Okuhata Katsuya, Monzen Hajime, Nakamura Yasunori, Takai Go, Nagano Keiji, Nakamura Kenji, Kubo Kazuki, Hosono Makoto
Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan.
Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan.
Ann Nucl Med. 2023 Nov;37(11):629-634. doi: 10.1007/s12149-023-01860-x. Epub 2023 Aug 19.
The purpose of this study is to determine the dose reduction of different shielding materials at various distances from a Lu photon radiation source.
Two protective aprons with lead equivalent thicknesses of 0.25 mm and 0.35 mm and tungsten-containing rubber (TCR) were used as shielding materials. A vial containing Lu was sealed in a lead container so that a narrow beam went out through a 3 mm-diameter hole. The dose rate was measured at distances of 0, 10, 50, 100, and 200 cm from the source using a NaI scintillation survey meter to obtain the rate of dose reduction. TCR was tested with thicknesses ranging from 0.3 to 1.0 mm at 0.1 mm intervals and from 1.0 to 4.0 mm at 0.5 mm intervals.
At distances of 0, 10, 50, 100, and 200 cm, the dose reduction for the lead equivalent thickness of 0.25 mm were 32.7%, 54.5%, 93.1%, 97.9%, and 99.6%, respectively; and for the lead equivalent thickness of 0.35 mm were 53.4%, 70.6%, 95.6%, 98.9%, and 99.6%, respectively. Without any shielding, the dose rate decreased by 34.4% at 10 cm and by 88.8% at 50 cm from the radiation source. The dose reduction for the TCR thickness of 3.5 mm was 89.8% at 0 cm and 93.3% at 10 cm. The TCR thickness of 0.4 mm provided a dose reduction comparable to or greater than that of the 0.25 mm lead equivalent, whereas the TCR thickness of 1.0 mm or greater provided a dose reduction comparable to that of the 0.35 mm lead equivalent.
Achieving a reduction of 95% or more requires the 0.25 mm lead equivalent for a distance of 100 cm, the 0.35 mm lead equivalent for 50 cm, the TCR thickness of 0.3 mm for 100 cm, or the TCR thickness of 0.9 mm for 50 cm. Without wearing a protective apron, a reduction of approximately 95% is observed at distances greater than 100 cm. These findings would be useful for medical staff engaging in related activities.
本研究的目的是确定在距镥光子辐射源不同距离处不同屏蔽材料的剂量减少情况。
使用两种铅当量厚度分别为0.25毫米和0.35毫米的防护围裙以及含钨橡胶（TCR）作为屏蔽材料。将一个装有镥的小瓶密封在铅容器中，使窄束光通过一个直径3毫米的孔射出。使用碘化钠闪烁探测仪在距源0、10、50、100和200厘米的距离处测量剂量率，以获得剂量减少率。对TCR进行测试，其厚度范围为0.3至1.0毫米，间隔为0.1毫米；以及1.0至4.0毫米，间隔为0.5毫米。
在0、10、50、100和200厘米的距离处，铅当量厚度为0.25毫米的防护围裙的剂量减少率分别为32.7%、54.5%、93.1%、97.9%和99.6%；铅当量厚度为0.35毫米的防护围裙的剂量减少率分别为53.4%、70.6%、95.6%、98.9%和99.6%。在没有任何屏蔽的情况下，距辐射源10厘米处剂量率降低34.4%，50厘米处降低88.8%。TCR厚度为3.5毫米时，在0厘米处剂量减少率为89.8%，在10厘米处为93.3%。TCR厚度为0.4毫米时提供的剂量减少与0.25毫米铅当量相当或更大，而TCR厚度为1.0毫米或更大时提供的剂量减少与0.35毫米铅当量相当。
要实现95%或更高的剂量减少，在100厘米距离处需要0.25毫米铅当量，50厘米距离处需要0.35毫米铅当量，100厘米距离处需要0.3毫米的TCR厚度，或50厘米距离处需要0.9毫米的TCR厚度。不穿戴防护围裙时，在大于100厘米的距离处可观察到约95%的剂量减少。这些发现对从事相关活动的医务人员将是有用的。
