Objective: To determine the entrance surface dose level in common diagnostic x-ray examinations at Songklanagarind Hospital.

Materials and methods: The air kerma was measured by ionization chamber at the x-ray equipment manufactured by Toshiba Model KXO-60 G/DT-BTH in this study. Skin dose was determined in 80 medium-sized patients during January 2008 - January 2009 in different projections: chest posterior-anterior (PA), lumbar spine anterior-posterior (AP) and lateral, pelvis AP, abdomen AP, skull AP/PA and lateral. Compare the average dose value with IAEA dose reference level (DRL).

Results: The average entrance surface dose (ESD) of 7 different positions were 0.29, 2.98, 10.30, 1.62, 2.86, 4.40 and 3.28 mGy. The third quartile doses were 0.36, 3.16, 12.69, 2.06, 3.68, 5.22 and 3.57 mGy compared with the reference level (IAEA BSS) were 2, 0.4, 10, 30, 10, 10, 5, 3 mGy.

Conclusion: Most of the entrance surface dose levels were generally within the IAEA dose reference level (DRL). However, the skull lateral ESD was 3.28 mGy was higher than the DRL was 3 mGy according to improper radiographic technique.

Key words: entrance surface dose (ESD), dose reference level (DRL), common diagnostic x-ray examination