Department of Medical Physics, Faculty of Medicine, University of Crete, Crete, Greece.
Circulation. 2010 Dec 7;122(23):2394-402. doi: 10.1161/CIRCULATIONAHA.109.935346. Epub 2010 Nov 22.
Available data on the radiation burden from coronary computed tomography (CT) angiography (CCTA) are mostly limited to effective dose estimates. This study provides individualized estimates of doses and associated life attributable risks of radiation-induced cancer in a clinical patient population undergoing 256-slice CCTA.
Typical retrospectively and prospectively ECG-gated CCTA exposures in a 256-slice CT scanner were simulated on 52 patient-specific voxelized phantoms. Dose images depicting the dose deposition on the exposed region were generated, and normalized organ doses for all primarily irradiated radiosensitive organs were derived and correlated to patient body habitus. Lung, breast, and esophagus absorbed doses were then determined in 136 consecutive patients subjected to CCTA. Projected life attributable risks of radiation-induced cancer were estimated through the use of appropriate sex-, age- and organ-specific cancer risk factors and compared with corresponding nominal cancer risks. The total projected life attributable risk of radiogenic cancer after CCTA decreases steeply with age at exposure, and lung cancer constitutes the most probable detriment for both sexes. The relative risks of lung cancer associated with prospectively ECG-gated CCTA were 1.0032 and 1.0008 for women and men, respectively. The mean total projected life attributable risks were estimated to be 24.9±7.4 and 71.5±30.0 per 100,000 women undergoing prospectively and retrospectively ECG-gated CCTA, respectively. The corresponding values for men were 7.3±1.3 and 31.4±5.0 per 100 000 patients.
The mean projected life attributable risks of radiation-induced cancer in a typical clinical patient cohort undergoing standard prospectively ECG-gated CCTA with a 256-slice scanner were found to inconsequentially increase the natural cancer incidence rates.
目前关于冠状动脉计算机断层扫描血管造影（CCTA）辐射剂量的资料主要局限于有效剂量估计值。本研究提供了在接受 256 层 CCTA 检查的临床患者人群中，基于个体的辐射致癌剂量和相关归因风险的估计值。
在 256 层 CT 扫描仪上，对 52 个个体化的体素化体模进行了回顾性和前瞻性心电图门控 CCTA 典型曝光模拟。生成了描绘受照区域剂量沉积的剂量图像，并得出了所有主要受照射的敏感器官的归一化器官剂量，并与患者的体型相关联。然后在 136 例接受 CCTA 的连续患者中确定了肺、乳腺和食管的吸收剂量。通过使用适当的性别、年龄和器官特异性癌症风险因素，估算了辐射致癌的预期终生归因风险，并与相应的名义癌症风险进行了比较。CCTA 后，辐射致癌的预期终生归因风险随着受照年龄的增加而急剧下降，肺癌是两性最有可能的危害。前瞻性心电图门控 CCTA 与女性和男性肺癌相关的相对风险分别为 1.0032 和 1.0008。预计前瞻性和回顾性心电图门控 CCTA 后，女性每 100,000 人总预期终生归因风险分别为 24.9±7.4 和 71.5±30.0，男性分别为 7.3±1.3 和 31.4±5.0。
在接受标准前瞻性心电图门控 CCTA 的典型临床患者队列中，256 层 CT 扫描仪的平均预期终生归因辐射致癌风险对自然癌症发生率的影响可忽略不计。
