Department of Medical Physics, University of Crete, Crete, Greece.
Invest Radiol. 2012 Feb;47(2):109-15. doi: 10.1097/RLI.0b013e31822d0cf3.
Risk-benefit analysis of triple-rule-out 256-slice computed tomography angiography (TRO-CTA) requires data on associated cancer risks, currently not available. The aim of the current study was to provide estimates of patient radiation burden and lifetime attributable risk (LAR) of radiation-induced cancer in patients undergoing typical 256-slice TRO-CTA.
Standard step-and-shoot 256-slice TRO-CTA exposures were simulated on 31 male and 31 female individual-specific voxelized phantoms using a Monte Carlo CT dosimetry software. Dose images were generated depicting the dose deposition on the exposed body region of the patient. Organ doses were obtained for all primarily irradiated radiosensitive organs. Organ doses were correlated to patient body size. TRO-CTA effective dose was estimated from (a) organ doses and (b) dose-length product data. Recently published sex-, age-, and organ-specific cancer risk factors were used to estimate the total LAR of radiation-induced cancer. The theoretical risks of radiation-induced cancer to the lung and breast following a 256-slice TRO-CTA were compared with the corresponding nominal risks for each of the studied patients.
The highest organ doses were observed for the breast, heart, esophagus, and lung. Mean effective dose estimated using organ dose data was found to be 6.5 ± 1.0 mSv for female and 3.8 ± 0.7 mSv for male individuals subjected to 256-slice TRO-CTA. The associated mean LARs of cancer was found to be 41 per 10 female and 17 per 10 male patients. The total radiation-induced cancer risk was found to markedly decrease with patient age. TRO-CTA exposure was found to increase the intrinsic risks of developing lung or breast cancer during the remaining lifetime by less than 0.5% and 0.1%, respectively.
The mean theoretical risk of radiation-induced cancer for a patient cohort subjected to step-and-shoot 256-slice TRO-CTA may be considered to be low compared with the intrinsic risk of developing cancer.
三导联检查 256 层计算机断层血管造影术（TRO-CTA）的风险效益分析需要有关癌症风险的数据，目前尚不可用。本研究的目的是提供接受典型 256 层 TRO-CTA 检查的患者的辐射负担和辐射诱发癌症的终生归因风险（LAR）的估计值。
使用蒙特卡罗 CT 剂量测定软件对 31 名男性和 31 名女性个体特定体素化体模进行标准步进式 256 层 TRO-CTA 曝光模拟。生成剂量图像以描绘患者暴露身体区域的剂量沉积。获得所有主要受照射的敏感器官的器官剂量。将器官剂量与患者的体型相关联。TRO-CTA 有效剂量是根据（a）器官剂量和（b）剂量长度乘积数据估算得出的。使用最近发表的基于性别，年龄和器官特异性的癌症风险因素来估算辐射诱发癌症的总 LAR。与每个研究患者的相应名义风险相比，比较了 256 层 TRO-CTA 后肺部和乳房的辐射诱发癌症的理论风险。
观察到的最高器官剂量为乳房，心脏，食道和肺部。使用器官剂量数据估算的平均有效剂量分别为接受 256 层 TRO-CTA 的女性和男性个体的 6.5 ± 1.0 mSv 和 3.8 ± 0.7 mSv。发现的平均癌症 LAR 为每 10 名女性 41 例和每 10 名男性 17 例。发现总辐射诱发癌症的风险随患者年龄的增加而明显降低。发现 TRO-CTA 暴露会使在剩余的有生之年中发展为肺癌或乳腺癌的内在风险分别增加不到 0.5％和 0.1％。
与发展癌症的内在风险相比，接受步进式 256 层 TRO-CTA 的患者队列的平均理论辐射致癌风险可能被认为较低。
