1 Department of Radiology, Rush University Medical Center, 1653 W Congress Pkwy, Chicago, IL 60612.
2 Department of Abdominal and Interventional Imaging, Massachusetts General Hospital, Boston, MA.
AJR Am J Roentgenol. 2018 Mar;210(3):657-662. doi: 10.2214/AJR.17.17952. Epub 2018 Jan 11.
This study assessed radiation dose after CT-guided percutaneous radiofrequency ablations (RFAs) of hepatic and renal tumors and the effect of weight-based CT protocol modification for lowering overall dose in these procedures.
CT-guided RFA for renal and hepatic ablations performed from January 1, 2009, through December 31, 2009, were retrospectively reviewed (90 men and 48 women; age, 42-81 years). The radiation dose was recorded during each of the following steps: planning, performing, and postprocedure. Weight-based protocol modification changes in tube voltage and tube current were then applied to renal and hepatic ablations performed subsequently (18 men and 11 women; age, 48-82 years). Image quality, needle localization, lesion detection, ability to detect complications, and overall operator satisfaction were noted for each case (score, 1-5). Dose reduction after modification was then calculated.
Retrospective analysis found a mean (± SD) overall CT dose index (CTDI) for CT-guided RFA to be 16.5 ± 2.3 mGy. After protocol modification, the mean CTDI decreased to 6.63 ± 0.67 mGy, a 59.6% reduction overall; for hepatic ablations, the reduction was 65.96% (p < 0.0001) and the reduction for renal ablations was 38.97% (p = 0.0153). Image quality analysis showed high operator satisfaction (3-5), including adequate needle localization (4-5), lesion visibility (3-5), and high performer confidence (4-5). Higher dose reduction was noted for patients weighing more than 180 lb (82 kg) (p < 0.0001).
Simple weight-based CT protocol modifications can significantly reduce radiation dose during CT-guided percutaneous ablations in the liver and kidneys without significantly sacrificing image quality.
本研究评估了 CT 引导下经皮射频消融（RFA）治疗肝、肾肿瘤的辐射剂量，并探讨了基于体重的 CT 方案修改对降低这些手术总剂量的影响。
回顾性分析了 2009 年 1 月 1 日至 2009 年 12 月 31 日期间行 CT 引导下 RFA 治疗的肾、肝肿瘤患者（90 例男性，48 例女性；年龄 42-81 岁）。记录了以下各步骤的辐射剂量：计划、执行和术后。随后对行肾、肝 RFA 的患者应用基于体重的方案修改，改变管电压和管电流（18 例男性，11 例女性；年龄 48-82 岁）。记录了每个病例的图像质量、针定位、病灶检测、并发症检测能力和整体操作者满意度（评分 1-5 分）。然后计算修改后的剂量降低。
回顾性分析发现，CT 引导下 RFA 的总体 CT 剂量指数（CTDI）平均值（±标准差）为 16.5±2.3mGy。方案修改后，CTDI 的平均值降低至 6.63±0.67mGy，总降低率为 59.6%；肝 RFA 降低 65.96%（p＜0.0001），肾 RFA 降低 38.97%（p=0.0153）。图像质量分析显示操作者满意度高（3-5 分），包括良好的针定位（4-5 分）、病灶可见性（3-5 分）和操作者信心高（4-5 分）。体重超过 180 磅（82kg）的患者的剂量降低更显著（p＜0.0001）。
简单的基于体重的 CT 方案修改可以显著降低肝、肾 CT 引导下经皮消融术的辐射剂量，而不会显著牺牲图像质量。
