Charite Universitatsmedizin Berlin.
University of Helsinki.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2022 Aug;134(2):245-253. doi: 10.1016/j.oooo.2022.03.002. Epub 2022 Mar 12.
The purpose of this study was to evaluate the impact of thyroid gland shielding on radiation doses in dental cone beam computed tomography (CBCT) with small and medium fields of view (FOVs).
Six CBCT protocols were investigated by exposing an adult anthropomorphic male phantom head without and with thyroid shielding, using 4 small (4 × 5 cm) and 2 medium (10 × 6 cm) FOVs. Twenty metal oxide semiconductor field-effect transistor dosimeters were placed in the phantom head to measure absorbed doses and calculate equivalent doses at 11 sites. Effective doses were calculated based on the tissue weighting factors in International Commission on Radiological Protection Publication 103. The data were analyzed using the independent samples t test.
Thyroid gland shielding led to significant equivalent dose reductions in many tissues for all protocols. Equivalent dose reductions to the thyroid were significant in all 6 protocols (P ≤ .037). Significant reduction depended on the FOV and ranged between 24.5% and 42.6% for the thyroid gland and 4.9% and 34.5% for other tissues and organs. Effective doses were significantly lower in all protocols (P ≤ .016).
Thyroid gland shielding protects the thyroid gland and other organs and should be utilized with all CBCT examinations where feasible.
本研究旨在评估小视野和中视野口腔锥形束计算机断层扫描（CBCT）中甲状腺屏蔽对辐射剂量的影响。
通过对无甲状腺屏蔽和有甲状腺屏蔽的成人男性头颅模型进行 4 种小视野（4×5cm）和 2 种中视野（10×6cm）的 6 种 CBCT 扫描方案，暴露于 6 种 CBCT 扫描方案中。在头颅模型内放置 20 个金属氧化物半导体场效应晶体管剂量计，以测量吸收剂量，并计算 11 个部位的当量剂量。有效剂量基于国际辐射防护委员会第 103 号出版物中的组织权重因子进行计算。使用独立样本 t 检验对数据进行分析。
对于所有方案，甲状腺屏蔽导致许多组织的当量剂量显著降低。对于所有 6 种方案，甲状腺的当量剂量降低均具有统计学意义（P≤0.037）。降低的程度取决于视野，范围为 24.5%至 42.6%（对于甲状腺）和 4.9%至 34.5%（对于其他组织和器官）。所有方案的有效剂量均显著降低（P≤0.016）。
甲状腺屏蔽可保护甲状腺和其他器官，应在可行的情况下应用于所有 CBCT 检查。
