Hwang Yi-Shuan, Tsai Hui-Yu, Lin Yu-Ying, Lui Kar-Wai
Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, 5 Fushing Street, Kweishan, Taoyuan, 333, Taiwan, Republic of China.
Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
BMC Med Imaging. 2018 Feb 5;18(1):2. doi: 10.1186/s12880-018-0247-7.
To investigate the organ dose, effective dose (ED), conversion factor, and the C-arm rotation angle effects on dose variations of abdominal C-arm cone-beam computed tomography (CBCT) during transarterial chemoembolization (TACE).
The organ doses and EDs for abdominal C-arm CBCT were retrospectively calculated according to a Monte Carlo technique for 80 patients. Dose variations from projections, ED to dose-area product (DAP) ratios, and effects of body mass index (BMI) on the ED and ED to DAP ratios were also analyzed.
The kidney received the highest dose (14.6 ± 1.2 mSv). Organ dose deviations among C-arm rotation angles was highest for stomach (CV = 0.71). The mean ED of the the CBCT run during TACE was 3.5 ± 0.5 mSv, and decreased with increased BMI (R = 0.45, p < 0.001). The mean ED to DAP ratio was 0.27 ± 0.04 mSv·Gy·cm and tended to decrease with increased BMI (R = 0.55, p < 0.001). The mean ED to DAP ratios were 0.29 ± 0.02, 0.26 ± 0.02, and 0.23 ± 0.03 mSv·Gy·cm for patients with BMI < 25 kg/m, 25-30 kg/m, and ≥30 kg/m, respectively.
Suitable conversion factors for C-arm CBCT facilitate the use of DAPs for estimating the ED. The patient dose can be varied by adjusting the CBCT rotation angle setting, and dose reduction strategies can be further manipulated.
探讨经动脉化疗栓塞术（TACE）期间腹部C形臂锥形束计算机断层扫描（CBCT）的器官剂量、有效剂量（ED）、转换系数以及C形臂旋转角度对剂量变化的影响。
采用蒙特卡罗技术对80例患者的腹部C形臂CBCT的器官剂量和ED进行回顾性计算。还分析了投影剂量变化、ED与剂量面积乘积（DAP）的比值以及体重指数（BMI）对ED和ED与DAP比值的影响。
肾脏接受的剂量最高（14.6±1.2 mSv）。胃在C形臂旋转角度间的器官剂量偏差最大（变异系数=0.71）。TACE期间CBCT扫描的平均ED为3.5±0.5 mSv，并随BMI增加而降低（R=0.45，p<0.001）。平均ED与DAP比值为0.27±0.04 mSv·Gy·cm，且随BMI增加有降低趋势（R=0.55，p<0.001）。BMI<25 kg/m²、25-30 kg/m²和≥30 kg/m²患者的平均ED与DAP比值分别为0.29±0.02、0.26±0.02和0.23±0.03 mSv·Gy·cm。
C形臂CBCT合适的转换系数有助于使用DAP来估算ED。可通过调整CBCT旋转角度设置改变患者剂量，且可进一步优化剂量降低策略。
