Radiation Control Directorate, Tanzania Atomic Energy Commission, P O Box 743 Arusha, Tanzania.
Department of Physics, University of Dar es Salaam, P O Box 35063 Dar es Salaam, Tanzania.
Radiat Prot Dosimetry. 2021 Dec 17;197(2):63-77. doi: 10.1093/rpd/ncab159.
The aim of the present study was to estimate the volume CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED) to patients from five multi-detector computed tomography angiography (MDCTA) procedures: brain, carotid, coronary, entire aorta and lower limb from four medical institutions in Tanzania; to compare these doses to those reported in the literature, and to compare the data obtained with ICRP 103 and Monte Carlo software. The radiation doses for 217 patients were estimated using patient demographics, patient-related exposure parameters, the geometry of examination and CT-Expo V 2.4 Monte Carlo-based software. The median values of the CTDIvol, DLP and ED for MDCTA procedures of the brain and carotids were 36.8 mGy, 1481.0 mGy∙cm and 5.2 mSv, and 15.9 mGy, 1224.0 mGy∙cm and 7.8 mSv, respectively; while for the coronary, entire aortic, and lower limbs were 49.4 mGy, 1493.0 mGy∙cm and 30.6 mSv; 16.2 mGy, 2287.0 mGy∙cm and 41.1 mSv; and 6.4 mGy, 1406.0 mGy∙cm and 10.5 mSv, respectively. The ratio of the maximum to minimum ED values to individual patients across the four medical centers were 41.4, 11.1, 4.6, 9.5 and 37.4, respectively, for the brain, carotid, coronary, entire aortic and lower limb CT angiography procedures. The mean values of CTDIvol, DLP and ED in the present study were typically higher than the values reported from Kenya, Korea and Saudi Arabia. The 75th percentile values of the DLP were above the preliminary diagnostic references levels proposed by Kenya, Switzerland and Korea. The observed wide range of examination scanning protocols and patient doses for similar MDCTA procedures within and across hospitals; and the observed relatively high patient doses compared to those reported in the literature, call for the need to standardize scanning protocols and optimise patient dose from MDCTA procedures.
本研究旨在估算来自坦桑尼亚四家医疗机构的五项多探测器 CT 血管造影 (MDCTA) 程序（脑、颈动脉、冠状动脉、整个主动脉和下肢）的患者 CT 剂量指数 (CTDIvol)、剂量长度乘积 (DLP) 和有效剂量 (ED)；将这些剂量与文献中报道的剂量进行比较，并将所得数据与 ICRP 103 和 Monte Carlo 软件进行比较。使用患者人口统计学、患者相关暴露参数、检查的几何形状和基于 CT-Expo V 2.4 Monte Carlo 的软件，估算了 217 名患者的辐射剂量。脑和颈动脉 MDCTA 程序的 CTDIvol、DLP 和 ED 的中位数值分别为 36.8 mGy、1481.0 mGy·cm 和 5.2 mSv，15.9 mGy、1224.0 mGy·cm 和 7.8 mSv；而冠状动脉、整个主动脉和下肢分别为 49.4 mGy、1493.0 mGy·cm 和 30.6 mSv；16.2 mGy、2287.0 mGy·cm 和 41.1 mSv；6.4 mGy、1406.0 mGy·cm 和 10.5 mSv。四个医疗中心的个体患者中，ED 值的最大值与最小值之比分别为脑、颈动脉、冠状动脉、整个主动脉和下肢 CT 血管造影程序的 41.4、11.1、4.6、9.5 和 37.4。本研究中的 CTDIvol、DLP 和 ED 的平均值通常高于肯尼亚、韩国和沙特阿拉伯报道的值。肯尼亚、瑞士和韩国提出的初步诊断参考水平之上的 DLP 第 75 百分位值。在医院内和跨医院进行类似的 MDCTA 程序时，观察到检查扫描方案和患者剂量的广泛范围；与文献报道的剂量相比，观察到相对较高的患者剂量，因此需要标准化扫描方案并优化 MDCTA 程序的患者剂量。
