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- M. Muramatsu, S. Hojo, A. Kitagawa
NIRS, Chiba-shi, Japan
- Y. Kijima
Mitsubishi Electric Corp., Energy & Public Infrastructure Systems Center, Kobe, Japan
- H. Miyazaki, K. Sawada, T. Ueno
SHI, Ehime, Japan
- K. Torikai, S. Yamada
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
- M. Tsuchiyama, S. Ueda
Mitsubishi Electric Corp., Energy Systems Centre, Kobe, Japan
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Carbon-ion radiotherapy has been carried out at Gunma University Heavy Ion Medical Centre (GHMC) since March 2010. A compact ECR ion source for GHMC, so-called KeiGM, supplies C4+ ions for treatment. A microwave source with the traveling-wave-tube was adopted for KeiGM, with a frequency range and maximum power of 9.75 - 10.25 GHz and 750 W, respectively. KeiGM was operated from March to May 2010 for the clinical trial without any trouble and maintenance. KeiGM supplied the carbon ions from 7:30 in the morning to 0:00 midnight on weekdays. Sometimes it was operated for the beam tuning of accelerator on Saturday and Sunday too. The operation time of KeiGM for two months was about 780 hours. Although the beam intensity decreased by 20% at first, it has been constant for the last two months. The beam intensity of C4+ was 200 euA at 30 kV extraction in May 2010. The fluctuation of beam intensity was less than 10%. The operation parameters were as follows; the microwave frequency and power were 10.042 GHz and 300 W, respectively. CH4 gas was fed, and the gas flowrate was 0.054 cc/min. The extraction voltage was 30 kV. The repetition frequency and pulse width were 0.36 Hz and 50 msec, respectively. Gunma University has successfully treated the first 12 patients for the clinical trial, thus the Japanese Ministry of Health and Labor Welfare approved GHMC as “advanced medicine”. We will report the operation of KeiGM and the status of their daily treatment.
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