Research Project
Grant-in-Aid for Scientific Research (C)
No established method is available for real-time measurements of prescribed dose in the patient body during high-energy X-ray beam irradiation in cancer therapy. We proposed a novel PEV method that utilizes positron production. This research is to realize the method. Here is the summary of the results.(1) High-energy X-rays are photons. The photon can produce a pair of electron and positron. We reached to an idea that the distribution of production points corresponds to the irradiated area, and theoretically studied the idea. The results of simulation calculations with the Geant4 code showed that many number of electron-positron pairs were produced and each of the positrons were combined with electrons in the body to annihilate into to photons in the irradiated area.(2) We found an extremely high background in the radiotherapy room. We managed the circumstance by using the originally fabricated sensors with inorganic scintillation (YAP(Ce)) to form a telescope, and detected annihilation photons successfully.(3) We could measure the size of irradiated area with the position resolution of about 1mm by defining the view of the telescope with collimators.(4) As the result of this research, we conclude that one can carry out real-time monitoring of the irradiated area for dose delivery during X-ray irradiation with the proposed PEV method.Our success obtained in this research in the real-time monitoring of the area is far ahead to the achievements for the purpose even in the scope of the whole world. As a future plan, we recommend to make a PEV camera with one hundred sensors for the clinical use. Real-time processing of the signals from the camera will make possible to show the result on the display for radiation oncologist, and this will avoid unfortunate miss-irradiation.
All 2008 2007 2006 2005
All Journal Article (12 results) (of which Peer Reviewed: 4 results) Presentation (31 results)
Japanese Journal of Medical Physics 27・2
Pages: 50-57
Japanese Journal of Medical Physics 27(2)
医学物理 25・4
Pages: 156-164
10020538457
International Journal of Radiation Oncology Biology Physics 66・3Supp
Japanese Journal of Medical Physics 25(4)
International Journal of Radiation Oncology Biology\Physics 66(3 Supp. )
International Journal of Radiation Oncology Biology. Physics 66・3 Supp
北里医学 35・1
Pages: 38-47
Kitasato Medicine 35(1)
