JP2005334383A - Radiotherapy apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly precisely position radiation for treatment at an affected part in a radiotherapy apparatus. <P>SOLUTION: The radiotherapy apparatus 100 has an irradiation nozzle 101 for irradiating a patient with radiation. An image including the affected part 16 of the patient 15 is photographed by image acquiring devices 11a-12b. The image acquiring devices comprise at least two pairs of radiation sources 11a and 12a and detectors 11b and 12b for detecting images photographed with the radiation emitted from the radiation sources. The irradiation nozzle comprises index parts 14a and 14b to be photographed in the images photographed by the image acquiring devices. The irradiation nozzle is positioned by using the images of the index parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radiation treatment system for treatment using radiation.

  An example of a conventional radiotherapy apparatus is described in Patent Document 1. In the radiation apparatus described in this publication, the X glands emitted from the radiation source are crossed with each other at the examination target part in order to accurately track the radiation irradiation target part. Then, X-rays transmitted through the inspection target part are detected by a detector, and the image forming apparatus creates a three-dimensional image of the inspection target part. At that time, the control device changes the shape of the emission port of the emission port variable collimator, and changes the X-ray irradiation field emitted from the radiation generation device by tracking the position and shape of the treatment target region.

JP 2003-220151 A

  In the radiotherapy apparatus described in Patent Document 1, the position of the affected area can be accurately identified. However, the accuracy of specifying the irradiation direction of the therapeutic radiation and the relative position of the affected area depends on the accuracy of each component of the radiotherapy apparatus. . In other words, in order to increase the specific accuracy, each component is manufactured with high accuracy, and the amount of deformation that each component deforms due to a load including heat and its own weight is accurately grasped. It is necessary to control the correction. At this time, since the deformation amount is the sum of the deformations of the respective component parts, the deformation amount must be accurately grasped at the individual component level.

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to position therapeutic radiation at an affected area of a patient with high accuracy.

  A feature of the present invention that achieves the above object is that a radiation therapy apparatus includes an irradiation nozzle that irradiates a patient with radiation, and an image acquisition apparatus that captures an image including an affected part of the patient. There are at least two pairs of detectors for detecting a captured image by radiation emitted from a radiation source, and the irradiation nozzle has an index portion that can be reflected in an image captured by the image acquisition device. Means for positioning an irradiation nozzle using an image is provided.

  In this feature, the imaging apparatus is provided with a moving mechanism that can be photographed simultaneously from two different directions and that can move the indicator portion relative to the irradiation nozzle. The means for detecting contact with the patient in the indicator portion And a mechanism that allows the indicator portion to move relative to the irradiation nozzle based on the output of the contact detection means.

  Further, the image acquisition device can acquire on the same image the index part and the reference that can specify the affected part or the affected part position, and the radiation direction of the therapeutic radiation and the affected part or the affected part based on the image captured by the image acquiring apparatus It is desirable to provide a means for calculating a target position and a target posture of a treatment table on which a patient is placed and a irradiation nozzle based on the relative position, by obtaining a reference relative position capable of specifying the position.

  Further, the position of the index portion is calculated from the image of the index portion captured by the image acquisition device, and a means for positioning the irradiation position of the irradiation nozzle is provided on the affected area, based on the image of the index portion captured by the image acquisition device Means may be provided for determining whether or not to apply radiation.

  According to the present invention, since the X-ray marker is attached to the gantry which is the radiation irradiation means, the overall relative positional deviation between the position or direction of the radiation irradiated by the radiation irradiation means and the affected part is directly measured. Since it can be grasped, radiation can be irradiated to the affected area with high accuracy.

  An embodiment of a radiation therapy apparatus 100 according to the present invention will be described with reference to the drawings. In these figures, bones and internal organs are not shown for simplicity. The radiation therapy apparatus 100 irradiates the affected part 16 of the patient 15 with therapeutic radiation (proton beam). The patient 15 is placed on the treatment table 13. The image acquisition devices 11a to 12b are arranged so as to surround the affected area of the patient 15, and a practitioner (not shown) determines images taken by the image acquisition devices 11a to 12b. When performing this operation, it is necessary to position the radiation irradiation position on the affected part 16 with high accuracy, and the control device of the radiation therapy apparatus 100 positions the radiation emitting means 10 using the markers (indicator parts) 14a and 14b. . A specific example of this will be described with reference to the radiotherapy apparatus 100 shown in a perspective view in FIG. 1 and FIG. 2 which is an example of an image taken by the radiotherapy apparatus 100.

  The radiotherapy apparatus 100 is provided above the patient 15 and includes an irradiation nozzle 10 that irradiates the patient 15 with therapeutic radiation 17. The irradiation nozzle 10 can be swung around an axis in the front-rear direction as indicated by an arrow 18 by a rotational movement means (not shown).

  The patient 15 is placed on a treatment table 13 facing the irradiation nozzle 10 and positioned below the irradiation nozzle 10. The treatment table 13 is movable in the up-down direction and the front-rear, left-right direction. A pair of image acquisition devices 11 a and 11 b are arranged on both the left and right sides of the patient 15 so as to face each other. The image acquisition device 11a is a radiation source, and the image acquisition device 11b, which is a detector, detects the radiation for imaging emitted from the radiation source 11a. Another pair of image acquisition devices 12a and 12b are arranged so that the radiation 18b that obliquely intersects the affected area 16 with respect to the radiation 18a emitted from the image acquisition device 11a is formed. That is, the image acquisition device 12a that is a radiation source is below and in front of the image acquisition device 11a, and the image acquisition device 12b that is a detector is above and behind the image acquisition device 11b. The image acquisition devices 12a and 12b are opposed to each other. Since the two pairs of image acquisition devices 11a to 12b are arranged, the three-dimensional position of the affected part 16 can be specified.

  Two indicator portions 14 a and 14 b having different heights are attached around the tip of the irradiation nozzle 10. One indicator portion 14 a is attached to the front side surface of the irradiation nozzle 10, and the other indicator portion 14 b is attached to the right side surface portion of the irradiation nozzle 10. The index parts 14a and 14b are made of a material that can be detected by the image acquisition devices 11a to 12b, and are made of a material having a transmittance different from that of, for example, a bone or an organ. The index parts 14a and 14b are determined from the images 20a and 20b taken by the image acquisition devices 11a to 12b. In order to grasp the positions of both the affected part 22 and the index parts 21a, 21b from the images 20a, 20b taken by the image acquisition devices 11a-12b, The radiation therapy apparatus 100 is provided with a calculation means for calculating the positions of the index parts 14a and 14b.

  In other words, the affected part 16 and the index parts 14a and 14b taken from a different direction from the image 20a are shown in the image 20b taken by the image acquisition devices 12a and 12b. In the two images 20a and 20b, the affected part 16 is displayed as the affected part image 22, the index part 14a is displayed as the index part image 21a, and the index part 14b is displayed as the index part image 21b.

  In the image 20a photographed by the detector 11b photographed almost from the side of the patient, the center of the affected part 22 in the height direction is located at the position L2a below the therapeutic radiation 17. Similarly, in the image 20b photographed by the detector 12b, the center in the height direction of the affected part 22 is located at a position below the therapeutic radiation 17 L2b. At this time, the height position of the therapeutic radiation 17 is calibrated in advance using the positions of the indicator portions 14a and 14b. In the image 20a, the horizontal direction center 23 of the index portion 21b and the therapeutic radiation 17 coincides, and the horizontal center L1a of the affected part 22 is shifted to the right from this center 23. In the image 20b, the horizontal center of the affected part 22 is shifted to the right by the therapeutic radiation center 23 by L1b.

  Here, since the mutual positional relationship between the therapeutic radiation 17 and the indicator portions 14a and 14b is measured in advance, the positions of the indicator portions 21a and 21b reflected in the images 20a and 20b taken from two different directions and From the shape, the relative relationship between the index parts 14a and 14b and the affected part 16 can be obtained. Based on the calculated deviation amounts L1a to L2b of the therapeutic radiation 17 of the affected part 16 from the irradiation target center 23 and the height, the movement target amounts of the irradiation nozzle 10 and the treatment table 13 are corrected.

  When obtaining the relative relationship between the affected part 16 and the index parts 14a and 14b, if the three-dimensional image shown in FIG. 3 is created using the images 20a and 20b taken by the image acquisition devices 11a to 12b, the affected part is more visually observed. The 16 positions can be easily determined and the treatment can be speeded up. In FIG. 3, the distance in the height direction between the affected part image 31 and the therapeutic radiation 17 is L3, and the distance in the left-right direction between the therapeutic radiation 17 and the affected part image 31 is represented by L4. The therapeutic radiation 17 is virtually indicated by a broken line, and the index portions 14a and 14b are represented by index portion images 30a and 30b, respectively.

  In this embodiment, two index parts 14a and 14b are provided to create a three-dimensional image. However, two index parts are not necessarily required, and a reference is used when specifying a position from the acquired images 20a and 20b. It suffices if there are two or more parts. In addition, the indicator portions 14a and 14b are not limited to rod-like objects, but may be made of a material that can be detected by the image acquisition devices 11a to 12b or a paint that can be detected by X-rays on the object surface. .

  When the irradiation nozzle 10 and the affected part 16 are close to each other and a radiation transmitting material can be used for the irradiation nozzle 10, a material that can be detected by the image acquisition devices 11 a to 12 b can be directly attached to the irradiation nozzle 10. Moreover, you may apply a coating material. Furthermore, in the present embodiment, the image acquisition devices 11a to 12b detect the affected area 16, but when the image acquiring apparatuses 11a to 12b cannot detect the affected area, a reference that can specify the position of the affected area 16, for example, a bone Alternatively, the positional relationship between the affected part 16 and the irradiation target center 23 of the therapeutic radiation 17 may be calculated by detecting a marker attached to the body.

  Another embodiment of the radiation therapy apparatus 100 according to the present invention is shown in FIG. The present embodiment is different from the above embodiment in that the indicator portions 14 a and 14 b can be moved using the link mechanism 44. Other configurations are the same as those in the above embodiment. The indicator portions 14a and 14b are movable by the link mechanism 44 from a position indicated by a solid line 42 to a position 43 indicated by a broken line. A sensor is provided at the distal end portion of the link mechanism 44, and a signal is sent from this sensor to the detector 45 to detect the distal end positions of the indicator portions 14a and 14b. In the present embodiment, the sensor is provided at the tip of the indicator portions 14a and 14b. However, the position detector 45 may be provided directly on the link mechanism 44 to calculate the tip position of the indicator portion 42. This method is effective when the patient contacts the indicator portions 14a and 14b. A spring can also be used as the moving means of the indicator portions 14a and 14b. In addition, the indicator portions 14 a and 14 b may be detachable from the irradiation nozzle 10.

  In the embodiment shown in FIG. 4, the relative position between the therapeutic radiation 17 and the affected area 16 is obtained based on the outputs of the sensors provided in the index sections 14a and 14b, but the contact position detecting means is provided in the index sections 14a and 14b. The irradiation nozzle 10 and the treatment table 13 may be positioned and controlled using the position detected by the contact position detecting means. For example, if the irradiation nozzle 10 and the treatment table 13 are stopped when the contact position detection means detects contact, damage to the patient and peripheral devices can be prevented. An actuator may be provided in the indicator portions 14a and 14b, and when the indicator portions 14a and 14b come into contact with a patient or the like, the indicator portions 14a and 14b may be retracted to a safe position.

  In each of the above embodiments, a method of positioning the therapeutic radiation 17 on the affected part 16 will be described with reference to FIGS. These drawings are block diagrams of the radiation therapy apparatus 100. Image signals taken by the image acquisition device 50 having the image acquisition units 11 a and 11 b and the image acquisition unit 51 having the image acquisition units 12 a and 12 b are sent to the position calculation unit 52. This image signal includes a signal that can specify the index part and the affected part or the position of the affected part. The position calculation means 52 performs image processing using previously known index portions 14a and 14b and the position information of the therapeutic radiation 17, and calculates the irradiation position and posture of the therapeutic radiation 17 and the position of the affected area 16.

  Based on the signal calculated by the position calculating means 52, the control command value calculating means 53 calculates the movement amount of the irradiation nozzle 10 and the treatment table 16 necessary for accurately irradiating the affected part with the therapeutic radiation 17. That is, the movement amount of the irradiation nozzle 10 is transmitted to the irradiation nozzle control device 54, and the sixteenth movement amount in the front / rear and left / right directions is transmitted to the treatment table control device 55. The irradiation nozzle 10 and the treatment table 16 move based on the sent command signals. When the irradiation position of the therapeutic radiation 17 and the affected part 16 treatment position match, the therapeutic radiation 17 is irradiated to the affected part 16.

  Another example of positioning is shown in FIG. This embodiment is different from the case shown in FIG. 5 in the processing method of the information calculated by the position calculating means 52. When the difference between the irradiation position of the therapeutic radiation 17 calculated by the position calculation means 52 and the position of the affected part 16 is equal to or less than a predetermined value, the determination means 63 determines whether radiation irradiation is possible. When irradiating with radiation, a signal indicating that irradiation is possible is sent to the irradiation control device 64, so that therapeutic radiation can be irradiated. This embodiment is effective when the irradiation position accuracy is always managed with high accuracy or when it is used as a device for monitoring the irradiation position.

  Although the positioning of the irradiation nozzle 10 has been described in the above embodiment, the radiation therapy apparatus 100 can be used to measure the movement trajectory of the irradiation nozzle 10. The irradiation nozzle 10 is difficult to accurately move according to the design value due to various factors such as installation error, mechanism play, and deformation. Therefore, the trajectories of the indicator portions 14a and 14b are measured while moving the irradiation nozzle 10 at the time of installation of the apparatus or during periodic inspection. The relationship between the stop position of the irradiation nozzle 10 and the radiation position and posture of the therapeutic radiation is obtained in advance, and the irradiation position and posture are calculated from the mutual relationship during treatment.

  According to each of the above embodiments, the radiotherapy apparatus includes imaging means for imaging the affected area from two different directions, and an indicator for positioning the therapeutic radiation that is imaged together with the affected area when imaged from each direction. The therapeutic radiation can be positioned on the affected area with high accuracy. Further, since the affected area can be irradiated with radiation with high accuracy using a simple device, complicated control means such as manufacturing the configuration mechanism of the radiotherapy device with high accuracy and error correction control for deformation of the mechanism are unnecessary. As a result, the manufacturing cost of the radiation therapy apparatus can be reduced. Further, the relative positional deviation between the therapeutic radiation and the affected part can be confirmed directly, and the radiotherapy can be performed quickly.

The perspective view of one Example of the radiotherapy apparatus which concerns on this invention. The image example of the radiotherapy apparatus which concerns on this invention. An example of a calculated three-dimensional image. The figure explaining the attachment method of a parameter | index part. The control block diagram of the radiotherapy apparatus shown in FIG. The control block diagram of the other Example of the radiotherapy apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Irradiation nozzle, 11a, 11b, 12a, 12b ... Image acquisition device, 13 ... Treatment table, 14a, 14b ... Indicator part, 15 ... Patient, 16 ... Affected part, 17 ... Radiation for treatment, 18 ... Direction of movement, 20 ... Captured images, 21a, 21b ... index part image, 22 ... affected part image, 23 ... irradiation target center, 30a, 30b ... index part image, 31 ... affected part image, 42, 43 ... index part position, 44 ... link mechanism, 45 ... Position detector, 50, 51 ... Image acquisition device, 52 ... Position calculation means, 53 ... Control command value calculation means, 54 ... Irradiation nozzle control device, 55 ... Treatment table control device, 63 ... Judgment means, 64 ... Irradiation control device .

Claims (8)

  In a radiotherapy apparatus comprising a treatment table on which a patient is placed, an irradiation nozzle that irradiates the patient with radiation, and an image acquisition apparatus that captures an image including the affected area of the patient, the image acquisition apparatus includes a radiation source and the radiation And at least two pairs of detectors for detecting a photographed image by radiation emitted from a source, and the irradiation nozzle has an index portion that can be reflected in an image photographed by the image acquisition device. A radiotherapy apparatus comprising control means for driving and positioning the irradiation nozzle and the treatment table using an image.   The radiotherapy apparatus according to claim 1, wherein the image apparatus is capable of photographing simultaneously from two different directions.   The radiotherapy apparatus according to claim 1, further comprising a moving mechanism that allows the index unit to move relative to the irradiation nozzle.   The means for detecting contact with a patient in the indicator part and a mechanism for enabling the indicator part to move relative to the irradiation nozzle based on the output of the contact detector means are provided. The radiotherapy apparatus according to 1.   The radiotherapy apparatus according to claim 1, wherein the image acquisition apparatus is capable of acquiring on the same image a reference that can identify the index part and the affected part or the affected part position.   Based on the image captured by the image acquisition device, a reference relative position capable of specifying the radiation direction of the therapeutic radiation and the affected part or the affected part position is obtained, and the treatment table on which the patient is placed and the irradiation nozzle are determined based on the relative position. 6. The radiotherapy apparatus according to claim 5, further comprising means for calculating a target position and a target posture.   The radiotherapy according to claim 1, further comprising means for calculating a position of the index portion from an image of the index portion taken by the image acquisition device and positioning an irradiation position of the irradiation nozzle on the affected area. apparatus. The radiotherapy apparatus according to claim 1, further comprising: a unit that determines whether or not the therapeutic radiation can be irradiated based on an image of the index portion captured by the image acquisition apparatus.

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