Radiation dose reduction in thoracic and abdomen-pelvic CT using tube current modulation: A phantom study

Abstract

This phantom study was designed to compare the radiation dose in thoracic and abdomen-pelvic CT scans with and without use of tube current modulation (TCM). Effective dose (ED) and size-specific dose estimation (SSDE) were calculated with the absorbed doses measured at selective radiosensitive organs using a thermoluminescence dosimeter-100 (TLD-100). When compared to protocols without TCM, the ED and SSDE were reduced significantly with use of TCM for both the thoracic and abdomen-pelvic CT. With use of TCM, the ED was 6.50 ± 0.29 mSv for thoracic and 6.01 ± 0.20 mSv for the abdomen-pelvic CT protocols. However without use of TCM, the ED was 20.07 ± 0.24 mSv and 17.30 ± 0.41 mSv for the thoracic and abdomen-pelvic CT protocols, respectively. The corresponding SSDE was 10.18 ± 0.48 mGy and 11.96 ± 0.27 mGy for the thoracic and abdomen-pelvic CT protocols with TCM and 31.56 ± 0.43 mGy and 33.23 ± 0.05 mGy, for thoracic and abdomen-pelvic CT protocols without TCM, respectively. The highest absorbed dose was measured at the breast with 8.58 ± 0.12 mGy in the TCM protocols and 51.52 ± 14.72 mGy in the protocols without TCM during thoracic CT. In the abdomen-pelvic CT, the absorbed dose was highest at the skin with 9.30 ± 1.28 mGy and 29.99 ± 2.23 mGy in protocols with and without use of TCM, respectively. In conclusion, the TCM technique results in significant dose reduction, thus it is to be highly recommended in routine thoracic and abdomen-pelvic CT.