Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.
AJR Am J Roentgenol. 2011 Jul;197(1):W97-103. doi: 10.2214/AJR.10.5057.
The purpose of this study was to determine typical radiation dose levels to patients undergoing CT-guided interventional procedures.
A total of 571 patients undergoing CT interventional procedures were included in this retrospective data analysis study. Enrolled patients underwent one of five procedures: cryoablation, aspiration, biopsy, drain, or injection. With each procedure, two scan modes were used, either intermittent (no table increment) or helical mode. Skin dose was estimated from the volumetric CT dose index (CTDI(vol)) and phantom measurements. Effective dose was calculated by multiplying dose-length product (DLP) and conversion factor (k factor) for helical mode, and using Monte Carlo organ dose coefficients for intermittent mode.
The mean (± SD) skin doses were 728 ± 382, 130 ± 104, 128 ± 81, 152 ± 105, and 195 ± 147 mGy, and the mean effective doses were 119.7 ± 50.3, 20.1 ± 11.0, 13.8 ± 9.2, 25.3 ± 15.4, and 9.1 ± 5.5 mSv for each of the five procedures, respectively. The maximum skin dose was 1.95 Gy. The mean effective dose across all procedure types was 24.1 mSv, with 2.3 mSv from intermittent scans and 21.8 mSv from helical scans.
Substantial dose differences were observed among the five procedures. The risk of deterministic effects appears to be very low, because the maximum observed skin dose did not exceed the threshold for transient skin erythema (2 Gy). The average risk of stochastic effects was comparable to that of 1-10 abdomen and pelvis CT examinations. Although the intermittent mode can contribute substantially to skin dose, it contributes minimally to the effective dose because of the much shorter scan range used.
本研究旨在确定接受 CT 引导介入性操作的患者的典型辐射剂量水平。
本回顾性数据分析研究共纳入 571 例接受 CT 介入性操作的患者。入组患者接受了以下五种操作之一：冷冻消融术、抽吸术、活检术、引流术或注射术。对于每种操作，使用两种扫描模式，即间断式（无床进）或螺旋式。皮肤剂量通过体层 CT 剂量指数（CTDI(vol)）和体模测量来估算。有效剂量通过将剂量长度乘积（DLP）与螺旋式的转换系数（k 因子）相乘，并使用间断式的蒙特卡罗器官剂量系数来计算。
五种操作的平均（±标准差）皮肤剂量分别为 728±382、130±104、128±81、152±105 和 195±147 mGy，平均有效剂量分别为 119.7±50.3、20.1±11.0、13.8±9.2、25.3±15.4 和 9.1±5.5 mSv。最大皮肤剂量为 1.95 Gy。所有操作类型的平均有效剂量为 24.1 mSv，其中 2.3 mSv 来自间断式扫描，21.8 mSv 来自螺旋式扫描。
五种操作之间存在显著的剂量差异。确定性效应的风险似乎很低，因为观察到的最大皮肤剂量未超过瞬态皮肤红斑（2 Gy）的阈值。随机效应的平均风险与 1-10 次腹部和骨盆 CT 检查相当。尽管间断式扫描可以显著增加皮肤剂量，但由于使用的扫描范围较短，对有效剂量的贡献很小。
