| Project/Area Number |
09557066
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Radiation science
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
SHIRATO Hiroki School of Medicine, Hokkaido Univ., Asso.Pro., 医学部, 助教授 (20187537)
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| Co-Investigator(Kenkyū-buntansha) |
KUNIEDA Tatsuya Dev.Trans., Mitsubishi Electronics, co ltd., Chief (Reseacher), 通信機器製作所, 主事 (研究職)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥12,100,000 (Direct Cost: ¥12,100,000)
Fiscal Year 1998: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1997: ¥10,200,000 (Direct Cost: ¥10,200,000)
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| Keywords | Pattern recognition / Radiotherapy / Stereotactic irradiation / Tumor tracking / 動物体追跡 / X線 / 癌治療 |
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| Research Abstract |
Organ motion and setup error have been the largest obstacles in external radiotherapy using the linear accelerator (linac). We have developed a real-time tumor tracking radiotherapy (RTRT) system in which the location of a moving tumor can be detected every 0.03 seconds with an accuracy of *1mm, and the tumor is irradiated only when its location corresponds to the planned position. In preparation, a round gold marker with a diameter of 2.0 mm is inserted in or near the tumor. The coordinates of the tumor center and the gold marker are all transferred from computed tomography to the RTRT.Two sets of diagnostic x-ray fluoroscopy are available in the linac room for detection of the gold marker in the body during radiotherapy. Real-time pattern recognition technology is used for automatic recognition of the projected figure of the gold marker in the fluoroscopic images. The three-dimensional position of the marker is calculated from the two fluoroscopic images every 0.03 seconds. A linear accelerator is synchronized to irradiate the tumor only when the gold marker is located in the planned position. The period between recognition and irradiation is 0.03 seconds. The discrepancy between planned and actual irradiation spot is less than 1.0 mm up to the marker speed of 40 mm/sec. For 10 patients with body tumors in various locations, the marker was inserted into or near the tumor. Treatment time was less than 15 minutes for one session. No complications or local relapses were observed with a median follow-up of 6 months. The real-time tumor tracking system can improve the accuracy of current external radiotherapy for body tumors dramatically, and increase : the potential of radiotherapy by reducing the volume of normal tissue irradiated.
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