

The iliac vessel cross-sectional diameter was under-estimated at -2.17% below the test tool reference value by the researcher measurements and by 11.96% above the test tool reference value by the interventionalist measurements (Table 7).

The iliac vessel marker distance measurement by the researcher was not without its problems due to the tortuosity of the vessel, but the final value attained after re-measuring was -5.49% below the test tool reference value. The interventionalist had more difficulty and achieved 11.96% above the test tool reference value using 2-Dimensional point to point measurement, 33.4 1% over-estimation using curved reconstruction, 34.73% over-estimation using MIP's, and 33.52% over-estimation using multi-planar reconstruction (MPR). This demonstrates a high level of error in measurement of cross-sectional diameter and length with test tool configurations of increased tortuosity (Table 7).

TEST TOOL 3 Aortic body marker distance 103.0mm. Iliac vessel marker distance = 62.0mm.

Tool configuration More increase in tortuosity of aortic body and iliac vessel.

The researcher marginally over-estimated the cross-sectional diameter of the aortic body by 0.58% (almost unity) above the test tool reference value while the interventionalist over-estimated by 6.36% above the test tool reference value. The researcher value is more accurate than that of the interventionalist (Table 6).

Linear marker distance measurement for the aortic body was marginally over-estimated by the researcher measurements at 1.46%, and was close to unity with the reference value. The interventionalist using a combination of curved reconstruction, MIP's and MPR's returned values of -2.72%, -1.94% and 1.46% respectively, above and below the test tool reference value (Table 6). These values were also fairly close to unity with the reference value.

The iliac vessel cross-sectional diameter measurements were difficult for both researcher and interventionalist. The researcher value varied by 11.11% above the test tool reference value, whilst the interventionalist value varied by 18.52% above the test tool reference value (Table7).

Linear marker distance measurement by the researcher was almost at unity with 0.97% above the test tool reference value (almost unity), compared with those of the interventionalist measurements at -5.97 (curved reconstructions), -4.35 (MIP's) and -3.71% (MPR's).

It is interesting here that the reverse trend for reconstruction accuracy occurs in that MPR's are more accurate than MIP's, which in turn is more accurate than curved reconstructions (Table 7). b4

Tool configuration: Highly tortuous aortic body and iliac vessel.

The researcher and interventionalist marginally over-estimated the cross-sectional diameter of the aortic body by 0.35% (almost unity) above the test tool reference value, both demonstrating a high degree of accuracy (Table6).

Linear marker distance measurement of the aortic body by the researcher was marginally over-estimated at 0.35%, and was close to unity with the reference value. The interventionalist using a combination of curved reconstruction, MIP's and MPR's returned values of -2.94%, -2.24% and 0.59% respectively above and below the test tool reference value (Table 6). The researcher value was more accurate than that of the interventionalist.

The iliac vessel cross-sectional diameter measurements were reasonably achievable by the researcher at -1.85% below the test tool reference value, while significantly more difficult for the interventionalist. This is reflected in the large under-estimation of -14-94% below the test tool reference value (Table7).

The iliac vessel marker distance measurement made by the researcher was 1.20% above the test tool reference value, whilst that of the interventionalist was quite variant with -5.2% (curved reconstruction), -35.40% (MIP), and 30.20% (MPR). The interventionalist comment was that it was very difficult to measure this curve. Curved reconstructions nonetheless proved to be more accurate than either MIP's or IvIPR's. The researcher demonstrated a high degree of accuracy also using a curved reconstruction method (Table 7). b5

TEST TOOL 5 Aortic body marker distance = 202.0mm. iliac vessel marker distance = 93.0mm.

Tool configuration: High degree of antagonistic tortuosity for Aortic Body and Iliac Vessel.

The researcher and interventionalist marginally over-estimated the cross-sectional diameter of the aortic body by 0.35% above the reference value (almost unity), whilst the interventionalist returned no result for the 2-Dimensional point-to-point measurement (Table 6).

Linear marker distance measurement of the aortic body for the researcher was marginally over-estimated at 0.94% above the test tool reference value and was close to unity with the value.

The interventionalist using a combination of curved reconstruction, MIP's and MPR's returned values of recorded -3.96% (curved reconstruction), -9.46 (sagittal view) and -5.94 (coronal view) for MW's, and -8.37% (sagittal) and -4.26 (coronal) for IvIPR's. The researcher value was more accurate than that of the interventionalist measurement values (Table 6).

The iliac vessel cross-sectional diameter measurements were more difficult for the researcher to achieve at 3.60% above the test tool reference value, but more accurate for the interventionalist at -0.76% below the test tool reference value (Table 7).

The iliac vessel marker distance measurement made by the researcher was much improved at 0.08% (almost unity) above the test tool reference level, whilst that of the interventionalist was quite variant with -3.23% (curved reconstruction), -13.66% (MIP), and 4.73% (MPR) above and below the test tool reference value (Table 7). The researcher value was more accurate than that of the interventionalist.

MAGNETiC RESONANCE IMAGING TEST TOOL 1 Aortic body marker distance = 213.0mm. Iliac vessel marker distance = 99.0mm.

Tool configuration: Shallow tortuosity of aortic body and iliac vessel.

The researcher over-estimated the cross-sectional diameter of the aortic body by 0.17% above the test tool reference value while the interventionalist over-estimated by 5.55% above the test tool reference value. The researcher value was more accurate than that of the interventionalist

(Table 8).

Linear marker distance measurement of the aortic body for both researcher and interventionalist was well estimated by curved reconstructions. The researcher achieved under-estimation from the test tool reference value at -1.41%, while the interventionalist achieved 1. 41% above the test tool reference value (Table 8). The researcher and interventionalist values were equally accurate, albeit below and above the test tool reference value respectively.

The iliac vessel cross-sectional diameter measurements varied by 1.51% above the test tool reference value for the researcher and by 23. 99% above the test tool reference value for the interventionalist measurements (Table9).

The iliac vessel marker distance measurement varied by -1.41% below the test tool reference value for the researcher, and by 4.44% above the test tool reference value for the interventionalist measurements using curved reconstructions (Table 9).

The researcher generally attained significantly greater accuracy than the interventionalist and measurement of cross-sectional diameter proved to be difficult for the interventionalist.

Tool configuration: Increased tortuositv of aortic body and iliac vessel.

The researcher tended to marginally over-estimate the cross-sectional diameter of the aortic body by -0.29% below the test tool reference value (near unity) while the interventionalist over-estimated by 5.40% above the test tool reference value (Table 8). The researcher value was more accurate than that of the interventionalist.

Linear marker distance measurement of the aortic body by the researcher was 0.00% variance (unity) with the test tool reference value, whilst the interventionalist achieved a significant under-estimation of -40.49% below the test tool reference value (Table 8).

The curvature of the vessel and its appearance on the images was such that no suitable curve or manipulation could be performed that would give confidence in the reading.

The iliac vessel cross-sectional diameter measurements varied by 9.49% above the test tool reference value for the researcher and by -12.76% below the test tool reference value for the interventionalist (Table 9). This was a difficult curve to be resolved, and was duly reflected in the accuracy and spread of the results.

The iliac vessel marker distance measurement was better represented as the researcher achieved -0.33% below the test tool reference value (almost unity), and the interventionalist -1.87% below the test tool reference value (Table 9).

Both researcher and interventionalist were unable to improve on the value obtained for iliac vessel cross-sectional measurement, but accurate linear length measurement was shown to be possible.

TEST TOOL 3 Aortic body marker distance = 103.0mm. Iliac vessel marker distance 62.0mm.

The researcher marginally over-estimated the cross-sectional diameter of the aortic body by 2.08% over the test tool reference value while the interventionalist over-estimated by a higher 9.57% above the test tool reference value. The researcher value was more accurate than that of the interventionalist (Table 8).

Linear marker distance measurement on the aortic body for the researcher was marginally over-estimated at 0.97% above the test tool reference value and was close to unity with the reference value. The interventionalist achieved a value of 1.75% above the test tool reference value. The value was also fairly close to unity with that of the reference value (Table 8).

The researcher iliac vessel cross-sectional diameter measurements were accurately obtained with -0.12% below the test tool reference value, while the interventionalist achieved a gross over-estimation of 56.60% above the test tool reference value. This proved to be a difficult reading for the interventionalist (Table 9).

The iliac vessel marker distance measurements made by the researcher over-estimated by 0.8 1% above the test tool reference value. The interventionalist was able to achieve 3.7 1% above the test tool reference value (Table 9). The researcher was more accurate in the measurements compared to the interventionalist.

Tool configuration: Highly tortuous aortic body and iliac vessel.

The researcher and interventionalist under-estimated the cross-sectional diameter of the aortic body by -6.00% below the test tool reference value and by -12.92% below the test tool reference

value (Table 8).

Linear marker distance measurement on the aortic body by the researcher was marginally under-estimated at -0.12% below the test tool reference value, while the interventionalist trailed closely behind with -0.24% below the test tool reference value (Table 8).

The researcher value was marginally more accurate than that of the interventionalist, but both values were close to unity (0.00%).

The iliac vessel cross-sectional diameter measurements were also reasonably difficult for the researcher and interventionalist with over-estimations of 13.41% above the test tool reference value for the researcher measurements and 9.05% above the test tool reference value for the interventionalist measurements (Table 9).

The iliac vessel marker distance measurement made by the researcher was 0.20% above the test tool reference value (almost unity), whilst that of the interventionalist was slightly greater at 2.20% above the test tool reference value (Table 9). The researcher value was slightly more accurate than that of the interventionalist. 7D

The researcher marginally under-estimated the cross-sectional diameter of the aortic body by -0.23% below the test tool reference value (almost unity), while the interventionalist value was much greater at -13.49% below the test tool reference value (Table 8).

Linear marker distance measurement of the aortic body for the researcher was marginally under-estimated at -0.79%, and was close to unity with the reference value. The interventionalist achieved -6.19% below the reference value (Table 8). The researcher values were more accurate than that of the interventionalist.

The iliac vessel cross-sectional diameter measurements were marginally under-estimated by the researcher with -0.76% below the test tool reference value, but was slightly more difficult for the interventionalist with 2.5 1% above the test tool reference value (Table 9).

The iliac vessel marker distance measurement made by the researcher was under-estimated at -2.90% below the test tool reference value, while the interventionalist achieved a greater accuracy with -1. 08% below the test tool reference value (Table 9). -It

MAGNETIC RESONANCE IMAGING TESTING WITH VARIABLE CONFiGURATIONS The MIRI images were generated using a pulse sequence called Fast Low Angled Shot (FLASH).

The images generated were recorded measured and evaluated.

FLASH AORTIC TOOL 1-AORTIC BODY The researcher using curved reconstructions was able to achieve 0.00% variation from the test tool reference value (unity) while the mterventionalist achieved -1.46% below the test tool reference value using curved reconstruction and -5.51% below the test tool reference value using

MIP's (Table 10).

FLASH AORTIC TOOL I-ILIAC VESSEL

The researcher using curved reconstructions was able to achieve 0.78% above the test tool reference value while the interventionalist achieved 0.10% above the test tool reference value using curved reconstruction and -6.50% below the test tool reference value using MIP's

(Table 10).

FLASH AORTIC TOOL 2-AORTIC BODY The researcher using curved reconstructions was able to achieve 0.16% above the test tool reference value while the interventionalist achieved 0.52% above the test tool reference value using curved reconstruction and 0.52% above the test tool reference value using MIP's

(Table 10).

FLASH AORTIC TOOL 2-ILIAC VESSEL The researcher using curved reconstructions was able to achieve 0.00% variation from the test tool reference value (unity) while the interventionalist achieved -0.95% below the test tool reference value using curved reconstruction (almost unity) and -7.16% below the test tool reference value using MIP's (Table 10). 72.

FLASH AORTIC TOOL 3-AORTJC BODY The researcher using curved reconstructions was able to achieve 1.59% above the test tool reference value while the interventionalist achieved 4.59% above the test tool reference value using curved reconstruction and -1.91% below the test tool reference value using MW'S

(Table 10).

FLASH AORTIC TOOL 3-ILIAC VESSEL The researcher using curved reconstruclions was able to achieve -0.91% below the test tool reference value (almost unity) while the interventionalist achieved an average of -5.35% below the test tool reference value using curved reconstructions with minimal and maximal values of -10.1%, -5.05% and -1.01% below the test tool reference value respectively.

Further manipulation using MIP's gave an average of -10.4% below the test tool reference value, with highly fluctuant minimal and maximal values at -28.28% and -5.05% respectively below the test tool reference value (Table 10).

FLASH AORTIC TOOL 4-AORTIC BODY The researcher using curved reconstructions was able to achieve 0.17% below the test tool reference value (almost unity), while the interventionalist achieved 2.33% above the test tool reference value using curved reconstructions and 2.84% above the test tool reference value using

MIP's (Table 10).

FLASH AORTIC TOOL 4-ILIAC VESSEL The researcher using curved reconstructions was able to achieve -1.89% below the test tool reference value while the interventionalist achieved 1.35% above the test tool reference value using curved reconstructions and -5.00% below the test tool reference value using MIP's

(Table 10). 7-3

FLASH AORTIC TOOL 5-AORTIC BODY The researcher using curved reconstructions was able to achieve -1.3 1% below the test tool reference value while the interventionalist achieved an average of -1.67% below the test tool reference value using curved reconstructions with minimal and maximal values of -2.02 and -1.01% below the test tool reference value respectively.

Further manipulation using MW's gave an average of -4.19% below the test tool reference value with minimal and maximal values of -7.07%, -3.03% and -% -2.52 respectively (Table 10).

FLASH AORTIC TOOL 5-ILIAC VESSEL The researcher using curved reconstruction was able to achieve 1.67% above the test tool reference value while the interventionalist achieved an average of 10.90% above the test tool reference value using curved reconstructions with higher variation in minimal and maximal values of -0.5 1%, 15.38% and 16.67% above and below the test tool reference value respectively.

Further manipulation using MIP's gave an average of 4.49% above the test tool reference value with more variation in minimal and maximal values at -2.05%, -1.28% and 16.67% above and below the test tool reference value respectively (Table 10).

THE EFFECTS OF DISTANCE FACTOR ON THE ACCURACY

OF MEASUREMENTS OBTAINED ON THE AORTIC MODEL

Distance factor is applied in MR1 to reduce the detrimental effects of cross-talk between adjacent slices of an image reconstruction. Failure to implement this factor on volume scans can result in a reduction of signal-to-noise values and a perceptible level of image degradation at image boundaries. Volume scans utilise this flictor as a general component of the overall protocol construction. The effects of its has yet to be quantified in terms of its effects on z-axis measurement accuracy. Two experiments were conducted to evaluate these effects using the test model. A known distance was applied to the body of the aorta and also one for the iliac vessel. 7k

A series of MRI scans were performed on the test object with variations of distance factor ranging from 0%, 20%, 40%, 60%, 80%, and 100%. The model was set at 140mm for the aortic body and 62mm for the iliac vessel. The resultant images were measured recorded and evaluated

(Tables 11-12).

The results obtained with the aortic body of the first model showed a 0.43%, 1.2 1%, 1.64%, 3.29%, 2.21% and 0.64% increase in measurement value above the test tool reference value

(Table 11).

The iliac vessel demonstrated a 0.16%, 4.03%, 3.71%, 4.52%, -2.1% and 2.42% general increase above and below the test tool reference values set (Table 11).

The distance markers were reset to 114mm for the aortic body and 49 mm for the iliac vessel for the second test. The configuration was more tortuous than that used before. The test object was imaged and the readings measured recorded and evaluated (Table 12).

The results demonstrated a general under-reading of values obtained on the aortic body with variations in the range of-1.49%, -0.79%, -0.70%, -1.05%, -1.05%, and -0.61% below the test tool reference value respectively.

The iliac vessels showed a wider range of variation and generally over-read in the range of 12.71%, 10.82%, 7.35%, 12.65%, 6.94% and 10.20% above the test tool reference value.

MEASUREMENT DEVIATION N MULTI-PLANAR

RECONSTRUCTIONS (M.P.R' s) It is of the greatest importance to manipulate an image generated from raw data to form an multi-planar reconstruction (MPR) or a 3-Dimensional image block, so that the subject being measured has minimal elongation or foreshortening. There is nonetheless a difficulty in judging the best reconstruction or orientation of a particular image volume slab, since the absolute measurement value of the subject is initially unknown, although it may have been previously evaluated as the result of an ultrasound scan, CT scan, DSA examination,or measurement from a transverse section from a series in the same MRI examination.

This part of the experiment endeavoured to demonstrate how the distance variations may manifest in an object of known distance, with images gained from different reconstruction planes. It can be appreciated that there are variances that can be introduced as a resu]t of the projection used. These are due to inconsistencies of measurement and the inability to produce highest quality MPR's and curved reconstructions that may result in inaccuracies of measurement and the consequent generation of sub-optimal further images. The distances are measured from the bright mid-point of one oil marker to another. Where a curved reconstruction has been used, a straight line was drawn between the two bright points of the oil marker.

In extremely tortuous vessels, a curved image may be used from a curved reconstruction. This in itself is a limitation of the measuring software since no accurate measurement can be ascribed to the line and an estimate may have to be used. The variations of distances measured are detailed in Table 13 (aortic body measurement) and Table 14 (iliac vessel measurement).

Aortic Distance Set (mm) Recorded Distance (mm) Percentage Deviation 191.0 196.4 + 2.83 191.0 192.5 + 0.79 191.0 182.4 -4.50 191.0 192.3 0.68 191.0 189.7 -0.68 191.0 194.0 + 1.57 Table 13 -Variations in Aortic Body measurement.

Iliac Vessel Distance (mm) Recorded Distance (mm) Percentage Deviation 74 63.5 -5.50 74 76.2 + 1.15 74 66.7 -3.82 74 77.3 1.73 Table 14 -Variations in Iliac Vessel measurement.

There is a general spread of -4.50% to 2.83% (7.33% total) above and below the test tool reference value. The iliac vessel exhibits a range of -5.50% to 1.73% (7.23% total) relative to the test tool reference value (Tables 13-14).

The drift in accuracy can be minimised by measurement along an axis that is parallel to that of the vessel to be measured. Manipulation of a 3-Dimensional image block allows such optimisations to become achievable. Conversely, detraction from this principle will result in more spurious readings to be obtained, which in the case of an unevaluated vessel, these results may be taken as actual measurement values.

The types of difficulties encountered are have been indicated within this specification and gives an insight of how more accentuated deviation may occur with a more tortuous tool configuration, that is, with more accentuated curvature of aortic body and iliac vessel.

EVALUATION OF FAST LOW ANGLED SHOT (FLASH) TECHNIOUES

AND VARIATIONS IN AORTIC BODY AND ILIAC VESSEL MEASUREMENTS

AS A RESULT OF 3-DIMENSIONAL CONSTRUCTION SOFTWARE In this test the test tool was configured so that the aortic body had a marker distance of 194 millimetres and the iliac vessel section a length of 99 millimetres. The test tool was placed into an MRI imaging machine and images were generated using a FLASH imaging sequence. The images were recorded measured and evaluated. The results are shown in Table 15.

The image is moved to an orientation of choice where it is deemed to give the best measurement results from the reporters' knowledge of anatomy and experience. The image is measured for length and then the image is turned to another position of choice, re-measured and repeated until a range of measurements are obtained from a number of images viewed in preferred planes and ones which are deemed to give the best results.

The variations in measurements for the aortic body section above and below the test tool reference value ranged from 1.57%, -2.62%, -0.68%, 0.68%, -4.50%, 0.79%, and 2.83% respectively. The curvature of the aortic body section was minimally tortuous.

The variations in measurements for the iliac vessel section above and below the test tool reference value ranged from -24.24%, 18.48%, -32.62%, -23.03%, and -35.86% respectively.

The curvature of the iliac vessel was moderately tortuous.

The total spread of measurement accuracy deviation in the iliac vessel section was 54.34%,.

which is unacceptable for radiological measurement evaluation. It is worth noting in cases of high levels of vessel tortuosity it is sometimes difficult to see both distance markers on both MRI and CT measurement platforms, and that the default thickness settings of 3mm with a gap between slices of 3mm are considered wholly inadequate by the inventor for the measurement of vessels.

As a consequence of matching the measurements obtained conventionally to those of known value, there exists a variation and inaccuracy in using default settings. The use of a thick section MPR from 100% to 1000% enables the visualisation of both distance markers and the ability for correct perpendicular line-up of the slab, for a curved reconstruction to be accurately drawn and appropriately measured. This method of image manipulation gives accurate and consistent distance measurements.

In this detailed study it has become evident that configuring of the aortic body and iliac vessel sections can result in a minimum of two types of measurement behaviour. Firstly, the thicker aortic body section at low levels of vessel curvature or tortuosity can be made to demonstrate quite acceptable levels of measurement conformancy using 2-Dimensional and 3-Dimensional software programs. The test tool shows its strength as a reference tool and is able to imaged on multiple imaging modalities with a high level of measurement compliance with results generally falling within a band of no more than plus or minus 5% variation above or below the test tool reference value.

Increases in curvature show a progression towards wider variance in cross-sectional and length measurements with unacceptably high levels of variance (above 10%) above and below the test tool reference value.

Variations appear to be much more accentuated in the smaller diameter measurements of both diameter and length.

Further increased curvatures in opposing or opposite complementary or near complementary planes results in a higher level of measurement error which can rise to as much as 56.60% above the test tool reference value for diameter and to a point of not being able to be measured for length. Lesser manifestations may demonstrate variations on MRI to vary between as much as -35.86% to 18.48%.

METHODS OF EVALUATION

DIGITAL SUBTRACTION (DSA) AND RADIO-FLUOROSCOPY (RF) IMAGES Digital Subtraction Angiography (DSA) and Radio-Fluoroscopy (RF) image testing requires fluoroscopic images to be taken at four positions around the centre of the test tool. Where the measurement tubes extend outside of the base frame area, the tool should be positioned so that the central point of the measuring tubes are in the centre of the field of the image intensifier, in order to reduce image distortion to a minimum. The distance of the object to the intensifier head should also be kept to a minimum (around 30 centimetres) to reduce magnification of the image, but to allow for freedom of table movement without having to lower the imaging table. The measurement tubes can be made in a variety of diameters, lengths and degrees of tortuosity or shapes, in order to fully test the imaging modality.

The base frame is typically loaded with a single vertical column, although more than one may be used by preference, or to achieve a particular objective. The vertical column is placed and locked into the frame using the appropriate locking screws and the nearest available hole(s) in the longitudinal section of the base frame. Where more than one vertical column is used, each may be placed at the extreme points of the frame to allow for maximum tool extension(s) and greater variety of tool shapes. The positioning of the measurement tube(s) within the recesses of the vertical column(s) provides a higher degree of variation in the final generated images since the position, tortuosity and degrees of variation for each shape of measuring tube is further variable by a factor of eight times, due to them being located into the octagonal shaped recesses of the vertical columns. This reflects in the shift in accuracy for this method of measurement, which is more variable with the highest degrees of tortuosity, as would be expected.

Once the measuring tube is located into the vertical column, it is locked into place by the union of a retaining bolt and washer. More than one measurement tube may be used on each face of the vertical column and this may add to the information gained from each set of images. -Ic'

The assembled unit is the placed onto the imaging table and the "C" arm of the DSA or RF imaging unit is moved into position so as to be in the centre of the measurement tubes, or in the middle of the area traversed by the measurement tubes. The intensifier head is fully retracted to its highest point in the "C" arm and the table is raised in height to a point about 30 centimetres from the intensifier head to minimise magnification, but allow for free movement of the tool in the longitudinal and transverse table directions without the likelihood of impacting the intensifier head, or having to lower the height of the table to avoid it.. The tool is checked for centralisation both longitudinally and transversely in the imaging field of the intensifier.

A series of images is taken using the fluoroscopic single image mode of the DSA or RF apparatus. The recommended views are a postero-anterior (PA) 0 degrees, a -30 degree PA, a +30 degree PA, and a lateral view. The images are written to the hard drive of the respective modality for archiving, labelling, measurement, and networking purposes.

In DSA or RF imaging, only one aspect of a test object is recorded due to the 2-Dimensional nature of the imaging process. The aspect of the test object imaged is that which occupies a plane parallel to the input field of view of the modality, and the ratio of magnification of the resultant image is the product of the object distance (in centimetres) divided by the tube to intensifier distance (in centimetres) multiplied by 100 to bring it to a percentage.

The PA 00, PA +30 , and PA 3O0 are thus reflective only of the lateral (or right to left sided) surface of the test model. This condition changes to the antero-posterior aspect on the Lateral view since the test model is being viewed at 900 -600 when compared to the other three views.

The generated images are viewed and it is seen that the central wire passing through the centre of each measurement tube has regular expanded parts on its outer surface that relate to the I centimetre markers throughout the length of the tube. The length of fluid column of the measuring tube appears as a more attenuated and delineated boundary along the inside of the measurement tube(s) and the interior surface of the measuring tube to the ends of the imaging volume. The measuring tubes have reference internal diameters, external diameters, test lengths and copper wire reference points.

The internal copper markers display the 1 cm radio-opaque markers as black on the DSA or RF image and appear as regularly spaced dots along the length of the measurement tube(s).

At varying points along the length of the test tool, the measurement of these calibrated distances will vary for either one or both of the following reasons. Firstly, the acquisition will present the I cm distance generally as a multiple, but less often a fraction of the 1 cm, due to the fact that the test tool is not directly against the image intensifier end of the machine. In fact according to the principle of magnification of objects, this should logically represent us with a situation where the distance measured should be in excess of 1 cm. This does not always tend to be the case since the image intensifier has a maximum input field of view of 38 cm.

The attenuation pattern from the incident X-ray beam that interacts with the test object will fall upon the input side of the image intensifier and will be scaled to the output size of the monitor screens. This occasionally results in a marginally smaller image to be formed on the viewing screen. The overall effect is that this smaller degree of magnification causes 1 cm graduations to be represented as a minified version of its true size, and which has experimentally been shown to vary between 8 to 10 mm. This is not a problem since a ratio calculation may be applied to calculate the true dimensions of the test object. Secondly, there will always be a value of subject-to-intensifier distance since the measuring tubes will not always be in contact with the intensifier head.

The important aspect to incorporate into any distance or cross-sectional measurement is to obtain an average of three readings, and to measure a section parallel to the longitudinal profile of the measuring tube in length measurements, and to measure a section perpendicular to the measuring point for cross-sectional measurements.

In the case where a 1 cm distance between the centre points is measured as 0.9 cm then the ratio used is defined by the actual distance divided by the measured distance on the image. In said case 10/9= 1.11 recurring. The distance will then be measured between the middle points of the two distance markers on the wire on the interior of the measuring tube.

The measured distance in millimetres will then be multiplied by the value of the ratio and this will be the final measured distance of the copper wire markers.

For cross-sectional diameter, the ratio of the internal or external diameters can be related back by application of the magnification to arrive at the actual cross-sectional diameter.

The process should be carried out for a range of other measurement tubes with varying length and cross-sectional diameters, so that a true picture of variance for certain conditions may be built up.

COMPUTED TOMOGRAPHY (CT) IMAGES Imaging in the computed tomography (CT) scanner is generally fast and easily repeated. The images generated are rapidly evaluated in less tortuous tool configurations than for the highly curved and elaborately bent forms of the more complex tool shapes.

The said tool that had been used for the DSA testing now can be directly transferred to the imaging table of the CT scanner without any variation in setup.

The tool is aligned to the longitudinal axis of the table and midway across the centre of the aperture. The positioning lasers are used to position the tool so that the x-axis (horizontal) lasers cut the middle of the height of the tool and that y-axis lasers cut the middle of the longitudinal section of the test tool from one end to the other. When this has been achieved, the test tool will be in the iso-centre of the imaging field. The tool is positioned for a planning image (scanogram or surview) and the image generated is used to plan a helical or spiral acquisition covering all aspects of the test tool, and in a reconstructed field of view (FOV) that is able to be set for all of the other imaging runs. This ensures that there will be no variation of the image size on the generated images for all test tools.

To ensure good image quality on post-processed images, a table interval of 50% is used in order to avoid stair-step artefact and enhance multi-planar viewing.

The scan is acquired and the study ended following adequate scan coverage. The images are selected and the loaded into the Multi-Planar Reconstruction (MPR) platform. The images are typically viewed in a set of six images on the post-processing display. It is important to select the best plane to show the position of the copper markers.

A good starting point, due to curvatures of the measurement tool, is to view the test object in profile using a sagittal reconstruction, and a good set of images will allow the visualisation of the entire length of the measuring tube along with the markers on the copper wire.

It is often difficult to visualise the entire measurement tube and markers because of the in-plane and out-of-plane effects of the curvatures of the measuring tubes.

On axial images, the calibrated markers appear as highly attenuating (streaking on image due to beam hardening effects) intermittent bands appearing along the length of the measurement tube.

The position of this will alter depending on the course of deviation of the tool throughout the translation process of the scanner.

The images that are selected are complete as best achievable for the measuring tube central wire markers and both ends of the imaging volume. This process can be lengthy at times due to the types of curvatures built into these tubes, but generally the best results are obtained from angulation of the planes in two out of the three orthogonal directions. It is sometimes not possible to show all relevant parts of the imaging volume, so these actually demonstrate the limitation of the software to demonstrate or visualise the test object in its entirety.

The software measurement tools are used to trace a line from one end of the imaging volume to the other of from one set of copper markers to another somewhere along the length of the wire.

This is measured as part of the software function and this can be compared to the known reference value for that particular measuring tube.

The cross-sectional diameter can be obtained using the same method and where preferentially, using an axial image, a line may be drawn from one outer point on the outer wall of the measurement tube, through the central axis of the copper wire, to a corresponding and diametrically opposite point on the outer wall of the tube opposite.

This will give the value of the cross-sectional diameter which can be compared to the reference value for that particular measurement tube.

MAGNETIC RESONANCE (MR) IMAGES Imaging in the magnetic resonance (MR) scanner is generally a much longer process, but easily repeated. This is because of the small amount of parallel hydrogen atoms that actually contribute to the image producing process. Consequently, imaging sequences take in the order of minutes to produce reasonably high signal-to-noise ratio images that may be used for measurement purposes.

The images generated are rapidly evaluated in less tortuous tool configurations than for the highly curved and elaborately bent forms of the more complex tool shapes, similar to CT, but the volume image block manipulation capability of the software, gives it an advantage over the CT post-processing, to the effect that it is arguable that MRI is marginally better at resolving high tortuosity measurement tubes than is possible on CT software platforms.

The said tool that had been used for the MRI testing now can be directly transferred to the imaging table of the CT scanner without any variation in setup. The inherent construction of it allows for it to be transferred into the magnetic environment without any safety related changes.

The tool is aligned to the longitudinal axis of the table and midway across the centre of the aperture. The positioning lasers are used to position the tool so that the x-axis (horizontal) lasers cut the middle of the height of the tool and that y-axis lasers cut the middle of the longitudinal section of the test tool from one end to the other. The centring laser is then positioned to the middle of the test tool, and the table advanced so that the tool comes to rest in the middle of the scanners bore and at its iso-centre.

A three plane localiser is chosen to generate images in transverse, coronal and sagittal planes.

Typical pulse sequences used are spin echo (se) or Fast imaging at Steady Precession (FISP).

The generated images are used to plan volumetric and slice selective acquisitions covering all aspects of the test tool, and in a reconstructed field of view (FOV) that is able to be set for all of the other imaging runs. This ensures that there will be no variation of the image size on the generated images for all test tools.

The main acquisitions used are typically a T2-weighted transverse (axial) slice selective block with its distance factor set at zero to ensure contiguous sections, and a T2 weighted turbo-spin-echo (tse) volume acquisition.

To ensure good image quality on post-processed images, a distance factor of 0% is used in order to avoid spurious measurement variations in the final measurement results that may have an effect when using the manufacturer manipulation software packages such as multi- planar reconstruction (MPR), curved reconstruction, and maximum intensity projections (MIP) or other resident re-construction programs. c4

The trade-off with using a 0 % distance factor is that there may be cross-talk between adjacent slices of the test object that may cause an increase in signal-to-noise effects at the boundary between the two sections.

The scan is acquired and the study ended following adequate scan coverage. The images are selected and the loaded into the Multi-Planar Reconstruction (MPR) platform. The images are typically viewed in a set of four images in three orthogonal planes, th one section of the screen occupied by the 3-Dimensional block that may be selected and tilted in any position, and which assists in the tracing of the central wire on highly tortuous measurement tubes. It is important to select the best plane to show the position of the copper markers, as in the case of CT. A good starting point similarly, due to the curvatures of the measurement tool, is to view the test object in profile using a sagittal reconstruction. A good set of images will allow the visualisation of the entire length of the measuring tube along with the markers on the copper wire.

It is often difficult to visualise the entire measurement tube and markers because of the in-plane and out-of-plane effects of the curvatures of the measuring tubes, but the 3-Dimensional block will aid this process. The images that are selected are complete and as best achievable for the measuring tube central wire markers and both ends of the imaging volume. This process can be lengthy at times due to the types of curvatures built into these tubes, but generally the best results are obtained from angulation of the planes in two out of the three orthogonal directions.

It is sometimes not possible to show all relevant parts of the imaging volume, so these actually demonstrate the limitation of the software to demonstrate or visualise the test object in its entirety. The software measurement tools are used to trace a line from one end of the imaging volume to the other of from one set of copper markers to another somewhere along the length of the wire. This is measured as part of the software function and this can be compared to the known reference value for that particular measuring tube.

The cross-sectional diameter value can be obtained by measuring from a point on the internal surface of the measuring tube at the bright fluid boundary, across to pass through the central wire (dark), and across further to the bright fluid boundary on the internal surface of the tube diametrically opposite. The positioning of this will alter slightly depending on the course of deviation of the tool shape and the selected plane of viewing. (5

The length of the measurement tube can be traced using the software tool, from bright end of the imaging volume on a course parallel to the dark image of the central wire, to the other bright end of the imaging volume. The software will register the distance value for that particular measurement tube and the value for cross-sectional diameter can be compared to the known internal diameter of the tube, and the length values compared for parity.

The images of the test tool may be enhanced by sliding it into the MRI water enclosure and subsequently imaging the tool contained within. Due to the signal given off by the surrounding water, the media external to the tube will appear as a bright surrounding to the measurement tube. The fluid media contained within the measurement tubes will be brighter in appearance, whilst the plastic of the tube little or no discemable MRI signal, and so will appear as a black ring. The outer surface of this may be measured in a manner similar to that of the internal diameter, and the values may be compared for measurement accuracy.

The length of the measurement tube may be plotted and calculated by the method outlined previously.

NUCLEAR (ISOTOPE) IMAGING The module for measurement of isotope imaging requires to be engaged into the base plate in the prescribed manner. The tool configuration should be adequately equipped for single planar acquisitions or maximally adapted to allow for tomographic testing for SPECT and PET type scan sequences.

The plastic isotope holding module(s) should be charged typically with 15 MBq (Mega Becquerels) activity of 99m Tc (99 metastable Technetium) in a blue tinted solution (methylene blue), to aid filling. The steel tube should then be located and locked into the lead shielding insert of the respective test module(s).

The test tool is placed onto the imaging table on a line that runs longitudinally down the centre of the table, and at a point at the centre of the imaging area of the camera.

A high definition collimator should be used in order to produce the highest resolution images of the imaging tool apertures at an activity that requires typically three minutes to acquire 400,000 counts.

The head of the gamma camera is lowered to a very short distance (less than 10 millimetres) from the uppermost part of the accessory module and an acquisition of 400 Kilocounts is made.

When the acquisition is terminated, the images are evaluated, measured and compared with the reference values typical of the accessory modules. Any deviation from the accuracy of measurement may be taken as an indication of the levels of measurement compliancy for that particular gamma camera.

In the case of tomographic acquisitions, the images should only be evaluated in the horizontal and vertical planes. This will ensure that geometrical distortions are minimised and that the magnification factor remains constant for the acquisition.

COMPUTED RADIOGRAPHY (CR) IMAGES The base frame may be modified to allow for measurement of computed radiography (CR) images, by the slotting in of one of two additional modules, in the form of a perspex imaging block. The polymer based block is designed to be a drop in module for the base frame, so consequently there will be no retaining mechanisms.

The polymer based block is constructed from perspex (RTM), acrylic or other suitably non-magnetic, radiolucent, durable, and transparent material. It consists essentially of an oblong block of typical dimensions 360 millimetres length by 198 millimetres width and 25 millimetres thickness.

On the underside of the block is an arrangement of radioopaque markings that when viewed from above describe a number of functional markings, lines and edge indicators.

The lines form a square on the bottom aspect of the base of 350 millimetres length by 190 millimetres width. A diagonal line is drawn from each corresponding corner to form four triangular sections. Another two lines are drawn from the midpoint of each edge to the centre of the base dividing the triangular sections into two. This in itself forms smaller triangular areas across the base area. Along each of these bisecting lines and extending to the edges of the plate are linear scales measured in metric or Imperial sub-divisions of a metre.

Typically in the case of a metric scaled base, these subdivisions would be in millimetres and centimetres and extending from the centre point at zero radially to their respective maximum values. At each of the four corners of base at a point 90 millimetres above and below the longitudinal (or horizontal) centre line and 175 millimetres to the left and right of the tiansverse (or vertical) centre line are four corner identifiers, each set comprising right angled lines of 30 millimetres length. These will delineate the corners for an X-ray field collimation area test.

In every other triangular section of the base and inlaid into thepolymer substance are functional test units for assessment of image distortion, measurement of resolution, and sensitometric type testing of the image plate recording system In practice, the base frame is typically placed onto the surface of a 35 centimetre by 43 centimetre imaging plate, at the centre longitudinally and transversely, and the first accessory imaging block is laid into it. The frame serves as a reference point for the test, but the module should be placed in the middle of the imaging plate and positioned so that the vertical central ray is at the centre of the test module. A focus to imaging plate distance of 100 centimetres should be used, and the aperture on the light beam diaphragm set to include all areas of the perspex imaging plate.

A radiographic exposure is made and this should be in the order of 50 Kilovolts (Ky) and 2 milliAmpereseconds (mAs). The imaging plate is read by the CR reader, whist another imaging plate is placed under the imaging tool. The radiographic exposure is repeated with 60 Ky and 2mAs, and this imaging plate is read, the same is repeated for 70 Ky, 2 mAs, and 80 Ky, 2 mAs.

The process may be repeated for 50 Ky, 2mAs, then 50 Ky, 4 mAs, then 50 Ky, 8 mAs, and 50 Ky, l6mAs.

LIGHT BEAM DIAPHRAGM TESTING

The images produced will give information regarding the setting of the emergent beam from the light beam diaphragm. If the light beam is delineated within the confines of the four corner angulated markers, and the field of irradiation on exposure causes the exposure field to be recorded outside of the images of the markers, then it indicates that modification is required.

This may relate to extra-focal radiation from the target, mis-aligned light beam diaphragm, or warped x-ray tube filament.

SPATIAL LINEARITY IN X-AXIS AND Y-AXIS OF IMAGING FIELD

Using reference to the 1 centimetre radio-opaque markings on the imaging block, the distance between graduations may be measured using the electronic callipers of the measurement software on the quality assurance (QA) station. Since the imaging block is in contact with the imaging plate, then distortion should be at a minimum. Where inconsistencies exist in the radiation field, causing the field to be non-centralised, there will be an increase in the separation values that lies out of the general range obtained, and this will be reflected in the direction of de-centralisation of the beam. This will identify where correction should be made.

RESOLUTION

The module contained in section 3 of the imaging block contains a block that is embedded into the underside of the block, and containing a number of line pair gauge modules for determination of resolution of the imaging system. The image can be read and the number of visible line pairs noted and the resolution calculated by normal medical physics methods.

IMAGE CONTRAST

The aluminium step wedge inlaid into sector 7 of the imaging plate will allow sensitometnc data to be derived in the conventional maimer by the change in illumination across adjacent boundaries of the wedge steps on a printed film of the image, of across the screen of the workstation. The values can be plotted and an indication of the imaging plate response to the x-ray beam may be appreciated by virtue of its response to changes in Ky and mAs.

UNIFORMITY OF X-RAY FIELD

The imaging block will be uniformly irradiated with X-radiation that will confer a general level of grey scale or darker intensity on the resultant image. Variations of this general level of grey scale intensity across the imaging plate will indicate lack of uniformity in the x-ray beam.

This may be investigated more fully by checking the light transmission through a printed film image with a densitometer.

IMAGE DISTORTION

Embedded into sectors 2, 4, 6 and 8 are modules containing moderate attenuation compound that is denser than perspex. The material is shaped into a triangle, a square, and a circle. The triangle has known reference values of all of its sides, as is the case with the square. The circle has a known reference diameter. The position of these modules is such that each one is a mirror image of its opposite counterpart, except that that counterpart is to the opposite side of the longitudinal or transverse line. This will assess distortion of the X-ray field, and inconsistencies of linearity in specific areas of the beam.

THE SECOND IMAGING MODULE FOR MEASUREMENT EVALUATION

OF COMPUTED RADIOGRAPHY (CR) The second tool is based on a measuring tube concept in which the longitudinal (horizontal), transverse (vertical), and oblique projection of X-radiation from the effective focal spot wiLl be assessed for its effect of elongation on the resultant computed radiography image.

The accessory module may be dropped into the base frame, at a similar point to the CR imaging block. The frame serves as a reference point for the two tests, but each of the modules should be placed in the middle of the imaging plate and positioned so that the vertical central ray is at the centre of the test module. A focal to imaging plate distance of 100 centimetres should be used.

Testing and evaluation is similar to that in the first imaging module. The testing capabilities of this allow for linearity testing and for distortion of images due to tube wear or changes in equipment setup.

The images produced from this module can be used as reference standards for the testing of measurement accuracy of images viewed on teleradiography networks, such as the Picture Archive and Communication System (PACS). Use of the measurement tubes can give a comparative value to those measured by the imaging block tests. The use of measuring tubes can be further verified by imaging them on computed tomography apparatus and comparing values.

These may then be compared to the actual reference values for the particular measuring tubes.

The tube and image block reference values can be compared to those measured on quality assurance stations, modality specialist workstations, reporting workstations, clinical review, diagnostic workstations, and CR image browsers. cit

SUBMISSION OF CLAIMS IN RESPECT OF PATENT APPLICATION

NUMBER 0709069.9 AND REFERENCE NUMBER RIT/2007 The following claims are submitted as part of the patent application with the above application number and under the applicant name of Cameron Nigel Glenville Carpenter.

The contents of the following claims section is contained also within the main body of the

descriptions contained in the patent application.

Claims

1. Radiological image testing apparatus comprising a base frame(s),vertical colwnn(s), tubular measuring tube(s), linear reference tool(s), measurement devices accessory base plate, tool supporting block accessory module, and specialised imaging 2-Dimensional, 3-Dimensional and z-axis testing mo4uic, in that the baseiramefunctkons as the first point of a progressive modular imaging system that can be assembled quickly for convenience and made to lImction as a cross-sectional-diameter and linear, curved or otherwise defined-distance-verification tool.

2. Appa ailii Cithlbëiëi ihe apparatus compes individually configured sections to enable specific testing of an imaging modality and subsequent image evaluation using manulàcturer modality software packages, the reference value(s) of functional tools therein contained in testing modules, to provide a comparison of measurement accuracy of manufacturer software against that of the reference modules.

3. Apparatus as claimed in Claim!, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of digital subtraction imaging apparatus (DSA) and their generated image(s).

5. Apparatus as claimed in Claim 1, wherein the base frame(s), veffical column(s) and measurement tube(s) may be configured for testing measurement accuracy of computed (axial) tomography (CT) and their generated image(s).

6. Apparatus as claimed in Claim 5, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the computed tomography (CT) reference tool(s). C3

7. Apparatus as claimed in Claim!, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of magnetic resonance imaging (MRI) apparatus and their generated image(s).

10. Apparatus as claimed in Claim 1, wherein the base frame(s), vertical column(s) and measurement tube(s) may be configured for testing measurement accuracy of radio-fluoroscopy (RF) and their generated image(s).

II. Apparatus as claimed in Claim 10, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measurements against that for the radio-fluoroscopy (RF) reference tool(s).

12. Radiological image testing apparatus comprising a base frame(s), measurement devices accessory base, tool supporting block accessory module, and specialised imaging 2-Dimensional, 3-Dimensional and z-axis testing modules, in that the hase flame functions as the first part of a progressive modular imaging system that can be assembled quickly for convenience and made to function as a linear, curved or otherwise defined distance verification tool.

14. Radiological image testing apparatus comprising a base frame(s), vertical column(s), Linear measurement tubes and specialised computed radiography (CR) imaging q4r module(s) for the imaging of 2-Dimensional and 3-Dimensional test objects and reference radio-opaque markers, in that the base frame functions as the first point of a progressive modular imaging system that can be assembled quickly for convenience and made to function as a cross-sectional diameter and linear or otherwise defined distance verification tool(s).

15. Apparatus as claimed in Claim 14, wherein said apparatus and tool configuration(s) can be used to compare manufacturer software measuremenls against that for the computed radiography (CR) imaging tool(s).

16. Apparatus as claimed in Claims i-iS, wherein the tool can be used to verify the measurement accuracies of modality software measurement platforms, and which can be further used to compared image measurement values obtained from images transferred by networking or other image transfer processes to local or remote clinkal review or diagnostic workstation facilities, whose resident software may be similar or dissimilar to manufacturer software on the originating image generation platforms.

The said images may be part of a specific study series of medical images that are transferred by Digital Communications in Medicine (DICOM) version 3 or higher, or other suitable or evolutionary standard, and the tool may be used to assess reconstruction accuracies across different network systems, architectures and software viewing I measuring platforms, such as Picture Archive and Communications System (PACS) systems. These said images may be further assessed against the tool reference values for accuracy, distortion and measurement non-conformancy.

17. Apparatus as claimed in Claims 1-16, wherein said reference values of imaging test tools may be used to test measurement accuracies of software manipulation and measurement packages utilising cross-sectional diameter(s), length (linear or oilier variant), using constructed, reconstructed, multi-planar reconstruction (MPR), Maximum Intensity Projection (MIP), curved reconstruction, other post-processed image manipulation, or other evolutionary software image generated using an alternative principle of construction / reconstruction.

18. Apparatus for generating measurement reference images acquired as a component part of computed tomography (CT) radiological image(s), and which serves to accurately C'5 indicate measurement parameter(s), namely length, diameter, area, volume, pixel, voxel or other preferred unit of image measurement(s).

20. Apparatus as claimed in 18, which may be used as a distance and diameter calibration tool for computerised tomography (CT) measurement programs that may be applied in addition to manufacturer measurement software programs, and which serve to provide a secondary means of measurement venfication based upon the iekence distances and diameters contained in the said apparatus.

21. Apparatus as claimed in 18, where the distance, area, volume or other preferred method of parametric calibration(s) derived from the reference markers contained therein fimction as reference values for a computensed graphical measurement matrix for computensed tomography (CT) that may be applied to and linked to images and image order of the series acquisition, and whereby is used to generate numerical data concerning the linear, area, volume or otherwise, measurement of area(s) of interest for comparison with similarly computer processed measurement(s) obtained by manu1cturer measurement software for the particular radiological imaging modality.

22. A method of assessing accuracy of radiological imaging apparatus, comprising supporting a reference tool, suitable for an imaging technique being used, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tooL

23. Apparatus for generating measurement reference images acquired as a component part of magnetic resonance imaging (MRI) radiological or medical image(s), and which serves to accurately indicate measurement parameter(s), namely length, diameter, area, volume or other preferred unit of image measurement(s).

24. Apparatus as in claim 23, wherein the apparatus may be used to compare measurements obtained from other external magnetic resonance imaging (MIII) measurement methods, and by which comparison of measurement values to that given by the said apparatus will enable the detennination of measurement accuracy matched against that for the said measurement reference(s) built into the apparatus.

25. Apparatus as claimed in 23, which may be used as a distance and diameter calibration tool for magnetic resonance imaging (MRL) measurement programs thai may be applied in addition to manufacturer measurement software programs, and which serve to provide a secondary means of measurement verification based upon the reference distances and diameters contained in the said apparatus.

26. Apparatus as claimed in 23, where the distance, area, volwne or other preferred method of parametric calibration(s) derived from the reference markers contained therein function as reference values for a magnetic resonance imaging (MRJ) graphical measurement matrix that may be applied to and linked to images and image order of the series acquisition, and whereby is used to generate numerical data concerning the linear, area, volume or otherwise, measurement of area(s) of interest for comparison with similarly computer processed measurement(s) obtained by manufacturer measurement software for the particular radiological imaging modality.

27. A method as claimed in Claim 22, of assessing accuracy of computerised tomogiaphic imaging apparatus (CT), comprising supporting a reference tool, suitable for computerised tomographic imaging techniques, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

28. A method as claimed in Claim 22, of assessing accuracy of magnetic resoiwnce imaging apparatus (MRI), comprising supporting a reference tool, suitable for computerised tomographic imaging techniques, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool qR-

31. A method as claimed in Claim 22, of assessing accuracy of computerised radiological imaging apparatus (CR), comprising supporting a reference tool, suitable for computerised radiographic imaging techniques, in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tooL

32. A method as claimed in Claim 22, of assessing accuracy of images transferred across digital image networks by electronic means such as teleradiology, Picture Archive and Communications System (PACS), or other suitable digital image transmission I receiver system, comprising supporting a reference tool, suitable for computcrised radiographic imaging techniques, generation of reference images, in a required position in/on the above mentioned radiological imaging apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool.

33. A method(s) according to Claims 22,27-32, whereby said radiographic imaging apparatus and test tool(s), are subjected to the prescribed methods of testing contained within the stated methods of testing; and other supportive descriptions, for each respective 9c image modality and image viewing / evaluation platform. Derivations or modifications of said method(s) of testing, forms the basis for further testing procedure(s) or methods on the desired imaging modality, and other more complex / preferred testing procedures may be derived by combination(s) of one or more aspects from dissimilar modality test methods and procedures. These testing. methods.may however be subject to change according to - -changes in the-radiographic imaging apparatus, viewing and measuring software, and optimisation of existing test method(s).

34. A method(s) according to Claims 18-21, whereby said measurement accuracy correction tool is used to generate computed tomography (Cl') reference images and measurement ------values-for-diameteriength, area, volume or other parametric quantity, and which will form the basis for comparison with that of the calculated values from manuflicturer measurement software packages.

37. A method(s) according to Claims 23-26, whereby the reference markings, measurement (s) matrix, reference spheres, and reference diameter disks and lines can he used to calibrate or to be used with other computer generated measurement accuracy measurement platforms to validate or compare measurement values derived from manuläcturer software measurement programs against that of the measurement correction accessory module for magnetic resonance imaging (MRI). cc\

*

38. According to a second aspect of the invention, there is provided an electronic and / or computerised version or representation of apparatus in accordance with the first aspect of the invention(s).

39. According to the third aspect of the invention, there is provided apparatus for the measuring of radiological images, substantially as herein described and with reference to and /ot as illustrated in the accompanying drawings.

AMNbMS 1b II CU*4$. 100

Claim 1 A universal imaging phantom for use in quality assurance testing of a broad range of radiological imaging apparatus to perform measurement accuracy verification and correction by use of its modality specific accessory phantom(s) and modality specific measurement corrections phantom(s) to providing image(s) of the selected radiological phantom(s) and by the respective of the imaging modalities and machine apparatus that is to be tested, and which may regarded as a secondary tool function, the components of the universal imaging phantom comprising: a base frame(s) composed of two longitudinal and two transverse sections that are fixed at their end(s) to provide a square, oblong or otherwise shaped construction, and having hole(s) in the c,-.1. nc ii_m,itw inridna nin(& fni the fvM n, derived may give an indication of measurement accuracy, presence of image distortion in the imaging field, and the locality and extent of any measurement inaccuracies, while the z-axis measurement tube(s) will typically not be suited to measurement in a planar section since curvatures will generally traverse in and out of a given orthogonal plane such that ordinary 2-flimensicrnal or nianar measurement tools would not be able to provide an accurate O3 measurement rod with radio-opaque scalar markings indicating typically 5 millimetres and 10 millimetres along its length that produce the reference value(s) of diameter and length in the image(s) or volumetric image dataset, and where the spatial relationship(s) of said accessory phantom produces typical reference(s) of length and separation of the lines in a given inni, wlug. k ni h iicM fr pvi1iiitp 1nnoihidini1 trnwere nd denth 1ot the images of the x-axis and y-axis linear measurement tools and a planar length measurement may be performed along the length of the wire or the length of the radio-opaque fluid column within the measuring tube, and comparison of the value(s) of diameter of the central wire of the measurement tube, the width of the measurement tube, the length of the central wire or the fling1,.Miimn nv he iimnirei1 iaint the reference vi1iw1s' gnntnined internally and images, and the z-axis measurement tube is recorded in an extensive number of axial, sagittal and coronal images such that the length measurement tools of the scanner can be applied to the images of the x-axis and y-axis linear measurement tools and a planar length measurement may be performed along the length of the wire or the length of the radio-opaque fluid column ti+k.r,k. iimrnn ti,hp ntl tan nirin nfth vdiiWg' nfdi2meter nf the central wire of the length of the measurement tube, such that measurement value(s) derived may give an indication of measurement accuracy, presence of image distortion in the imaging field, and the locality and extent of any measurement inaccuracies, while the z-axis measurement tube(s) will typically not be suited to this type of measurement in a planar image since its curvatures will nImprQllu tvuprc in ing4 nit nfc. aiuen nrthnonnsil ninne such that nlanar measurement may be produced on the scintillation crystal of the gamma camera, and where the markers on the external faces of the measurement scales typically run from negative multiples of 40 millimetres at one end, for example -160 millimetres, -120 millimetres, -80 millimetres, -40 millimetres to zero at the centre of the tool, then to a positive multiple of 40 millimetres at the ttbpr nd fnr examnie 40 millimetres.. gp millimetres. 120 millimetres and 160 millimetres, 1o secured into position using locking pins, and correspondingly where x-axis and y-axis measurement tubes are attached to the face(s) of the phantom support column(s) and a singularity or plurality of z-axis measurement tubes engaged and fastened into the octagonal socket(s) of the said support column, such that when placed into each imaging machine in f the said universal oc1 image information, compressing the data, transmitting the data, and reconstructing the data and presenting it on an image display, and where the modality specific accessory unit for computed radiography (CR) consists of an imaging section constructed from perspex (RTM), acrylic or other suitably non-magnetic, radiolucent, durable and transparent material and p,r,,nn 1w vomrJ rrilv n gthlnna h1n'k nftvnit'1 dimensinns 6O millimetres 1enth by tto a modality specific phantom for measurement accuracy verification of diameter(s), area(s), volume(s) and distance(s) measurements of image(s) generated by computed and digital radiography apparatus (CR), and transferred by network technologies to picture archive and communications systems (PACS) and teleradiology systems using digital imaging and in m ,lu.inp (flI('flLfl r rithr t'rpntpA ime transfer standard. and which

U I

a modality specific measurement accuracy correction phantom for computed tomography (CT) is used to generate a 1 centimetre cubical reference matrix as a component in an image and below the subject or phantom being imaged such, that the image of the said matrix is integrated with image(s) of the universal imaging phantom configured for computed tnmnminhv (CT' and containing the oreferred modality specific accessory phantom(s) that function from 1 centimetre cubes or from multiples thereof in any direction and any reference made to geometrical relationships are purely in the interests of quick calculation of length, and by way of example only, a 3 centimetre line of reference drawn across four spheres and a 4 centimetre line drawn across five spheres will have a line that joins them that passes through six of the spheres obliquely and will have a length of five centimetres; and a modality specific measurement accuracy correction phantom for magnetic resonance imaging (MRI) is used to generate a 15 millimetre cubical reference matrix as a component in an image and below the subject or phantom being imaged, such that the image of the said matrix is integrated with image(s) of the universal imaging phantom configured for magnetic resonance imaging (MRI) and containing the preferred modality specific accessory phantom(s) that may be accessed if required by dropping the viewing plane to a point below that of the said modality specific accessory phantom for magnetic resonance imaging (MRI), such that the said measurement accuracy correction phantom is designed to work in conjunction with the base frame and secured phantom support column(s), x-axis and y-axis linear measurement tube(s) attached to the faces of the said phantom support column(s) by clip extensions and z-axis measurement tube(s) mounted and secured into the octagonal or otherwise shaped sockets of the phantom support column, and water or other fluid tank enclosure if preferred, and by way of example only, the measurement accuracy correction phantom is integrated into the imaging table of the magnetic resonance imaging (MRI) apparatus, and where the construction of the said measurement accuracy correction phantom is made from perspex (RTM), acrylic or other radiolucent and non-magnetic material frame and shaped by way of example only into an oblong shape, and where the said measurement accuracy correction phantom comprises a number of not less than two, and typically not more than five planar single sections, in order that the added inertia to the table is minimised, and that table indexing and movement are not altered, and each complete sectional layer is typically of a thickness that a 5 millimetre or otherwise diameter sphere of oil or other magnetic resonance signal generating fluid is embedded into the middle of the two sections and in an indentation on each upper and lower surface at a plurality of appropriately positioned and linearly related loci across the surface of the material to form lines of reference on the said section(s), and where the separation of these oil spheres is typically 15 millimetres longitudinally and transversely from each of their respective centres so as to form a 15 millimetre cubical matrix covering the larger aspect of * the upper surface of the section, and where by way of example only, the oil spheres are arranged such that the first and last sphere is 5 millimetres diameter with a spatial separation of 15 millimetres longitudinally and a transverse width separation of 15 millimetres across the whole of the said measurement accuracy correction phantom in that specified layer and all other layers forming the construction forming the correction matrix, and such that following * imaging, access to image(s) of the measurement correction phantom is similar to that for the CT measurement accuracy correction phantom and the 15 millimetre matrix may be accessed by dropping the plane of viewing below the subject being measured, where lines drawn between the centre points of each oil capsule longitudinally, transversely and vertically will * give measurement accuracy reference comparison against value(s) derived from imaging modality measurement tools in orthogonal planes, whilst oblique measurements may be calculated by the application of geometrical relationships as applied to the CT measurement accuracy correction phantom, although it has to be appreciated that there are no lines or triangles used in the construction of the correction matrix and reference to them is purely by way of illustration only. 1v7

Claim 2 Apparatus as claimed in Claim 1, wherein the universal imaging phantom in a non-configured form consists of a base frame for receiving phantom support column(s) which may be engaged and locked into place by locking pins in a singularity or a plurality, or an accessory phantom base plate may be engaged into the base frame and secured in by the said locking pins, or a combination of a singularity or a plurality of phantom support column(s) and an accessory phantom base plate may be selected for the attachment of and securing by means of locking pins, a range of attachments called modality specific accessory phantoms which are test phantoms designed to be imaged by a specific type of imaging process or imaging modality, and the image(s) generated will be dependent on the type of imaging technology used and the physical principle used to create the image(s), the optimised and time based method(s) of recording changes or collecting data within the dynamic processes of the image formation such that the image(s) generated will contain detailed information relating to the internal and external features of design and construction of the selected phantom, and the universal imaging phantom being the first functional component of all of the configurations of the universal imaging phantom, regardless of the number(s) and type(s) of modality specific accessory phantom(s) comprising it.

Claim 3 Apparatus as claimed in Claim 1, wherein the universal imaging phantom is configured for measurement accuracy verification of computed tomography (CT) and its configuration comprises base frame, a singularity of phantom support column(s), x-axis and y-axis linear measurement tube(s) and a singularity or plurality of z-axis measurement tubes engaged and fastened into the octagonal socket(s) of the said support column(s), and locking pins for securing the phantom support column(s) to the base frame, such that when the universal imaging phantom for computed tomography (CT) is imaged it generates 2-Dimensional images (or planar or linear image(s) in discrete sectional thicknesses that may only be viewed on a display that only represents two dimensions of information at a time, namely x-axis and y-axis image data with little discernable appreciation of z-axis data or depth of image), or volumetric or 3-Dimensional images (planar and linear images recorded as a block of image data which may be dynamically viewed as a scrolling image that freely passes through the image block allowing viewing of the subject in any orientation, and may be viewed on a display where the image data can be freely re-orientated and at variable thickness of image), and where the computed tomography ***** configuration of the said universal imaging phantom generates images ofthe modality specific accessory phantom in a required position in the apparatus; forming an image(s), or series of *.* images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of : * the tool, and such that the said accessory phantom for computed tomography may be used to * provide an image(s) or series of images that may be viewed using the volumetric imaging display platforms of multi-planar reconstructions (MPR's), maximum intensity projections (MIP's) and curved reconstructions, which are developed to enable non-linear structures to be viewed in :. totality and to be re-orientated in space to enable the image measurement tools to be able to effectively trace the outline of the structure and to record accurate measurements of diameter, * * area, volume and length, such that the value(s) of said parametric measurements may be compared against the measurement reference value(s) of the said accessory phantom thus evaluating the measurement accuracy of image measuring tools of the computed tomography scanner.

Claim 4 Apparatus as claimed in Claim 1, wherein the universal imaging phantom is configured for measurement accuracy verification of computed tomography (CT) and its configuration comprises a base frame with accessory phantom base plate secured by locking pins, and a u4-modality specific accessory phantom for computed tomography (CT) slotted into the accessory phantom base plate such that when the universal imaging phantom for computed tomography (CT) is imaged it generates 2-Dimensional images (or planar or linear image(s) in discrete sectional thicknesses that may only be viewed on a display that only represents two dimensions t fimp nimph, ntl y..yjc ime iist with little discernable anoreciation imaging phantom generates images of the modality specific accessory phantom in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool, and such that the i,1 t-r.pqqnrv nhntnm fnr tnmniitd tnmnorinhv m'iv he aiseil fri nrnvide an imae(s' nr series Wa said accessory phantom thus evaluating the measurement accuracy of image measuring tools of the magnetic resonance imaging scanner.

Claim 7 Apparatus as claimed in Claim 1, wherein the universal imaging phantom is configured for measurement accuracy verification of digital subtraction angiography (DSA) and radio-f1nnrn'iiiw (RP\ sind its tnnfimimtian enmnrises base frame. ohantom SUPPOII column(s), x-axis tn imaging (NI) configurations of the said universal imaging phantom generates image(s) of the modality specific accessory phantoms for both in turn in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained -. ..e1. + ,.. ,c.i +h+ fh i.I rpcnrv nhntnm fnr that have good accuracy of positioning and spatial separation in all three orthogonal imaging planes.

Claim 10 Apparatus as claimed in Claim 1, wherein the universal imaging phantom is configured for measurement accuracy verification of computed radiography (CR) and its configuration comprises base frame, modality specific accessory phantom for computer radiography (CR) and -. --.t__ --_L,....s.. 4 41...,.

reader of known performance, and additionally where image(s) of the said x-axis and y-axis linear measurement tube(s) indicate peripheral image distortion of the image(s) and the level of magnification at a given height above the imaging plate of the computed radiography (CR) imaging system, and the z-axis measurement tubes may give an assessment of distortion of shape -- - .i.,1,L iitinn nf tliQthnte between the radio-onaoue

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when obtained and plotted on a graph would give a linear relationship of contrast mdcx against the square reference number, and where such testing may be carried out using an added filter equivalent to 1 millimetre of copper to harden the X-radiation beam and absorb lower energy wavelength radiation that may reduce the image contrast levels in the image(s) generated, using a *,+ . *j iJtp ab tnf\ tn rpi4nt'p t2 unthreaded nylon or other suitable non-magnetic material headed locking pin may then be placed into each of the two holes to allow the base plate accessory module to be fixedly or releasably and I or variably secured together with the base frame, and where said frame has a number of retaining clips for holding specified diameter linear measuring tube(s) in longitudinal, transverse i., ,1f ymriip nnlv th lvnical diameter(s for the transverse (2,1 thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool, and such that the said accessory phantom for computed tomography may be used to provide an image(s) or series of images that may be viewed using the volumetric imaging display platforms of multi-planar reconstructions (MPR's), maximum (M1P' rnd mwvM rennstructinns.. which are develoned to enable non-ends of the sectional construction is a section containing a range of disks of increasing diameter and depth whose function is to give length reference to the electronic cursor measurements of known diameter planar disks of 25, 20, 15, 10, 2 millimetres diameter, and functions to provide a selection of reference diameter(s) to test the image measurement tools for their abilities to Aipr(\ ne iii ffprimrif ewthnannil nknv ini1 giwh thpt the imads' of the and to record accurate measurements of diameter, area, volume and length, such that the value(s) of said parametric measurements may be compared against the measurement reference value(s) of the said accessory phantom thus evaluating the measurement accuracy of image measuring tools of the computed tomography scanner, but equally where in the normal imaging and mc,i,rinn gn Mitinnil a't nf reference value(s' may be accessed and which may be Claim 15 Apparatus as claimed in Claim 1, wherein the universal imaging phantom may be selectively configured for the modality specific testing of a wide range of radiological imaging machines and the image(s) generated of the said modality specific accessory phantom or modality specific measuring accuracy correction phantom in a required position in the apparatus; forming an image(s), or series of images of the reference tool and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool, may be applied to all situations involving the measurement accuracy of image measuring tools found on 2-Dimensional or planar image viewing displays which are only capable of presenting an image(s) that contain x-axis and y-axis image data and very little z-axis image data such that the image lacks any real depth of image and image(s) exist as discreet sections of defined length and width but with no real thickness, and where more particularly the image(s) produced by the universal imaging phantom is specifically designed to enable evaluation of measurement accuracy of image measuring tools found on image displays of computerised tomography (CT) and magnetic resonance imaging (MRI) scanners where the image(s) generated are 3-Dimensional or volumetric images which are designed to display image data in x-axis, y-axis and z-axis, such that the image may be viewed in any viewing plane or image orientation and the image may be readily scrolled through in discreet sections of a defined thickness, and which can be reconstructed in any orientation and in any preferred thickness, and such that imaging of the modality specific accessory phantom or modality specific measuring accuracy correction phantom in a required position in the apparatus; forming an image(s), or series of images of the reference tool(s) and obtaining at least one measurement thereof from the image; and comparing the at least one measurement thus obtained with at least one known measurement of the tool, and where that the evaluation of the image(s) generate value(s) that may be compared to the known references in the modality specific accessory phantom or the modality specific measurement accuracy correction phantom thus evaluating the measurement accuracy of image measuring tools of the respective radiological imaging machine and the respective configuration of the universal imaging phantom. * ** *. S * S. U,.. * I * U. U. S U.. *

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