Yanagi Yuya, Tamura Mikoto, Monzen Hajime, Matsumoto Kenji, Takei Yoshiki, Noma Kazuo, Kida Tetsuo
Department of Radiology, Shiga University of Medical Science Hospital.
Department of Medical Physics, Graduate School of Medical Sciences, Kindai University.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2021;77(2):145-152. doi: 10.6009/jjrt.2021_JSRT_77.2.145.
This study investigated whether real-time variable shape tungsten rubber (STR) could be applied for nail radiation protection in total skin electron beam (TSEB) therapy.
Simulated finger phantoms were made from syringes filled with physiological saline of volumes 5, 10, 20, and 30 ml (inner diameters of 14.1, 17.0, 21.7, and 25.3 mm, respectively). Gafchromic film was applied to the phantom, and lead (thickness 1-3 mm) or STR (thickness 1-4 mm) with an area of 4´1.5 cm was used to cover the film. A 6 MeV electron beam with an 8 mm acrylic board was then used to irradiate the phantom. The source-surface distance (SSD) was 444 cm, the field size was 36´36 cm at SSD of 100 cm without an electron applicator, and the monitor unit was 2000 MU. The shielding rates were obtained from the dose profiles.
The mean values of the shielding rate values for all phantoms were 50.1, 97.6, and 98.7% for 1, 2, and 3 mm of lead, respectively, and -13.6, 53.9, 91.2, and 99.4% for 1, 2, 3, and 4 mm of STR, respectively.
STR with a thickness of 4 mm had the same shielding properties as lead with a thickness of 3 mm, which was an approximately 100% shielding rate. STR could therefore be used in TSEB therapy instead of lead.
本研究调查了实时可变形状钨橡胶（STR）是否可用于全身皮肤电子束（TSEB）治疗中的指甲辐射防护。
用装有5、10、20和30毫升生理盐水（内径分别为14.1、17.0、21.7和25.3毫米）的注射器制作模拟手指模型。将Gafchromic薄膜贴在模型上，并用面积为4×1.5厘米的铅（厚度1 - 3毫米）或STR（厚度1 - 4毫米）覆盖薄膜。然后使用带有8毫米丙烯酸板的6兆电子伏电子束照射模型。源皮距（SSD）为444厘米，在无电子限光筒且SSD为100厘米时射野大小为36×36厘米，监测单位为2000 MU。从剂量分布中获得屏蔽率。
对于所有模型，1、2和3毫米铅的屏蔽率平均值分别为50.1%、97.6%和98.7%，1、2、3和4毫米STR的屏蔽率平均值分别为 - 13.6%、53.9%、91.2%和99.4%。
厚度为4毫米的STR具有与厚度为3毫米的铅相同的屏蔽性能，屏蔽率约为100%。因此，STR可用于TSEB治疗以替代铅。
