Radiation dose to breasts from a cardiac computed tomography angiographyscanogram can be reduced by switching tube position

Abstract

Background/aim: In a computed tomography (CT) examination, scanogram images are used to determine the range of the area to be imaged before scanning. The importance of scanogram image exposure has increased since total examination radiation has decreased due to technological advancements. The purpose of this study was to determine and compare radiation doses delivered to patients while the tube was in anterior-posterior (AP) and posterior-anterior (PA) positions during a CT angiography scanogram. Materials and methods: The radiation doses absorbed by the breast tissue of 55 female patients who underwent cardiac dual-source computed tomography (DSCT) angiography were determined using thermoluminescent dosimeters (TLD-100, Harshaw, MA, USA). Four patients were excluded from the study for various reasons. Results: Radiation doses absorbed by the breasts were significantly lower when the tube position was switched during the scanogram. The absorbed doses, calculated from scanogram exposures, were 520 ± 50 μSv for the AP projection and 410 ± 45 μSv for the PA projection. Total skin doses from the DSCT examinations were 18.9 ± 2.3 mSv. Conclusion: We attributed the approximately 20% lower doses to the position of the scanogram tube, which was in the PA position.