Absorbed Radiation Dose in Radiosensitive Organs During Coronary CT Angiography Using 320-MDCT: Effect of Maximum Tube Voltage and Heart Rate Variations
Absorbed Radiation Dose in Radiosensitive Organs During Coronary CT Angiography Using 320-MDCT: Effect of Maximum Tube Voltage and Heart Rate Variations
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DOI：
10.2214/ajr.10.4333
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发表时间：
2010-12-01
影响因子：
5
通讯作者：
Clouse, Melvin E.
中科院分区：
文献类型：
--
作者：
Nikolic, Boris;Khosa, Faisal;Clouse, Melvin E.
目标。本文的目的是估算320-MDCT冠状动脉成像中敏感器官的辐射吸收剂量，并确定导管电压变化和心率控制对吸收辐射剂量的影响。使用半导体场效应晶体管探测器测量了100、120和135kVp的拟人体模在扫描视场320 mm、400 mA、320 x 0.5 mm和160 mm准直器宽度(160 mm范围)下60和75次/分钟(Bpm)两种不同频率下甲状腺、乳房、乳房和中肺的吸收辐射剂量。结果在60次/分时，100、120和135kVP的吸收剂量分别为13.41±3.59、21.7±-4.12和29.28±5.17mGy.乳房分别为11.76±0.58、18.86+/-1.06和24.82±1.45mGy.肺分别为12.19+/-2.59、19.09+/-3.12、26.48+/-5.0mGy.甲状腺分别为0.37+/-0.14、0.69+/-0.14、0.92+/-0.2mGy.相应的75次/分吸收剂量分别为：乳房38.34±2.02、59.72±3.13、77.8±3.67 mGy.乳房26.2±1.74、44+/-1.11、52.84+/-4.07mGy.肺部38.02+/-1.58、58.89+/-1.68、78+/-2.93 mGy.甲状腺为0.79+/-0.233、1.04+/-0.18和2.24+/-0.52mGy.在所有管电压设置下，在75到60次/分的心率控制下，管电压降低和心率控制对所有器官的吸收辐射剂量变化都是显著的(p<；0.05)。钙化评分方案的辐射吸收剂量分别为：乳房11.2+/-1.4mGY，乳房9.12+/-0.48mGY，肺脏10.36+/-1.3mGY，甲状腺0.4+/-0.05mGY。结论320-MDCT CT血管成像结果显示，放射敏感器官的吸收剂量与文献报道相当。通过降低管子电压和控制心率，可以显著降低剂量。
OBJECTIVE. The purpose of this article is to estimate the absorbed radiation dose in radiosensitive organs during coronary MDCT angiography using 320-MDCT and to determine the effects of tube voltage variation and heart rate (HR) control on absorbed radiation dose.MATERIALS AND METHODS. Semiconductor field effect transistor detectors were used to measure absorbed radiation doses for the thyroid, midbreast, breast, and midlung in an anthropomorphic phantom at 100, 120, and 135 kVp at two different HRs of 60 and 75 beats per minute (bpm) with a scan field of view of 320 mm, 400 mA, 320 x 0.5 mm detectors, and 160 mm collimator width (160 mm range). The paired Student's t test was used for data evaluation.RESULTS. At 60 bpm, absorbed radiation doses for 100, 120, and 135 kVp were 13.41 +/- 3.59, 21.7 +/- 4.12, and 29.28 +/- 5.17 mGy, respectively, for midbreast; 11.76 +/- 0.58, 18.86 +/- 1.06, and 24.82 +/- 1.45 mGy, respectively, for breast; 12.19 +/- 2.59, 19.09 +/- 3.12, and 26.48 +/- 5.0 mGy, respectively, for lung; and 0.37 +/- 0.14, 0.69 +/- 0.14, and 0.92 +/- 0.2 mGy, respectively, for thyroid. Corresponding absorbed radiation doses for 75 bpm were 38.34 +/- 2.02, 59.72 +/- 3.13, and 77.8 +/- 3.67 mGy for midbreast; 26.2 +/- 1.74, 44 +/- 1.11, and 52.84 +/- 4.07 mGy for breast; 38.02 +/- 1.58, 58.89 +/- 1.68, and 78 +/- 2.93 mGy for lung; and 0.79 +/- 0.233, 1.04 +/- 0.18, and 2.24 +/- 0.52 mGy for thyroid. Absorbed radiation dose changes were significant for all organs for both tube voltage reductions as well as for HR control from 75 to 60 bpm at all tube voltage settings (p < 0.05). The absorbed radiation doses for the calcium score protocol were 11.2 +/- 1.4 mGy for midbreast, 9.12 +/- 0.48 mGy for breast, 10.36 +/- 1.3 mGy for lung, and 0.4 +/- 0.05 mGy for thyroid.CONCLUSION. CT angiography with 320-MDCT scanners results in absorbed radiation doses in radiosensitive organs that compare favorably to those previously reported. Significant dose reductions can be achieved by tube voltage reductions and HR control.