WO2006090321A1 - Determination of the coverage of a ct scan - Google Patents
Determination of the coverage of a ct scan Download PDFInfo
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- WO2006090321A1 WO2006090321A1 PCT/IB2006/050542 IB2006050542W WO2006090321A1 WO 2006090321 A1 WO2006090321 A1 WO 2006090321A1 IB 2006050542 W IB2006050542 W IB 2006050542W WO 2006090321 A1 WO2006090321 A1 WO 2006090321A1
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- A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
- A61B6/03—Computerised tomographs
- A61B6/032—Transmission computed tomography [CT]
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/46—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with special arrangements for interfacing with the operator or the patient
- A61B6/467—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with special arrangements for interfacing with the operator or the patient characterised by special input means
- A61B6/469—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with special arrangements for interfacing with the operator or the patient characterised by special input means for selecting a region of interest [ROI]
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Abstract
A control unit (118) for a computer tomography apparatus (100) for examination of an object of interest (107) is adapted to control the computer tomography- apparatus (100) to detect, by detection elements (123) rotating around the object of interest (107) , first electromagnetic radiation signals emitted by an electromagnetic radiation source (104) rotating around the object of interest (107) and passed through a first portion (404) of the object of interest (107) , determine, based on the detected first electromagnetic radiation signals, first structural information concerning 'the first portion (404) of the object of interest (107) , determine, based on the first structural information, a second portion (450) of the object of interest (107) as a region of interest, detect, by the detection elements (123) rotating around the object of interest (107) , second electromagnetic radiation signals emitted by the electromagnetic radiation source (104) rotating around the object of interest (107) and passed through the second portion (450) of the object of interest (107) , determine, based on the second electromagnetic radiation signals, three-dimensional structural information as second structural information concerning the second portion (450) of the object of interest (107) , and display the three-dimensional structural information.
Description
DETERMINATION OF THE COVERAGE OF A CT SCAN
The invention relates to the field of X-ray imaging. In particular, the invention relates to a control unit for a computer tomography apparatus, to a computer tomography apparatus, to a method of examining an object of interest with a computer tomography apparatus, to a computer-readable medium and to a program element. Computed tomography (CT) is a process of using digital processing to generate a three-dimensional image of the internals of an object (for instance a human body) from a series of two-dimensional X-ray images taken around a single axis of rotation. The reconstruction of CT images can be done by applying appropriate algorithms. According to the prior art, the coverage of a CT scan is defined by a radiologist based on a so-called pilot-scan. A pilot-scan (also denoted as a CT scout view or scannogram or topogram) produces a flat image like a plane radiograph to produce this image, the X-ray tube does not rotate while the patient is moved through the scanner. This form of imaging can also be used as a means for obtaining planar images.
In other words, during the pilot-scan, the gantry of the computer tomography apparatus does not rotate and the array of X-ray source and X-ray detector is shifted along a length of an object of interest under investigation. Then, the radiologist identifies an organ of interest from the two-dimensional picture scanned during the pilot- scan, and determines manually in which region the actual scan will be carried out. However, the organ of interest is in many cases difficult to recognize in a pilot-scan image, which causes the radiologist in many cases to use a rather large coverage in order to ensure that the organ of interest is covered by the scan. This implies that more dose is applied to the patient than required, and the scan takes longer than necessary.
US 6,480,561 B 2 discloses a method of forming a scannogram for a CT apparatus. During the acquisition of the measured values for the scannogram, the scanning unit or the radiation source rotates about the examination zone and a data set is reconstructed from the measured values acquired during the acquisition, based on an attenuation analysis. A synthetic projection image can be calculated as the scannogram from the data set.
There is a need for a system allowing to localize a region of interest for a subsequent computed tomography scan with low radiation dose and low effort, and to display reconstructed information in a clear manner.
This may be achieved by a control unit for a computer tomography apparatus, by a computer tomography apparatus, by a method of examining an object of interest with a computer tomography apparatus, by a computer-readable medium and by a program element with the features according to the independent claims.
According to an exemplary embodiment of the invention, a control unit for a computer tomography apparatus for examination of an object of interest is provided, wherein the control unit is adapted to control the computer tomography apparatus to detect, by detection elements rotating around the object of interest, first electromagnetic radiation signals emitted by an electromagnetic radiation source rotating around the object of interest and scattered from or passed through a first portion of the object of interest, determine, based on the detected first electromagnetic radiation signals, first structural information concerning the first portion of the object of interest, and determining, based on the first structural information, a second portion of the object of interest as a region of interest. Further, it is detected by the detection elements rotating around the object of interest, second electromagnetic radiation signals emitted by the electromagnetic radiation source rotating around the object of interest and passed through the second portion of the object of interest. The control unit is further adapted to control the computer tomography apparatus to determine, based on the second electromagnetic radiation signals, three-dimensional structural information as second structural information concerning the second portion of the object of interest. Further, the three-dimensional structural information may be displayed.
According to another exemplary embodiment of the invention, a computer tomography apparatus for examining an object of interest is provided, comprising an electromagnetic radiation source adapted to emit electromagnetic radiation to the object of interest and adapted to rotate around the object of interest, detecting elements adapted to detect electromagnetic radiation emitted by the electromagnetic radiation source and passed through the object of interest and adapted to rotate around the object of interest, and a control unit having the above-mentioned features.
According to yet another exemplary embodiment of the invention, a method of examining an object of interest with a computer tomography apparatus is provided, comprising the steps of detecting, by detection elements rotating around the object of interest, first electromagnetic radiation signals passed through a first portion of the object of interest, determining, based on the detected first electromagnetic radiation signals, first structural information concerning the first portion of the object of interest, and determining, based on the first structural information, a second portion of the object of interest as a region of interest. Further, it is detected, by the detection elements rotating around the object of interest, second electromagnetic radiation signals passed through the second portion of the object of interest. Moreover, it is determined, based on the second electromagnetic radiation signals, three-dimensional structural information as second structural information concerning the second portion of the object of interest. Further, the three-dimensional structural information is displayed.
Beyond this, according to another exemplary embodiment of the invention, a computer-readable medium is provided, in which a computer program of examining an object of interest is stored which, when being executed by a processor, is adapted to carry out the above-mentioned method steps.
Moreover, according to a further exemplary embodiment of the invention, a program element of examining an object of interest is provided, which, when being executed by a processor, is adapted to carry out the above-mentioned method steps. The examination of an object of interest according to the invention can be realized by a computer program, i.e. by software, or by using one or more special electronic optimization circuits, i.e. in hardware, or in hybrid form, i.e. by means of
software components and hardware components. The computer-readable medium and the program element may be implemented in a control system for controlling a computer tomography apparatus.
The characterizing features according to the invention particularly have the advantage that the conventional pilot-scan for determining a region of interest of an object of interest which region shall be subject of a subsequent detailed CT investigation, it is substituted by a low-quality CT investigation preceding the actual or main CT investigation. In other words, a circular or helical CT scan as carried out conventionally during the actual determination of the three-dimensional structure of a region of interest is carried out instead of a pilot-scan according to the invention, preferably with a decreased radiation dose, and a noisy low resolution reconstruction of the volume under investigation can be used to plan the actual subsequent CT measurement. The low resolution reconstruction, however, allows to determine a region inside of an object of interest which shall be investigated by a CT main scan in more detail, for instance a part of the human body (e.g. an organ).
After having obtained the three-dimensional structural information of the limited portion of the object under investigation, this three-dimensional structural information may be displayed on a display device. Such a display device may be a monitor on the basis of a cathode ray tube (CRT), a liquid crystal display (LCD) or a plasma display device. The presentation of the reconstructed image of the region of interest in a 3D manner allows a very detailed and meaningful analysis or diagnosis of the "zoomed" portion of the object under examination and allows to view the region of interest in different orientations.
Instead of acquiring a two-dimensional planar transmission image of the object of interest (as done during a conventional pilot-scan), the invention acquires data for a low resolution three-dimensional image as a basis for the determination which part of an object of interest shall be investigated in more detail as a region of interest. This allows to define a region of interest within the object of interest which is subsequently irradiated with a higher radiation dose with increased accuracy. Since the region of interest can be localized in an improved manner according to the invention, the volume to be irradiated with the higher radiation dose can be significantly reduced, thus reducing the entire radiation dose needed.
According to one aspect of the invention, a conventional pilot-scan with a fixed geometry is replaced by a three-dimensional helical or circular scan with reduced dose compared to the actual subsequent measurement. Then, a noisy three- dimensional image can be used for planning the actual scan, wherein the noisy three- dimensional image is reconstructible based on an auxiliary or preceding scan.
A region to be conventionally covered by a pilot- scan may be scanned, according to the invention, using a low dose helical scan. For instance, approximately the same dose (mAs) may be used for this scan as for the traditional pilot-scan. Subsequently, a noisy, low resolution volume may be reconstructed from the data acquired during the low dose helical scan. Then, the organ of interest may be segmented in this volume, e.g. by model based segmentation, and the region of interest for the diagnostic scan may be determined based on the detected position inside of the organ. Optionally, a radiologist may subsequently check the result of the segmentation and may adjust the obtained region of interest, if desired or necessary. Then, the diagnostic scan may be performed based on the outcome of the previous steps.
An advantage of the procedure according to an exemplary embodiment of the invention is that a segmentation based on shape models can cope with a (for instance slightly) truncated object. So even if the helical pilot-scan was too short to cover the region of interest completely, the procedure can still provide the correct region of interest to be covered by the diagnostic scan. Additionally, dose sensitive organs can be segmented and the scan parameters like gantry tilt can be chosen automatically such that these organs get as little dose as possible.
In the following, exemplary embodiments of the invention will be described in more detail. Next, exemplary embodiments of the control unit will be described.
However, these embodiments apply also for the computer tomography apparatus, for the method of examining an object of interest with a computer tomography apparatus, for the computer-readable medium and for the program element.
The control unit may be adapted to control the computer tomography apparatus in such a manner that the first portion includes the second portion or overlaps the second portion. In other words, the first portion should generally be larger than the second portion. In other words, the region under investigation is limited by the auxiliary
scan preceding the main scan. However, even when the region of interest is located in a border area of the first portion (for instance only a part of a bladder is visible in the first image), then, based on the knowledge of the expected shape of the region of interest (a typical shape of a human bladder) can be used to determine an appropriate coverage of the subsequent main scan.
The control unit may be adapted to control the computer tomography apparatus in such a manner that a resolution of the first structural information is lower than a resolution of the second structural information. A relatively small resolution is sufficient for the determination of the region of interest, which resolution is in many cases worse than the final resolution of the second scan. By taking this measure, the radiation dose to which the object of interest is exposed during the pre-scan, can be significantly reduced.
The control unit may be adapted to control the computer tomography apparatus in such a manner that a radiation dose emitted by the electromagnetic radiation source for detecting the first electromagnetic radiation signals is lower than a radiation dose emitted by the electromagnetic radiation source for detecting the second electromagnetic radiation signals. A relatively poor resolution of the preliminary scan is sufficient for the determination of the region of interest, and simultaneously the amount of radiation absorbed by the object of interest is reduced. Further, the control unit may be adapted to control the computer tomography apparatus in such a manner that, for detecting the first electromagnetic radiation signals and the second electromagnetic radiation signals, the electromagnetic radiation source and the detection elements may rotate around the object of interest along a circular or a helical trajectory. In other words, for both the first and the second scans, a helical or circular scan may be carried out, that is the electromagnetic radiation source and the detection elements may be arranged on a gantry to rotate around the object under investigation. A circular scan is particularly advantageous when a multi- slice detector is used and the region of interest fits into the cone completely. In the case of a helical scan, a single- slice detector or a multi- slice detector may be used. The control unit may be adapted to control the computer tomography apparatus in such a manner that determining the region of interest is performed based on a user-defined information provided via a user interface. In other words, a user may
define, based on a reconstructed noisy three-dimensional image of the object under investigation, in which part of the object under investigation the region of interest shall be located which is scanned subsequently with higher intensity. For instance, an expert in the field of investigating human patients can introduce his background knowledge concerning typical organs of a human being under investigation so that, via the interface, human experience, intelligence or knowledge may be introduced in a system as a basis for a semi- automated determination of the region of interest.
Additionally or alternatively, the control unit may be adapted to control the computer tomography apparatus in such a manner that determining the region of interest is performed based on a pre-stored database information. In such a database, typical shapes or other information related to the expected region of interest can be stored (for instance typical sizes or shapes of human organs) so that an automatic mapping can be carried out using image processing schemes in order to automatically locate a region of interest within the object of interest for a further examination. The control unit may, additionally or alternatively, be adapted to control the computer tomography apparatus in such a manner that determining the region of interest is performed using a model-based segmentation. In other words, a model for an expected region of interest may be introduced in the system so that the system detects the object of interest automatically to properly determine the region of interest. The control unit may be adapted to control the computer tomography apparatus in such a manner that a three-dimensional structure of the first portion is determined as the first structural information. In other words, also the determination of the structure of the first portion may include determining steric information, so that a three-dimensional image of the first portion of the object may be reconstructed as a basis for planning the actual CT main scan. This refines the method of determining a region subjected to radiation for the main scan.
The control unit may further comprise a user-interface which is adapted to enable a user to check and/or modify the determined region of interest. In a scenario, in which a control unit has detected (semi-) automatically a region of interest, it may happen in a worst case scenario, that the region of interest is determined in a non- optimum or even in an erroneous manner. In this case, a human user may intervene and may modify the determined region of interest, if preferred or desired or necessary.
Furthermore, the control unit may be adapted to control the computer tomography apparatus in such a manner that a radiation dose emitted by the electromagnetic radiation source for detecting the second electromagnetic radiation signals is adjusted in accordance with pre- stored information concerning the region of interest. Such information may be biological or physiological information or may geometrical or shape or material information. For instance, human organs under investigation which are very sensitive with respect to ionizing radiation may be retrieved, and it may be decided that the radiation dose to which these organs are exposed, are reduced to comply with biological or physiological frame conditions. According to the invention, the control unit may be adapted to control the computer tomography apparatus in such a manner that determining the region of interest may be performed in a manual manner, in a semi-automatic manner or in a fully- automatic manner. An automatization of the recognition of a region of interest (for instance under application of methods like image processing schemes, object recognition methods, model-based segmentation of an image supported by a database, if desired) within an image of a portion of an object under examination increases the accuracy of limiting a range for a subsequent CT main scan, thus reducing the radiation exposure. Further, taking this measure allows to significantly decrease the time for determining which part of the object of interest shall be scanned in more detail, which reduces the examination time of the object of interest. Moreover, even an experienced person may have problems to recognize particular portions in an image having a weak contrast (like the bladder of a human being), wherein an image analysis unit may be able to clearly distinguish such a portion from the environment. However, it is also possible that a user defines the second portion manually. "Semi-automated" determination includes taking into account information provided by a user for the reconstruction of a region of interest (for instance an organ within a human body). For instance, a person may roughly limit a part of the first portion of the object of interest in which the person expects the region of interest. The system of the invention then determines the second portion only within the limits defined by the person. Thus, semi-automated determination combines the complementary skills of a machine and of a human user.
Next, exemplary embodiments of the computer tomography apparatus
will be described. However, these embodiments also apply for the control unit, for the method of examining an object of interest with the computer tomography apparatus, for the computer-readable medium and for the program element.
The computer tomography apparatus may comprise a collimator arranged between the electromagnetic radiation source and the detecting elements, wherein the collimator may be adapted to collimate an electromagnetic radiation beam emitted by the electromagnetic radiation source to form a fan-beam or a cone -beam. Such a collimator allows to define the radiation profile.
The detecting elements may form a single-slice detector array. This configuration allows to construct a computer tomography apparatus with low effort.
Alternatively, the detecting elements may form a multi- slice detector. This configuration can be advantageously combined with a circular scan, if the region of interest fits into the cone completely. However, even a helical scan be combined with a multi-slice detector array to carry out the examination in a short fast time. The computer tomography apparatus according to the invention may be configured as one of the group consisting of a medical application apparatus, a material testing apparatus and a material science analysis apparatus. The invention creates a high quality automatic system that can automatically recognize certain types of material. Such a system may have employed the computer tomography apparatus of the invention with an X-ray radiation source for emitting X-rays which are transmitted through or passed through the examined person to a detector allowing to detect a region of interest within the object of interest in a high accuracy manner.
The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.
The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.
Fig. 1 shows a computer tomography apparatus according to an exemplary embodiment of the invention,
Fig. 2 shows a flow-chart according to a method of examining an object of interest according to an exemplary embodiment of the invention,
Fig. 3A to Fig. 3C illustrate the functionality of one aspect of the invention,
Fig. 4A and Fig. 4B show schematic views of a computer tomography apparatus during a method of examining an object of interest according to an exemplary embodiment of the invention, Fig. 5 shows an exemplary embodiment of a data processing device to be implemented in the computer tomography apparatus according to an exemplary embodiment of the invention.
The illustration in the drawings is schematically. In different drawings, similar or identical elements are provided with the same reference signs.
Fig. 1 shows an exemplary embodiment of a computed tomography scanner system according to the present invention. With reference to this exemplary embodiment, the present invention will be described for the application in examination of an organ of a human patient. However, it should be noted that the present invention is not limited to this application, but may also be applied in other fields of medical imaging, or other industrial applications such as material testing. The computer tomography apparatus 100 depicted in Fig. 1 is a cone- beam CT scanner. However, the invention may also be carried out with a fan-beam geometry. The CT scanner depicted in Fig. 1 comprises a gantry 101, which is rotatable around a rotational axis 102. The gantry 101 is driven by means of a motor 103. Reference numeral 104 designates a source of radiation such as an X-ray source, which, according to an aspect of the present invention, emits a polychromatic radiation.
Reference numeral 105 designates an aperture system which forms the radiation beam emitted from the radiation source to a cone-shaped radiation beam 106.
The cone-beam 106 is directed such that it penetrates an object of interest 107 arranged in the center of the gantry 101, i.e. in an examination region of the CT scanner, and impinges onto the detector 108. As may be taken from Fig. 1, the detector 108 is arranged on the gantry 101 opposite to the source of radiation 104, such that the surface of the detector 108 is covered by the cone beam 106. The detector 108 depicted in Fig. 1 comprises a plurality of detector elements 123 each capable of detecting X-rays which have passed through the object of interest 107.
During scanning the object of interest 107, the source of radiation 104, the aperture system 105 and the detector 108 are rotated along the gantry 101 in the direction indicated by an arrow 116. For rotation of the gantry 101 with the source of radiation 104, the aperture system 105 and the detector 108, the motor 103 is connected to a motor control unit 117, which is connected to a control unit 118 (which might also be denoted as a calculation or determination unit).
In Fig. 1, the object of interest 107 is a human patient which is disposed on a mounting table 119. During the scan of the object of interest 107, while the gantry 101 rotates around the item of human patient 107, the mounting table 119 displaces the object of interest 107 along a direction parallel to the rotational axis 102 of the gantry 101. By this, the object of interest 107 is scanned along a helical scan path. The mounting table 119 may also be stopped during the scans to thereby measure signal slices. However, it should be noted that in all of the described cases it is also possible to perform a circular scan, where there is no displacement in a direction parallel to the rotational axis 102, but only the rotation of the gantry 101 around the rotational axis 102.
Further, it shall be emphasized that, as an alternative to the cone -beam configuration shown in Fig. 1, the invention can be realized by a fan-beam configuration. In order to generate a primary fan-beam, the aperture system 105 can be configured as a slit collimator.
The detector 108 is connected to the control unit 118. The control unit 118 receives the detection result, i.e. the read-outs from the detector elements 123 of the detector 108 and determines a scanning result on the basis of these read-outs. Furthermore, the control unit 118 communicates with the motor control unit 117 in order to coordinate the movement of the gantry 101 with motors 103 and 120 with the mounting table 119 and communicates with the X-ray source 104 to control radiation
dose and exposure time.
The control unit 118 may be adapted for reconstructing an image from read-outs of the detector 108. A reconstructed image generated by the control unit 118 may be output to a display 130 via an interface 122. The control unit 118 may be realized by a data processor to process readouts from the detector elements 123 of the detector 108.
The computer tomography apparatus 100 comprises the X-ray source 104 adapted to emit X-rays to the object of interest 107. The collimator 105 provided between the electromagnetic radiation source 104 and the detecting elements 123 is adapted to collimate an electromagnetic radiation beam emitted from the electromagnetic radiation source 104 to form a cone-beam. Alternatively, not shown in Fig. 1, a slit collimator can be used instead of collimator 105 to produce a fan-beam. The detecting elements 123 form a multi- slice detector array 108. The computer tomography apparatus 100 is configured as a medical examination apparatus. The control unit 118 for the computer tomography apparatus 100 for examination of the object of interest 107 is adapted to control the computer tomography apparatus 100. In the frame of this control, it is detected by the detection elements 123 rotating around the object 107 whilst being fixed to the rotating gantry 101, first electromagnetic radiation signals emitted by the X-ray source 104 rotating around the object of interest 107 and passed through a first portion of the object of interest 107. In this step, a relatively large portion (namely the so-called first portion) of the object of interest 107 is irradiated with radiation of a relatively low radiation dose, wherein the first portion is such a portion of the object of interest 107 in which an organ of the human being 107 to be examined is expected. Next, based on the detected first electromagnetic radiation signals, which are detected by the detection elements 123, low resolution structural information concerning the first portion of the object of interest 107 is determined by the control unit 118. In other words, a noisy low- resolution three-dimensional image of the first portion is reconstructed. Based on this determined first structural information, a second - more limited - portion of the object of interest 107 is defined as a region of interest. For this purpose, the first portion is analyzed by an image mapping procedure, that is shapes of this content is compared to typical shapes of the organ to be investigated (for instance a human bladder) which
typical shapes are stored in a database. If a portion is identified to possibly equal to a typical shape of a bladder, a region of interest is defined in an environment of such a portion.
Subsequently, the detection elements 123 again rotate around the object of interest 107 and detect second electromagnetic radiation signals emitted by the X-ray source 104 rotating around the object of interest and passed through the second - limited - portion of the object of interest 107. This irradiation and detection step is carried out with an increased radiation dose, since now it is desired to take a scan of the bladder-shaped portion within the object of interest 107 in more detail. Based on the second refined electromagnetic radiation signals, it is determined structural information concerning the second portion of the object of interest 107.
Additionally or alternatively, user defined information may be provided by a user interface for determining the region of interest. For instance, a physician can detect from his experience from the first noisy CT image that a portion within the object of interest 107 is probably a bladder. Using this human experience, the physician or radiologist may introduce this information via a user interface and may define the region of interest semi- automatically/manually which is subsequently scanned in more detail. When the three-dimensional image of the bladder is reconstructed, this 3D image can be displayed on the display device 130, which is a graphical user interface (GUI) and allows a user to observe the bladder in one or more desired orientations.
In the following, referring to Fig. 2, a flow-chart 200 will be described illustrating an exemplary embodiment of the method for examining an object of interest with a computer tomography apparatus.
In a step 210, the procedure starts. In a step 220, a low-dose helical scan is performed on a large area of an object of interest. In a subsequent step 230, a low resolution 3D volume is reconstructed based on the data captured during the low dose helical scan of step 220. Although this reconstructed volume is relatively noisy, its resolution is sufficient such that in a step 240, a region of interest may be segmented by model-based segmentation. Optionally, a human user may interfere in the procedure 200 by checking or modifying the segmented region of interest in a step 250, whereas this segmented region of interest is subject of a high-dose helical scan performed in step 260. This helical scan is carried out on a locally reduced volume so that the high-dose is
only impinged on a small portion of the object. Based on the detection data captured during step 260, it is reconstructed, in a step 270, a high resolution image of the region of interest defined in step 240 or 250. In step 280, the method ends.
In the following, referring to Fig. 3A to Fig. 3C, a principle of the invention will be described based on a simulation.
Fig. 3A shows an image 300 which has been obtained from a clinical CT image data set which has been re-projected and noise was added, simulating a dose of 5 mAs. In other words, image 300 illustrates a reconstructed three-dimensional image of a first portion of an object of interest captured with a relatively low radiation dose. The original reconstructed image is shown in Fig. 3 A at level 0 HU and window 1000 HU (HU means Hounsfield unit).
In an image 310 shown in Fig. 3B and in an image 320 shown in Fig. 3C, an edge-preserving filter was applied to image 300. Additionally, the result of a semiautomatic, model-based segmentation of two human femurs 330, 340 and a human bladder 350 are shown.
In the following, referring to Fig.4A and Fig. 4B, a computer tomography apparatus 400 according to an exemplary embodiment of the invention is shown in a first operation mode (see Fig. 4A) and in a second operation mode (see Fig. 4B).
Fig. 4A shows a patient as an object of interest 107 on a mounting table 402. An X-ray source 104 is adapted to irradiate a first portion 404 of the object of interest 107. Electromagnetic radiation emitted by the X-ray source 104 and transmitted through the first portion 404 of the object of interest 107 can be detected by detector 108. The detector 108 is connected to a control unit 118, which is connected to a graphical user interface 401 via which a human user may interfere. Reference number 403 denotes a scanning range along which the operation table 402 is moved with respect to a rotating gantry 101 during taking a helical scan of the first portion 404. During scanning the first portion 404, the radiation source 104 emits X-rays with a relatively low radiation dose.
After having scanned the first region 404, the signals detected by the detec- tor 108 are transmitted to the control unit 118 where a low resolution image of the first portion 404 is calculated and displayed on a monitor of the graphical user interface 401.
Subsequently, as shown in Fig. 4B, a second scan with a larger intensity
of X-rays emitted by the X-ray source 104 is carried out in a second portion 450 of the object of interest 107. Based on the signals acquired during the scan which is taken along the scan range 403 to investigate the first portion 404, a region in an environment of the human heart of the patient 107 is determined. Since this human heart shall be investigated in more detail, the second portion 450 which is limited with respect to the first portion 404 is defined, and this second portion 450 (including the heart) is scanned in a helical manner along a second scan range 451. The results of this scan are detected by the detector 108, wherein the detection signals are transferred to the control unit 118 reconstructing the three-dimensional image of the second portion 450. This three dimen- sionnal portion is displayed in detail on the monitor of the graphical user interface 401. Fig. 5 depicts an exemplary embodiment of a data processing device 500 according to the present invention for executing an exemplary embodiment of a method in accordance with the present invention. The data processing device 500 depicted in Fig. 5 comprises a central processing unit (CPU) or image processor 501 connected to a memory 502 for storing an image depicting an object of interest, such as a patient. The data processor 501 may be connected to a plurality of input/output network or diagnosis devices, such as an MR device or a CT device. The data processor 501 may furthermore be connected to a display device 503, for example a computer monitor, for displaying information or an image computed or adapted in the data processor 501. An operator or user may interact with the data processor 501 via a keyboard 504 and/or other output devices, which are not depicted in Fig. 5. Furthermore, via the bus system 505, it is also possible to connect the image processing and control processor 501 to, for example a motion monitor, which monitors a motion of the object of interest. In case, for example, a lung of a patient is imaged, the motion sensor may be an exhalation sensor. In case the heart is imaged, the motion sensor may be an electrocardiogram (ECG).
Exemplary technical fields, in which the present invention may be applied advantageously, include medical applications, material testing, and material science. A reduced total dose to the patient may be achieved. Also, the invention can be applied in the field of heart scanning to detect heart diseases. It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined.
It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.
Claims
1. A control unit (118) for a computer tomography apparatus (100) for examination of an object of interest (107), wherein the control unit (118) is adapted to control the computer tomography apparatus (100) to detect, by detection elements (123) rotating around the object of interest (107), first electromagnetic radiation signals emitted by an electromagnetic radiation source (104) rotating around the object of interest (107) and passed through a first portion (404) of the object of interest (107); determine, based on the detected first electromagnetic radiation signals, first structural information concerning the first portion (404) of the object of interest (107); determine, based on the first structural information, a second portion (450) of the object of interest (107) as a region of interest; detect, by the detection elements (123) rotating around the object of interest (107), second electromagnetic radiation signals emitted by the electromagnetic radiation source (104) rotating around the object of interest (107) and passed through the second portion (450) of the object of interest (107); determine, based on the second electromagnetic radiation signals, three- dimensional structural information as second structural information concerning the second portion (450) of the object of interest (107); display the three-dimensional structural information.
2. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that the first portion (404) includes the second portion (450) or overlaps the second portion (450).
3. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that a resolution of the first structural information is lower than a resolution of the second structural information.
4. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that a radiation dose emitted by the electromagnetic radiation source (104) for detecting the first electromagnetic radiation signals is lower than a radiation dose emitted by the electromagnetic radiation source (104) for detecting the second electromagnetic radiation signals.
5. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that, for detecting the first electromagnetic radiation signals and the second electromagnetic radiation signals, the electromagnetic radiation source (104) and the detection elements (123) rotate around the object of interest (107) along a circular or a helical trajectory.
6. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that determining the region of interest is performed under consideration of user-defined information provided via a user interface (401).
7. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that determining the region of interest is performed under consideration of pre-stored database information.
8. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that determining the region of interest is performed using a model-based segmentation.
9. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that a three-dimensional structure of the first portion (404) is determined as the first structural information.
10. The control unit (118) according to claim 1, comprising a user- interface (401) being adapted to enable a user to check and/or modify the determined region of interest.
11. The control unit (118) according to claim 1, being adapted to control the computer tomography apparatus (100) in such a manner that a radiation dose emitted by the electromagnetic radiation source (104) for detecting the second electromagnetic radiation signals is adjusted in accordance with pre- stored information concerning the region of interest.
12. The control unit (118) according to claim 1, wherein the second portion (450) of the object of interest (107) is determined as a region of interest in a manual manner or in a semi-automatic manner or in a fully- automatic manner.
13. A computer tomography apparatus (100) for examination of an object of interest (107), wherein the computer tomography apparatus (100) comprises an electromagnetic radiation source (104) adapted to emit electromagnetic radiation to the object of interest (107) and adapted to rotate around the object of interest (107); detecting elements (123) adapted to detect electromagnetic radiation emitted by the electromagnetic radiation source (104) and passed through the object of interest (107) and adapted to rotate around the object of interest (107); and a control unit (118) according to claim 1.
14. The computer tomography apparatus (100) according to claim 13, comprising a collimator (105) arranged between the electromagnetic radiation source (104) and the detecting elements (123), the collimator (105) being adapted to collimate an electromagnetic radiation beam emitted by the electromagnetic radiation source (104) to form a fan-beam or a cone -beam.
15. The computer tomography apparatus (100) according to claim 13, wherein the detecting elements (123) form a single-slice detector array.
16. The computer tomography apparatus (100) according to claim 13, wherein the detecting elements (123) form a multi- slice detector array (108).
17. The computer tomography apparatus (100) according to claim 13, configured as one of the group consisting of a medical application apparatus, a material testing apparatus and a material science analysis apparatus.
18. A method of examining an object of interest (107) with a computer tomography apparatus (100), the method comprising the steps of detecting, by detection elements (123) rotating around the object of interest (107), first electromagnetic radiation signals passed through a first portion (404) of the object of interest (107); determining, based on the detected first electromagnetic radiation signals, first structural information concerning the first portion (404) of the object of interest (107); determining, based on the first structural information, a second portion (450) of the object of interest (107) as a region of interest in a semi-automatic manner or in a fully- automatic manner; detecting, by the detection elements (123) rotating around the object of interest (107), second electromagnetic radiation signals passed through the second portion (450) of the object of interest (107); determining, based on the second electromagnetic radiation signals, three- dimensional structural information as second structural information concerning the second portion (450) of the object of interest (107) display the three-dimensional structural information.
19. A computer-readable medium (502), in which a computer program of examining an object of interest (107) is stored which, when being executed by a processor (501), is adapted to carry out the steps of detecting, by detection elements (123) rotating around the object of interest
(107), first electromagnetic radiation signals passed through a first portion (404) of the object of interest (107); determining, based on the detected first electromagnetic radiation signals, first structural information concerning the first portion (404) of the object of interest (107); determining, based on the first structural information, a second portion (450) of the object of interest (107) as a region of interest in a semi-automatic manner or in a fully- automatic manner; detecting, by the detection elements (123) rotating around the object of interest (107), second electromagnetic radiation signals passed through the second portion (450) of the object of interest (107); determining, based on the second electromagnetic radiation signals, three-dimensional structural information as second structural information concerning the second portion (450) of the object of interest (107); display the three-dimensional structural information.
20. A program element of examining an object of interest (107), which, when being executed by a processor (501), is adapted to carry out the steps of detecting, by detection elements (123) rotating around the object of interest (107), first electromagnetic radiation signals passed through a first portion (404) of the object of interest (107); determining, based on the detected first electromagnetic radiation signals, first structural information concerning the first portion (404) of the object of interest (107); determining, based on the first structural information, a second portion (450) of the object of interest (107) as a region of interest in a semi-automatic manner or in a fully- automatic manner; detecting, by the detection elements (123) rotating around the object of interest (107), second electromagnetic radiation signals passed through the second portion (450) of the object of interest (107); determining, based on the second electromagnetic radiation signals, three- dimensional structural information as second structural information concerning the second portion (450) of the object of interest (107) display the three-dimensional structural information.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP05101349 | 2005-02-23 | ||
| EP05101349.8 | 2005-02-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2006090321A1 true WO2006090321A1 (en) | 2006-08-31 |
Family
ID=36587330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2006/050542 WO2006090321A1 (en) | 2005-02-23 | 2006-02-20 | Determination of the coverage of a ct scan |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2006090321A1 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008119555A1 (en) * | 2007-04-03 | 2008-10-09 | Carl Zeiss Industrielle Messtechnik Gmbh | Method and measuring arrangement for producing three-dimensional images of measuring objects by means of invasive radiation |
| CN103519789A (en) * | 2013-10-24 | 2014-01-22 | 中国科学院自动化研究所 | Separating type imaging system integrating opto-acoustic and X-ray tomography |
| CN103690244A (en) * | 2013-12-24 | 2014-04-02 | 中国科学院自动化研究所 | Imaging system for fusing photo-acoustic imaging and X-ray tomography |
| EP2665035A3 (en) * | 2009-02-20 | 2016-12-07 | Werth Messtechnik GmbH | Method for measuring an object |
| WO2017103037A1 (en) * | 2015-12-17 | 2017-06-22 | Koninklijke Philips N.V. | Method and device for a medical image analysis |
| DE102016204212A1 (en) * | 2016-03-15 | 2017-09-21 | Siemens Aktiengesellschaft | Computed tomographic method and apparatus for carrying it out |
| EP3679862A1 (en) * | 2019-01-09 | 2020-07-15 | Koninklijke Philips N.V. | Adaptive helical computed tomography |
| CN116019474A (en) * | 2023-02-22 | 2023-04-28 | 有方（合肥）医疗科技有限公司 | Multi-source imaging device and method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000062675A1 (en) * | 1999-04-15 | 2000-10-26 | General Electric Company | Optimized ct protocol |
| US20030076920A1 (en) * | 2001-10-18 | 2003-04-24 | Toshiyuki Shinno | X-ray computed tomography apparatus |
| US20040202283A1 (en) * | 2002-11-29 | 2004-10-14 | Kabushiki Kaisha Toshiba | X-ray CT apparatus |
-
2006
- 2006-02-20 WO PCT/IB2006/050542 patent/WO2006090321A1/en not_active Application Discontinuation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000062675A1 (en) * | 1999-04-15 | 2000-10-26 | General Electric Company | Optimized ct protocol |
| US20030076920A1 (en) * | 2001-10-18 | 2003-04-24 | Toshiyuki Shinno | X-ray computed tomography apparatus |
| US20040202283A1 (en) * | 2002-11-29 | 2004-10-14 | Kabushiki Kaisha Toshiba | X-ray CT apparatus |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008119555A1 (en) * | 2007-04-03 | 2008-10-09 | Carl Zeiss Industrielle Messtechnik Gmbh | Method and measuring arrangement for producing three-dimensional images of measuring objects by means of invasive radiation |
| DE102007016370A1 (en) * | 2007-04-03 | 2008-10-09 | Carl Zeiss Industrielle Messtechnik Gmbh | Method and a measuring arrangement for generating three-dimensional images of test objects by means of invasive radiation |
| EP2665035A3 (en) * | 2009-02-20 | 2016-12-07 | Werth Messtechnik GmbH | Method for measuring an object |
| CN103519789A (en) * | 2013-10-24 | 2014-01-22 | 中国科学院自动化研究所 | Separating type imaging system integrating opto-acoustic and X-ray tomography |
| CN103690244A (en) * | 2013-12-24 | 2014-04-02 | 中国科学院自动化研究所 | Imaging system for fusing photo-acoustic imaging and X-ray tomography |
| CN103690244B (en) * | 2013-12-24 | 2016-08-10 | 中国科学院自动化研究所 | A kind of optoacoustic and the imaging system of x-ray tomography imaging fusion |
| WO2017103037A1 (en) * | 2015-12-17 | 2017-06-22 | Koninklijke Philips N.V. | Method and device for a medical image analysis |
| CN108472002A (en) * | 2015-12-17 | 2018-08-31 | 皇家飞利浦有限公司 | Method and apparatus for medical image analysis |
| DE102016204212A1 (en) * | 2016-03-15 | 2017-09-21 | Siemens Aktiengesellschaft | Computed tomographic method and apparatus for carrying it out |
| EP3679862A1 (en) * | 2019-01-09 | 2020-07-15 | Koninklijke Philips N.V. | Adaptive helical computed tomography |
| WO2020144124A1 (en) | 2019-01-09 | 2020-07-16 | Koninklijke Philips N.V. | Adaptive helical computed tomography |
| US11890127B2 (en) | 2019-01-09 | 2024-02-06 | Koninklijke Philips N.V. | Adaptive helical computed tomography |
| CN116019474A (en) * | 2023-02-22 | 2023-04-28 | 有方（合肥）医疗科技有限公司 | Multi-source imaging device and method |
| CN116019474B (en) * | 2023-02-22 | 2023-09-19 | 有方（合肥）医疗科技有限公司 | Multi-source imaging device and method |
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