TY - JOUR
T1 - Radiologic assessment of a self-shield with boron-containing water for a compact medical cyclotron.
AU - Horitsugi, Genki
AU - Fujibuchi, Toshioh
AU - Yamaguchi, Ichiro
AU - Eto, Akihisa
AU - Iwamoto, Yasuo
AU - Hashimoto, Hiromi
AU - Hamada, Seiki
AU - Obara, Satoshi
AU - Watanabe, Hiroshi
AU - Hatazawa, Jun
PY - 2012/7
Y1 - 2012/7
N2 - The cyclotron at our hospital has a self-shield of boron-containing water. The amount of induced radioactivity in the boron-containing water shield of a compact medical cyclotron has not yet been reported. In this study, we measured the photon and neutron dose rates outside the self-shield during cyclotron operation. We estimated the induced radioactivities of the boron-containing water used for the self-shield and then measured them. We estimated the activation of concrete outside the self-shield in the cyclotron laboratory. The thermal neutron flux during cyclotron operation was estimated to be 4.72 × 10(2) cm(-2) s(-1), and the activation of concrete in a cyclotron laboratory was about three orders of magnitude lower than the clearance level of RS-G-1.7 (IAEA). The activity concentration of the boron-containing water did not exceed the concentration limit for radioactive isotopes in drainage in Japan and the exemption level for Basic Safety Standards. Consequently, the boron-containing water is treatable as non-radioactive waste. Neutrons were effectively shielded by the self-shield during cyclotron operation.
AB - The cyclotron at our hospital has a self-shield of boron-containing water. The amount of induced radioactivity in the boron-containing water shield of a compact medical cyclotron has not yet been reported. In this study, we measured the photon and neutron dose rates outside the self-shield during cyclotron operation. We estimated the induced radioactivities of the boron-containing water used for the self-shield and then measured them. We estimated the activation of concrete outside the self-shield in the cyclotron laboratory. The thermal neutron flux during cyclotron operation was estimated to be 4.72 × 10(2) cm(-2) s(-1), and the activation of concrete in a cyclotron laboratory was about three orders of magnitude lower than the clearance level of RS-G-1.7 (IAEA). The activity concentration of the boron-containing water did not exceed the concentration limit for radioactive isotopes in drainage in Japan and the exemption level for Basic Safety Standards. Consequently, the boron-containing water is treatable as non-radioactive waste. Neutrons were effectively shielded by the self-shield during cyclotron operation.
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U2 - 10.1007/s12194-012-0147-4
DO - 10.1007/s12194-012-0147-4
M3 - Article
C2 - 22370731
AN - SCOPUS:85028104554
VL - 5
SP - 129
EP - 137
JO - Radiological Physics and Technology
JF - Radiological Physics and Technology
SN - 1865-0333
IS - 2
ER -