Takata Takeshi, Kotoku Jun'ichi, Maejima Hideyuki, Kumagai Shinobu, Arai Norikazu, Kobayashi Takenori, Shiraishi Kenshiro, Yamamoto Masayoshi, Kondo Hiroshi, Furui Shigeru
Graduate School of Medical Care and Technology, Teikyo University Hospital, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
Central Radiology Division, Teikyo University Hospital, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8606, Japan.
J Radiat Res. 2018 Mar 1;59(2):233-239. doi: 10.1093/jrr/rrx062.
To minimise the radiation dermatitis related to interventional radiology (IR), rapid and accurate dose estimation has been sought for all procedures. We propose a technique for estimating the patient skin dose rapidly and accurately using Monte Carlo (MC) simulation with a graphical processing unit (GPU, GTX 1080; Nvidia Corp.). The skin dose distribution is simulated based on an individual patient's computed tomography (CT) dataset for fluoroscopic conditions after the CT dataset has been segmented into air, water and bone based on pixel values. The skin is assumed to be one layer at the outer surface of the body. Fluoroscopic conditions are obtained from a log file of a fluoroscopic examination. Estimating the absorbed skin dose distribution requires calibration of the dose simulated by our system. For this purpose, a linear function was used to approximate the relation between the simulated dose and the measured dose using radiophotoluminescence (RPL) glass dosimeters in a water-equivalent phantom. Differences of maximum skin dose between our system and the Particle and Heavy Ion Transport code System (PHITS) were as high as 6.1%. The relative statistical error (2 σ) for the simulated dose obtained using our system was ≤3.5%. Using a GPU, the simulation on the chest CT dataset aiming at the heart was within 3.49 s on average: the GPU is 122 times faster than a CPU (Core i7-7700K; Intel Corp.). Our system (using the GPU, the log file, and the CT dataset) estimated the skin dose more rapidly and more accurately than conventional methods.
为了将与介入放射学（IR）相关的放射性皮炎降至最低，人们一直在寻求针对所有程序进行快速准确的剂量估算。我们提出了一种使用带有图形处理单元（GPU，GTX 1080；英伟达公司）的蒙特卡罗（MC）模拟来快速准确估算患者皮肤剂量的技术。在根据像素值将计算机断层扫描（CT）数据集分割为空气、水和骨骼后，基于个体患者的CT数据集对透视条件下的皮肤剂量分布进行模拟。假定皮肤为身体外表面的一层。透视条件从透视检查的日志文件中获取。估算吸收的皮肤剂量分布需要对我们系统模拟的剂量进行校准。为此，使用线性函数来近似模拟剂量与在水等效体模中使用放射性光致发光（RPL）玻璃剂量计测量的剂量之间的关系。我们的系统与粒子和重离子传输代码系统（PHITS）之间的最大皮肤剂量差异高达6.1%。使用我们的系统获得的模拟剂量的相对统计误差（2σ）≤3.5%。使用GPU，针对心脏的胸部CT数据集模拟平均在3.49秒内完成：GPU比CPU（酷睿i7 - 7700K；英特尔公司）快122倍。我们的系统（使用GPU、日志文件和CT数据集）比传统方法更快速、更准确地估算了皮肤剂量。
