Bubble technique for evaluating effective dose of diagnostic X-rays

This study examined the feasibility of applying the bubble technique to evaluate effective dose for diagnostic X-rays. A BTI-GAMMA bubble detector from Bubble Technology Industries was used for gamma detection. A multi-slab acrylic (PMMA) phantom was fabricated to quantify the effective dose E based on an ICRP-60 report. Accordingly, the bubble detectors were evaluated through preliminary tests to ascertain both the reproducibility of specific X-ray doses and the linearity of multiple X-ray doses. Qualified bubble detectors were then inserted into a multi-slab acrylic phantom. The positions of the inserted bubbles closely corresponded with the position of represented organs or tissues. The effective dose E of X-ray was determined in 12 organ and tissue samples. The bubble detector was maintained at either 21.5°C (for abdomen AP) or 22°C (for chest PA) to optimize counting, and the assessed effective doses for males and females were 66.75 ± 10.23 μSv and 66.47 ± 9.89 μSv, respectively, for each chest PA X-ray exposure. The abdominal AP X-ray exposure doses were 1183.73 ± 124.29 μSv and 976.70 ± 120.13 μSv for males and females, respectively. Controlling and holding the bubble detector at an optimal ambient temperature during X-ray exposure was the most important issue in practical application, and the optimal temperature had to be adjusted slightly with incident X-ray to effectively suppress the largest bubbles to enable easy reading.