Department of Physics, University of British Columbia Okanagan, Kelowna, Canada.
Medical Imaging Services, Interior Health, Kelowna, Canada.
J Radiol Prot. 2023 Jul 10;43(3). doi: 10.1088/1361-6498/ace194.
Lead protective garments worn by medical staff in the presence of x-rays develop defects over time. This work proposes a novel method of assessing the protective efficacy of the garments as defects develop. The proposed method applies updated radiobiology data from ICRP 103. This work applied the as low as reasonably achievable principle to devise a formula through which a maximum allowed defect area in lead protective garments can be calculated. This formula depends on the cross-sectional areas (A) and ICRP 103 tissue weighting factors (wt) of the most radiosensitive and overlapping organs protected by the garment, the maximum allowed additional effective dose to the garment wearer due to the defects (d), and the unattenuated absorbed dose at the surface of the garment (D). The maximum allowed defect areas are separated into three regions:, and. To be conservative, it was assumed thatD= 50 mGy yr, andd= 0.3 mSv yr. Also conservatively, transmission was assumed to be 0%, as employing a non-zero transmission factor would increase the maximum allowed defect area. Maximum allowed defect areas were as follows: 370 mmfor above the waist, 37 mmfor below the waist, and 279 mmfor the thyroid. These values can be compared to commonly published values which are 670 mmfor an apron, 15 mmover the gonads, and 11-20 mmfor the thyroid. The proposed method for lead protective garment assessment is highly adaptable as values can be adjusted as radiobiology data are updated, and as values such as radiation dose limits vary across jurisdictions. Future works will include collection of data for unattenuated dose to apron (D) as it varies across professions, so that garments may be allowed different defect areas if relegated to individuals of specific professions.
医用射线防护服在使用过程中会随着时间的推移而出现破损。本工作提出了一种评估防护服防护效果随破损发展情况的新方法。该方法应用了 ICRP 103 中的最新放射生物学数据。本工作应用尽可能低的原则，设计了一个公式，可以计算出防护服允许的最大缺陷面积。该公式取决于受防护服保护的最敏感和重叠器官的截面积（A）和 ICRP 103 组织权重因子（wt）、由于缺陷对防护服佩戴者允许的最大额外有效剂量（d）以及防护服表面未经衰减的吸收剂量（D）。允许的最大缺陷面积分为三个区域： ， 和 。为了保守起见，假设 D=50 mGy yr，d=0.3 mSv yr。同样保守地，假设透射率为 0%，因为采用非零透射率会增加允许的最大缺陷面积。允许的最大缺陷面积如下：腰部以上 370mm，腰部以下 37mm，甲状腺 279mm。这些值可以与通常公布的值进行比较，围裙为 670mm，性腺上方为 15mm，甲状腺为 11-20mm。本研究提出的用于评估铅防护服的方法具有高度的适应性，因为可以根据放射生物学数据的更新和辐射剂量限值在不同司法管辖区的变化来调整这些值。未来的工作将包括收集围裙（D）未经衰减剂量的数据，因为它因职业而异，因此如果将防护服分配给特定职业的个人，防护服可能会允许不同的缺陷面积。
