Bubble technique for evaluating effective dose of diagnostic X-rays: a feasibility study

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 degrees C (for abdomen AP) or 22 degrees C (for chest PA) to optimize counting, and the assessed effective doses for males and females were 66.75 +/- 10.23 microSv and 66.47 +/- 9.89 microSv, respectively, for each chest PA X-ray exposure. The abdominal AP X-ray exposure doses were 1183.73 +/- 124.29 microSv and 976.70 +/- 120.13 microSv 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.