ESTIMATION OF ENTRANCE SURFACE AIR KERMA IN DIGITAL RADIOGRAPHIC EXAMINATIONS.

Abstract

Contribution of radiation doses from medical X-ray examination to collective dose is significant. Unusually, high doses may increase the risk of stochastic effects of radiations. Therefore, radiation dose assessment was performed in 241 digital X-ray examinations in the study and was compared with published dose reference levels (DRLs). Entrance surface air kerma (ESAK) was calculated in chest PA, cervical AP/Lat, abdomen AP, lumbar AP/Lat and pelvis AP digital radiographic examinations (119 male and 122 female) following the International Atomic Energy Agency recommended protocol. Initially, 270 digital examinations were selected, reject analysis was performed and final 241 examinations were enrolled in the study for dose calculations. The exposure parameters and X-ray tube output were used for dose calculations. Effective doses were estimated with the help of conversion coefficients from ICRP 103. Median ESAK (mGy) and associated effective doses obtained were cervical spine AP (1.30mGy, 0.045mSv), cervical spine Lat (0.25mGy, 0.005mSv), chest PA (0.11mGy, 0.014mSv), abdomen AP (0.90mGy, 0.118mSv), lumbar spine AP (1.52mGy, 0.177mSv), lumbar spine Lat (7.76mGy, 0.209mSv) and pelvis AP (0.82mGy, 0.081mSv). Results were compared with the studies of UK, Oman, India and Canada. The calculated ESAK and effective dose values were less than or close to previously published literature except for cervical spine AP and lumbar spine Lat. The results reinforce the need for radiation protection optimization, improving examination techniques and appropriate use of automatic exposure control in digital radiography. ESAK values reported in this study could further contribute to establishing local DRLs, regional DRLs and national DRLs.