Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen, Germany.
Eur J Radiol. 2012 Feb;81(2):e153-7. doi: 10.1016/j.ejrad.2011.01.052. Epub 2011 Feb 17.
To estimate the effective dose of cardiac CT with different dose saving strategies dependent on varying heart rates.
For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a rotation time of 0.30s and standard protocols with 120 kV and 160 mAs/rot. Protocols were evaluated without ECG-pulsing, with two different ECG-pulsing techniques, and automated exposure control with a simulated heart rate of 60 and 100 beats per minute.
Depending on different dose saving techniques and heart rate, the effective whole-body dose of a cardiac scan ranged from 2.8 to 9.5 mSv and from 4.3 to 16.0 mSv for males and females, respectively. The radiation-sensitive breast tissue in the primary scan range results in an increased female dose of 66.7 ± 6.0%. Prospective triggering has the greatest potential to reduce the effective dose to 27.8%, compared to a comparable scan protocol with retrospective ECG-triggering with no ECG-pulsing. Furthermore, the heart rate influences the radiation exposure by increasing significantly at lower heart rates.
Due to this broad variability in radiation exposure of a cardiac CT, the radiologist and the CT technician should be aware of the different dose reduction strategies.
根据不同的心率，评估不同心脏 CT 剂量节省策略的有效剂量。
使用配备有热释光剂量计的 Alderson-Rando 体模进行剂量测量。根据 ICRP 103 计算有效剂量。使用提供 0.30s 旋转时间和 120kV 及 160mAs/转标准协议的 128 层单源扫描仪进行曝光。评估协议时，分别不使用心电图触发、两种不同的心电图触发技术以及模拟心率为 60 和 100 次/分的自动曝光控制。
根据不同的剂量节省技术和心率，男性和女性的心脏扫描全身有效剂量分别在 2.8 至 9.5mSv 和 4.3 至 16.0mSv 之间。在原始扫描范围内，辐射敏感的乳腺组织会导致女性剂量增加 66.7±6.0%。与具有无心电图触发的回顾性 ECG 触发的可比扫描协议相比，前瞻性触发具有最大的降低有效剂量的潜力，可降低 27.8%。此外，心率越低，辐射暴露的增加越显著。
由于心脏 CT 的辐射暴露存在广泛的可变性，放射科医生和 CT 技师应该了解不同的剂量降低策略。
