RU2325117C2 - Topographometric system with tomography function - Google Patents

Abstract

FIELD: medicine; medical diagnostic technique.

SUBSTANCE: topographometric system with topography function contains X-ray emitter, profondometer, rotational console, mechanism for moving of the profondometer along console, device for detection of X-ray radiation as a detectors scale, moving mechanism for detection device, table for the patient with radiotransparent deck, stand with rotation drive for console, data transmitter to the electronic computer, analog-digital converters and management system. Profondometer scanning contains flat-field collimator graving from the opening of operating beam narrow fan-shaped beam. It also has drive which provides moving synchrony of the beam and device for X-ray radiation detection containing crate with detectors scale. It is mounted on the movable carriage of the mechanism for moving of the detecting device with the ability of rocking about the axis and fitted with driver, providing the orientation of the scale on the focus point in any position of the carriage. Detectors scale radius in the central position is equal to the distance from the focus point to the central scale in the tomography mode. Mechanism for the moving of detectors device is switched in the synchronization device, which is made with the capability of crate orientation according the position of flat-field collimator so that the detectors scale is located in the flat of fan-shaped beam and crate aperture is oriented on the focus point of the X-ray tube.

EFFECT: development of the sphere of potential focal disease detecting among the oncology patients at one testing.

3 cl, 6 dwg

Description

The proposed device relates to the field of medical diagnostic equipment and is intended to obtain projection x-ray images of the patient’s body in the geometry of the therapeutic unit (distance “source-surface of the body” RIP, distance “source-axis of rotation” of the RIO, the projection of the boundaries of the radiation body, the position of the laying table, etc. .p.) in the process of preradiation topometric preparation of cancer patients.

A known radiation system for generating images and a method for its implementation [1], providing a flat image of the body of the test patient. The system includes an irradiation source, a laying table for fixing the patient’s body in different positions, a computer system for receiving, processing and transmitting projection images, a device for storing received images and a device for modeling the irradiation source. The known system and method of its use can provide many tomographic positions from the rotational view of the patient’s body, which provides a three-dimensional comprehensive view of his condition. However, the known system does not allow to obtain a sufficiently high quality of complete information to reduce radiation dose values.

Known therapeutic simulator [2], which contains a radiation source located in the head of the radiator. The simulator has a device that controls the size of the diaphragm, and a device that provides such regulation that allows you to make the design of the patient’s body more compact and allows you to get more information with a single dose of radiation and with a simpler design. However, the known device has a fairly high dose load during the examination and a limited area of reconstruction.

Known computer tomograph using an image intensifier sensor [3], closest to the proposed invention to achieve a technical result and design and adopted as a prototype. A well-known computed tomograph contains an x-ray emitter, an x-ray head, a rotation console, a device for moving the x-ray head along the console, a device for detecting the x-ray radiation transmitted through the patient’s body, a mechanism for moving the detection device, a table for laying down the patient with an X-ray transparent deck, a bed with a rotation drive of the console. Multichannel photosensors allow producing statistical limited images. Used software minimizes geometric distortion.

The disadvantages of the known device are the high cost of the diagnostic system, a limited area of reconstruction, a sufficiently high dose load on the patient during his examination.

The present invention is devoid of these disadvantages.

The technical result of the invention is the creation of a significantly cheaper diagnostic topometric system with a tomography function compared to foreign counterparts, which at the same time will significantly expand the area of detection of potential foci of cancer patients in one study, thereby excluding its reusable irradiation, as well as with high accuracy and reliability, the planned maximum sparing radiation doses during research and therapy, as well as It is possible to obtain transverse reconstructive (computational) tomograms at selected levels of the patient’s body. The data obtained are used to simulate radiation in a therapeutic unit and to calculate the dose fields of a therapeutic beam when planning radiation (radiation) therapy. In addition, the claimed invention allows verification (control of the accuracy of the patient’s styling) and the calculated exposure plan.

The specified technical result is achieved by the fact that in the proposed topometric system with a tomography function comprising an x-ray emitter, an x-ray head, a rotation console, a device for moving the x-ray head along the console, a device for detecting x-ray radiation transmitted through the patient’s body, a mechanism for moving the detection device, a table for laying a patient with an X-ray deck, a bed with a rotation drive of the console, in accordance with the invention, X-ray The ova head contains a scanning slotted collimator that cuts a narrow fan beam from the aperture of the working beam, the slotted collimator is equipped with a drive that ensures synchronous movement of the beam and the recording element, an X-ray detection device that moves synchronously with the scanning slotted collimator, contains a crate suspended from a movable carriage with the possibility of swing around an axis passing through the central detector, and equipped with a drive that ensures the orientation of the ruler to the focal point At any position of the carriage, a recording element, a secondary slit collimator, a device for transferring data to an electronic computing device, a line of detectors is used as a recording element, the radius of the line in the central position is equal to the distance from the focal point to the center of the line in tomography mode, analog-to-digital converters , a control system for data collection, synchronization of movement of an X-ray detection device and a slotted collimator is provided by a synchronization device an orientation providing the orientation of the crate depending on the position of the slit collimator so that the line of detectors is always located in the plane of the fan beam and at various distances from the focal point of the x-ray tube to the isocentric axis.

In addition, this technical result is achieved by the fact that in the proposed topometric system, the synchronization device is made in the form of mechanical rods forming parallelograms having a common vertex located at the focal point of the x-ray tube and extended beyond the patient’s laying area towards the rotational console, one of the parallelograms formed by the slit collimator rod, the second parallelogram is formed by the rod on which the crate is fixed, the third parallelogram is formed by the inclined rod crete.

In addition, this technical result is achieved by the fact that in the proposed topometric system, the synchronization device is made in the form of servos located in the x-ray head and on the movable carriage, providing movement of the slotted collimator and the slope of the crate.

The essence of the proposed device is illustrated in figures 1-4. Figure 1 presents a General view of the proposed device. Figure 2 - x-ray block, slotted collimator with a drive system. Figure 3 - block diagram of a simulator of the irradiation field of the proposed topometric system with the function of the tomograph. Figure 4 - diagram of the crate of the data acquisition system.

The proposed device (Fig. 1) consists of a bed with a drive for rotating the console (1), the rotation console (2) (the rotation console includes the console of the X-ray unit (3), the movement mechanism of the detection device (4), the synchronizing lever system (5)), an x-ray emitter (6), an x-ray head (7), a device for detecting x-ray radiation (8) passing through the patient’s body, a table for laying a patient with an x-ray transparent deck (9). The synchronizing device is made in the form of servos placed in the x-ray head and on the movable carriage; in fact, this is a system of mechanical rods forming parallelograms that have a common vertex located at the focal point of the x-ray tube and extended beyond the patient’s laying area towards the rotational console. One of the parallelograms (ABCD) is formed by the slit collimator rod, the second (ABC'D ') is formed by the rod on which the X-ray detection device is mounted (8), the third parallelogram (ABC''D' ') is formed by the rod, which ensures the inclination of the X-ray detection device radiation (8).

The x-ray head contains a scanning slotted collimator (10) (Fig. 2), equipped with a drive providing synchronization of the beam movement of the recording element mounted on the movable carriage (11) (the carriage is equipped with a movement drive (12) of the slotted collimator (10)), the main aperture diaphragm (13), radiation field simulators (14) and (15) (Fig. 3), a guard ring of the anti-collision system (16) (Fig. 3), a removable radiopaque central cross (17) (Fig. 3).

An X-ray detection device moved synchronously with a scanning slotted collimator comprises a crate shown in FIG. 4. The rack (18) is suspended on a movable carriage with the possibility of swinging around an axis passing through the central detector, and is equipped with a drive that ensures the orientation of the ruler to the focal point at any position of the carriage. A recording element is installed in the crate (18) - a line of solid-state detectors (19), such as scintillator-photodiode; the radius of the ruler in the central position is equal to the distance from the focal point to the center of the ruler, a secondary slit collimator (20), analog-to-digital converters (ADCs) (21), a data acquisition control system, and a data transmission device to an electronic computing device (22).

The work of the proposed device is carried out in the modes of a projection x-ray digital image and transverse x-ray computer tomograms.

The projection image is based on the principle of “scanning slit”: a slit collimator (10) cuts out a flat fan beam from a wide X-ray beam, which, after passing through the patient’s body, is detected by a radiation detection device (8); when the slotted collimator (10) is moved, a scanning x-ray beam is formed. Synchronized coordinated movement of the beam and the line of detectors (19) is ensured by kinematic coupling. The kinematic connection (5) of the slit collimator (10) of the X-ray head (7), the rack (18), the carriage of the rack, which is part of the movement mechanism (4) of the detection device (8), moves the slotted collimator (10) in accordance with the axis (C ') the suspension of the rack (18) and the coordinated change in the angle of inclination of the line of detectors (19). The rack (18) is suspended on the carriage, which is part of the movement mechanism (4), and tilts depending on the position of the carriage so that its aperture is oriented to the focal point of the x-ray tube. Structural elements that ensure the implementation of the kinematic connection are taken out of the patient's placement area so as not to limit the possibilities of its laying on a therapeutic table with an X-ray transparent deck (9). When changing the position of the rod AD '', the position of the tie points DC, D'C ', D``C' 'fixed on the rod changes simultaneously. The rod DC moves the slotted collimator (10), rod D'C 'moves the rack (18) with a line of detectors (19), and rod D''C' 'of the synchronization system (5) sets the slope of the rack (18) according to the principle " parallelogram. "

The beam passing through the patient’s body is recorded by detectors (19), the signal from which is converted using digital-to-analog converters [ADC (21)] into a digital code and transmitted to reconstruct the image to a computer. The scanning process starts from the initial position of the synchronizing linkage system (5) and the X-ray detection device (8), shown in Fig. 1 as a solid line, and ends in the final position, shown as a dashed line (Fig. 1).

In a topometric system, synchronized coordinated movement of the beam and the rack (18) with a line of detectors (19) can also be implemented on the basis of servo drives containing motion sensors and servomotors controlled from a computer. Communication in this case is provided by a computer program that implements the principle of "parallelogram".

Obtaining transverse tomograms is based on the transmission of the patient by a rotating fan beam in the geometry of a third generation computer tomograph (rotational-rotational tomograph). The focal point of the tube (6) and the line of detectors (19) rotate synchronously around the patient. During rotation of the rotation console (2), its rotation angle and intensity distribution of the x-ray beam transmitted through the patient’s body are recorded. To take a tomogram, the movement mechanism of the detection device (8) is set to the middle position at which the fan beam is perpendicular to the axis of rotation of the rotation console (2). Based on the projections of the patient being measured at different angles, the computed tomography method reconstructs the image of the patient’s body cross section, on the basis of which radiation therapy planning for cancer patients is planned. In addition, when planning radiation (radiation) therapy, the proposed device allows the minimum necessary (gentle) calculation of the dose fields of a therapeutic beam by obtaining more complete information, including transverse reconstructive (computational) tomograms for different selected levels of the patient's body; the data obtained are previously used to simulate radiation in a therapeutic unit.

A beam passing through the patient’s body is recorded by detectors, which are a line of solid-state scintillator-photodiode detectors. The signal of the detectors using the ADC is converted into a digital code and transmitted for image reconstruction to a computer (Figs. 5, 6, which show projection images of digital information).

Thus, the claimed topometric system with a tomography function due to the original execution of the kinematic connection of the main nodes of the device and software allows you to:

- receive projection x-ray images of the patient’s body in the geometry of the therapeutic unit (the source-surface of the body RIP, the source-axis of rotation of the RIO, the projection of the boundaries of the irradiation body, the position of the laying table, etc.) in the course of preradiation topometric preparation of oncological sick people;

- receive transverse reconstructive (computational) tomograms at selected levels of the patient’s body, which are used to simulate radiation in a therapeutic unit and calculate the dose fields of a therapeutic beam when planning radiation (radiation) therapy;

- carry out verification (control of the accuracy of patient placement) and the calculated exposure plan.

The most important advantages of the proposed device, in comparison with the prototype, should include:

1. The maximum increase in the diameter of the reconstruction region of the image of the topometric projection of the patient due to the increase in the area of transillumination, which allows for full telemetry imaging of large patients who do not fit into standard European equipment (Fig.6, which is presented).

2. A significant reduction in the radiation dose to the patient during examination, which was made possible by the use of a new ruler design, which, in combination with other elements of the device, can absorb up to 95% of X-ray radiation by detectors.

3. A significant increase in information content and image quality by reducing the contribution of scattered radiation.

4. Reducing the examination time by obtaining tomograms for up to 30-35 s.

4. Automation of the transition from the projection image mode to tomography (while in the prototype the amplifier gives only the projection image and the transition to tomography of the prototype is very difficult).

5. Reduced installation costs due, in particular, to the use of one recording element (instead of two, the prototype). The cost of one such element is about 150 thousand US dollars. The cost of one of the most advanced telemetry systems technology of Philips company is 1 million 200 thousand US dollars. In developed countries, one such installation, in order to prevent, prevent and timely diagnose cancer, is calculated on average per 100 thousand people. In our country, this is not a comparable indicator for the number of diagnosed population.

However, I would like to note that the cost of the proposed installation is about two times lower, and such indicators as the reconstruction area (60), where the image is obtained; free space where patients can be accommodated (95), tomogram acquisition time (30); contrast resolution - superior in similar indicators to the telemetry system of the same company "Philips".

The lower cost of the proposed installation and its higher quality indicators could make it possible for the population of Russia (currently 1 topometric system in the Russian Federation, on average, for 1-2 million people) such a necessary and important system for improving the nation prophylactic-oncodiagnostic examination.

Information sources

1. US patent No. 5247555 "Radiation image generating system and method".

2. US patent No. 4943990 "Therapy simulator".

3. WO 92/00567 "Computer tomografy apparatus using image intensifier detector" (prototype).

Claims (3)

1. A topometric system with a tomography function comprising an X-ray emitter, an X-ray head, a rotation console, a device for moving the X-ray head along the console, an X-ray detection device in the form of a line of detectors, a mechanism for moving the detection device, a table for laying down a patient with an X-ray transparent deck, a bed with rotational drive of the console, a device for transmitting data to an electronic computing device, analog-to-digital converters and a control system, about characterized in that the x-ray head contains a scanning slit collimator that cuts out a narrow fan beam from the aperture of the working beam, equipped with a drive that provides synchronous movement of the beam and the X-ray detection device, containing a rack with a line of detectors, and a swinging mechanism of the detection device suspended on a movable carriage around an axis passing through the central detector of the ruler and equipped with a drive that ensures the orientation of the ruler to the point f piece at any position of the movable carriage, the radius of the line of detectors in the central position is equal to the distance from the focal point to the center of the line in the tomography mode, and the movement mechanism of the detection device is included in the synchronization device configured to orient the crate depending on the position of the slot collimator so that the line the detectors are located in the plane of the fan beam, and the crate aperture is oriented to the focal point of the x-ray tube. 2. The topometric system according to claim 1, characterized in that the synchronization device is made in the form of mechanical rods forming parallelograms having a common vertex located at the level of the ficus point of the x-ray tube and extended beyond the patient’s laying area towards the rotation console, one of the parallelograms is formed the traction of the slotted collimator, the second parallelogram is formed by the traction on which the crate is fixed, the third parallelogram is formed by the traction, which ensures the tilt of the crate. 3. The topometric system according to claim 1, characterized in that the synchronization device is made in the form of servos located in the x-ray head and on the movable carriage.

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