Tanaka Kenichi, Endo Satoru, Tateoka Kunihiko, Asanuma Osamu, Kamo Ken-Ichi, Sato Kaori, Takeda Hiromitsu, Takagi Masaru, Hareyama Masato, Takada Jun
Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 17, Chuo-ward, Sapporo, Hokkaido 060-8556, Japan.
J Radiat Res. 2014 Jan 1;55(1):162-7. doi: 10.1093/jrr/rrt087. Epub 2013 Jun 30.
The aim of this study is to demonstrate the feasibility of estimating the strength of the moving radiation source during patient implantation. The requirement for the counting time was investigated by comparing the results of the measurements for the static source with those for the source moving at 2, 5, 10 and 20 cm s(-1). The utilized source was (125)I with an air-kerma strength of 0.432 U (μGym(2)h(-1)). The detector utilized was a plastic scintillation detector (8 cm × 5 cm × 2 cm in thickness) set at 8 cm away from the needle to guide the source. Experiments were conducted in order to determine the most desirable counting time. Analysis using the maximum of the measured values while the source passed through the needle indicated that the results for the moving source increased more than those for the static source as the counting time decreased. The combined standard uncertainty, with the coverage factor of 1, was within 4% at the counting time of 100 ms. This investigation supported the feasibility of the method proposed for estimating the source strength during the implantation procedure, regardless of the source speed. The method proposed is a potential option for reducing the risk of accidental replacements of sources with those of incorrect strengths.
本研究的目的是证明在患者植入过程中估算移动辐射源强度的可行性。通过比较静态源与以2、5、10和20 cm s⁻¹速度移动的源的测量结果，研究了计数时间的要求。所使用的源是空气比释动能强度为0.432 U（μGym²h⁻¹）的¹²⁵I。所使用的探测器是一个塑料闪烁探测器（厚度为8 cm×5 cm×2 cm），设置在距针8 cm处，用于引导源。进行实验以确定最理想的计数时间。对源穿过针时测量值的最大值进行分析表明，随着计数时间的减少，移动源的结果比静态源的结果增加得更多。在计数时间为100 ms时，包含因子为1的合成标准不确定度在4%以内。本研究支持了所提出的在植入过程中估算源强度的方法的可行性，而与源的速度无关。所提出的方法是降低用强度不正确的源意外替换源的风险的一个潜在选择。
