Department of Medical Physics, Medical School, University of Crete, P.O. Box 2208, Heraklion, 71003, Crete, Greece.
Medical Diagnostic Center 'Ayios Therissos', P.O. Box 28405, 2033, Nicosia, Cyprus.
Eur Radiol. 2018 Oct;28(10):4370-4378. doi: 10.1007/s00330-018-5373-7. Epub 2018 Apr 12.
To estimate (a) organ doses and organ-specific radiation-induced cancer risk from a single low-dose CT (LDCT) for lung cancer screening (LCS) and (b) the theoretical cumulative risk of radiation-induced cancer for a typical cohort to be subjected to repeated annual LCS LDCT.
Sex- and body size-specific organ dose data from scan projection radiography (SPR) and helical CT exposures involved in LCS 256-slice LDCT were determined using Monte Carlo methods. Theoretical life attributable risk (LAR) of radiogenic cancer from a single 256-slice chest LDCT at age 55-80 years and the cumulative LAR of cancer from repeated annual LDCT studies up to age 80 years were estimated and compared to corresponding nominal lifetime intrinsic risks (LIRs) of being diagnosed with cancer.
The effective dose from LCS 256-slice LDCT was estimated to be 0.71 mSv. SPR was found to contribute 6-12 % to the total effective dose from chest LDCT. The radiation-cancer LAR from a single LDCT study was found to increase the nominal LIR of cancer in average-size 55-year-old males and females by 0.008 % and 0.018 %, respectively. Cumulative radiogenic risk of cancer from repeated annual scans from the age of 55-80 years was found to increase the nominal LIR of cancer by 0.13 % in males and 0.30 % in females.
Modern scanners may offer sub-millisievert LCS LDCT. Cumulative radiation risk from repeated annual 256-slice LDCT LCS examinations was found to minimally aggravate the lifetime intrinsic cancer risk of a typical screening population.
• Effective dose from lung cancer screening low-dose CT may be <1 mSv. • Screening with modern low-dose CT minimally aggravates lifetime cancer induction intrinsic risk. • Dosimetry of lung cancer screening low-dose CT should encounter the radiation burden from the localizing scan projection radiography. • DLP method may underestimate effective dose from low-dose chest CT by 27 %.
（a）估计单次低剂量 CT（LDCT）用于肺癌筛查（LCS）的器官剂量和特定器官的辐射致癌风险，（b）对于接受重复年度 LCS LDCT 的典型队列，估计辐射致癌的理论累积风险。
使用蒙特卡罗方法确定涉及 LCS 256 层 LDCT 的扫描投影放射摄影术（SPR）和螺旋 CT 暴露的性别和体型特异性器官剂量数据。估计 55-80 岁时单次 256 层胸部 LDCT 的放射性致癌的理论生命归因风险（LAR），以及到 80 岁时重复年度 LDCT 研究的累积 LAR，并与癌症诊断的相应名义终生固有风险（LIR）进行比较。
LCS 256 层 LDCT 的有效剂量估计为 0.71 mSv。发现 SPR 对胸部 LDCT 的总有效剂量贡献了 6-12%。单次 LDCT 研究的辐射致癌 LAR 发现，在平均体型的 55 岁男性和女性中，分别将癌症的名义 LIR 增加了 0.008%和 0.018%。从 55-80 岁年龄开始，重复年度扫描的累积致癌风险发现，在男性中，癌症的名义 LIR 增加了 0.13%，在女性中增加了 0.30%。
现代扫描仪可能提供亚毫西弗的 LCS LDCT。从重复年度 256 层 LDCT LCS 检查的累积辐射风险发现，对典型筛查人群的终生固有癌症风险的恶化最小。
（a）肺癌筛查低剂量 CT 的有效剂量可能<1 mSv。（b）使用现代低剂量 CT 筛查最小化了终生癌症诱导固有风险的恶化。（c）肺癌筛查低剂量 CT 的剂量学应考虑到定位扫描投影放射摄影术的辐射负担。（d）DLP 方法可能低估低剂量胸部 CT 的有效剂量 27%。
