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RADIATION THERAPY APPARATUS

Foreign code F180009567
File No. S2017-0528-C0
Posted date Nov 5, 2018
Country WIPO
International application number 2018JP009499
International publication number WO 2018168766
Date of international filing Mar 12, 2018
Date of international publication Sep 20, 2018
Priority data
  • P2017-047982 (Mar 14, 2017) JP
Title RADIATION THERAPY APPARATUS
Abstract Through the present invention, three-dimensional coordinates of a tracking object moving in an irradiation object can be calculated from fluoroscopic X-ray images captured and acquired from various angles in a single fluoroscopic X-ray device mounted to a radiation therapy apparatus. The three-dimensional coordinates of the tracking object are calculated on a straight tracking object presence line connecting an X-ray generating device for fluoroscopy and the position in an X-ray plane detector of the tracking object on the fluoroscopic X-ray image acquired by the X-ray generating device for fluoroscopy and the X-ray plane detector, and using line segment information included in a movement region of the tracking object set in advance (S104).
Outline of related art and contending technology BACKGROUND ART
Such as a cancer patient to radiation such as X-ray or a charged particle radiation therapy to an affected part is known.This treatment in recent years, more normal tissue to radiation can be suppressed, resulting in localized treating the affected area immediately before the treatment of the patient anatomical information of the location of the affected site and its surrounding tissue in an attempt to accurately grasp the information has been carried out.Immediately before the treatment of the patient's body in order to obtain anatomical information, the radiation treatment device provided in the radiation from the various angles for an affected part with the rotating gantry mounted on the X-ray imaging apparatus using a perspective view of a cone beam CT (CBCT) CBCT imaging apparatus is used.The CBCT imaging apparatus to the patient while rotating the gantry so as to surround the X-ray photographed intermittently perspective, X-ray image acquired by the perspective three-dimensional reconstruction 3 can create a three-dimensional image 3.CBCT image is acquired of the patient treatment plan is compared to the CT image, when a treatment plan and the position of the bone and organ of the affected area and the vicinity thereof are coincident with each other and the determination of whether the patient so as to match the two positions used for alignment.It should be noted that, in the case of the affected area of cancer the patient is being treated is mainly means a tumor.
In the radiation therapy to the patient's body, and the subject is breathing by the tumor may move.In such a case, the entire movement range of the tumor is considered a method of applying radiation to the radiation dose to normal tissue is increased.Normal tissue dose of radiation to the tumor as much as possible can be applied in order to concentrate the radiation, current, the tracked object is previously embedded in the vicinity of the tumor (a metallic marker) is a perspective view from the position in the photographed image in the X-ray is measured, such as X-ray image on the perspective that it tracks the location of the tumor is estimated from the position of the object, the tracked object in a predetermined position only when the phase of the respiration of the tumor is irradiated with radiation to the normal tissue can be reduced by the irradiation method is adopted.Generally the phase of the respiration rate 1 as a feature in which the movement of the breathing cycle phase is reduced and a long residence time in the expiration phase, the above-described radiation treatment when the breathing condition this exhalation phase is irradiated with radiation is employed.Therefore, a radiation treatment plan in the planning CT is used for a treatment plan phase state of the patient's breath by breath produced, captured in a state that the image is being used.
CBCT is captured just prior to the treatment described above is, in the presence of a tumor in the body trunk of the periphery of the bone and organ tumor or breath motion, CBCT image fluctuation is obtained.Moving the image fluctuation and the exact location of a tumor or organ cannot be identified, the treatment planning CT cannot be compared.In order to solve this problem the patient's body to track the movement of infrared markers, movement of the diaphragm or within the X-ray image at the time of shooting on the CBCT a perspective view of the phase of the respiration can be monitored to determine, when a treatment plan at the time of photographing the same respiratory phase X-ray image subtraction using only the three-dimensional reconstruction 3 can reduce the influence caused by the motion blur and the image quality of the acquired CBCT image is a method.CBCT image for obtaining such 4 imaging techniques may be a three-dimensional CBCT (4D-CBCT) imaging technique has been developed in recent years are referred to.However, the above-described motion of the diaphragm and the body motion that may occur out of the correlation has been reported, in the case of the diaphragm at the time of imaging the imaging region on the CBCT X-ray image does not appear in the perspective view in some cases.More, exactly the same as at the patient's treatment plan to know the state of the respiratory phase in the vicinity of the tumor or directly to the motion of the tracked object 3 it is desirable that the three-dimensional tracking.In recent years, as described in Patent Document 1 is a perspective view of the axis perpendicular to the X-ray imaging apparatus 2 with the vicinity of the tumor in the CBCT imaging apparatus tracking the object 3 embedded in track 3 of the three-dimensional CBCT imaging the tumor in three-dimensional position measurement technique has been developed.
Scope of claims (In Japanese)請求の範囲
[請求項1]
 照射対象を支持するためのカウチと、
 カウチの照射対象に対して様々な角度から治療放射線を照射するために照射対象の周囲を移動可能なガントリーと、
 ガントリーに搭載され、照射対象の透視X線画像を取得するための透視用X線発生装置およびX線平面検出器と、
 透視用X線発生装置およびX線平面検出器を用いてコーンビームCT撮影を行い、コーンビームCT画像を取得するCBCT撮影装置と、
 透視X線画像の照射対象内に投影された追跡対象物を2次元追跡する2次元動体追跡装置と、
 を備え、
 各透視X線画像上に投影された追跡対象物の像についての治療室座標系における3次元座標とX線発生装置の3次元座標とを結んで形成する追跡対象物存在直線上であって、予め設定した移動領域に含まれる座標を追跡対象物の3次元座標とする、
 放射線治療装置。
[請求項2]
 請求項1に記載の放射線治療装置であって、
 各透視X線画像上に投影された追跡対象物の像についての治療室座標系における3次元座標とX線発生装置の3次元座標とを結んで形成する追跡対象物存在直線と、予め設定した追跡対象物の移動領域との2つの交点の中点を追跡対象物の3次元座標とする、
 放射線治療装置。
[請求項3]
 照射対象を支持するためのカウチと、
 カウチの照射対象に対して様々な角度から治療放射線を照射するために照射対象の周囲を移動可能なガントリーと、
 ガントリーに搭載され、照射対象の透視X線画像を取得するための透視用X線発生装置およびX線平面検出器と、
 透視用X線発生装置およびX線平面検出器を用いてコーンビームCT撮影を行い、コーンビームCT画像を取得するCBCT撮影装置と、
 透視X線画像の照射対象内に投影された追跡対象物を2次元追跡する2次元動体追跡装置と、
 を備え、
 事前に取得した呼吸位相毎の追跡対象物の位置を含む4次元CT画像上の各追跡対象物の位置を治療室座標系に置き換え、4次元CT画像上の各呼吸位相における追跡対象物の位置間を結んだ位相間移動直線と追跡対象物存在直線との交点または共通垂線をそれぞれ計算し、交点が存在する場合は前記交点を追跡対象物の3次元座標とし、交点が存在しない場合は共通垂線の長さが最も短くなる位相間移動直線上の共通垂線上の点を追跡対象物の3次元座標とする、
 放射線治療装置。
[請求項4]
 照射対象を支持するためのカウチと、
 カウチの照射対象に対して様々な角度から治療放射線を照射するために照射対象の周囲を移動可能なガントリーと、
 ガントリーに搭載され、照射対象の透視X線画像を取得するための透視用X線発生装置およびX線平面検出器と、
 透視用X線発生装置およびX線平面検出器を用いてコーンビームCT撮影を行い、コーンビームCT画像を取得するCBCT撮影装置と、
 透視X線画像の照射対象内に投影された追跡対象物を2次元追跡する2次元動体追跡装置と、
 2対の動体追跡用X線発生装置と動体追跡用X線平面検出器とを含み、取得した透視X線画像上で追跡対象物を3次元追跡する3次元動体追跡装置と、
 を備え、
 コーンビームCT撮影中に取得した透視X線画像上に投影された追跡対象物の像の治療室座標系における3次元座標と、X線発生装置の3次元座標とを結んで形成する追跡対象物存在直線上であって、(i)3次元動体追跡装置により取得した治療室座標系内の追跡対象の3次元移動軌跡上にある点、(ii)3次元移動軌跡と、追跡対象物存在直線とが垂直に交わる共通垂線を算出し、最も共通垂線が短くなる3次元移動軌跡上にある点、(iii)3次元移動軌跡と、追跡対象物存在直線とが垂直に交わる共通垂線を算出し、最も共通垂線が短くなる追跡対象物存在直線上にある点、(iv)共通垂線長の中点、のいずれかを追跡対象の3次元座標とする、
 放射線治療装置。
[請求項5]
 請求項1~4のいずれか1つに記載の放射線治療装置において、
 各透視X線画像について得られた追跡対象物の3次元座標に基づいて、照射対象の呼吸位相を判定し、1つの呼吸位相の透視X線画像を選出し、その呼吸位相の透視X線画像から照射対象の3次元画像を再構成する、
 放射線治療装置。
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • NATIONAL UNIVERSITY CORPORATION HOKKAIDO UNIVERSITY
  • Inventor
  • FUJII Takaaki
  • TAKAO Seishin
  • MIYAMOTO Naoki
  • MATSUURA Taeko
  • UMEGAKI Kikuo
IPC(International Patent Classification)
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