Room: Exhibit Hall | Forum 8
Purpose: To measure scatter and leakage radiation from pediatric and adult patient phantoms imaged during DR and assess occupational and public exposure limits.
Methods: A newborn and 5 YO anthropomorphic phantom (ATOM, CIRS), and PMMA blocks simulating an adult male were used to measure scatter radiation from the phantomâ€™s abdomen, thorax, skull, and forearm. The phantoms were placed directly on the image receptor assembly (forearm) and tabletop (abdomen, thorax, or skull). Exposures were performed using a Philips Digital Diagnost with standard clinical protocols (kV, mAs, field size, and filtration); SID was standardized at 40 inches. A 180-cc pancake ion chamber (Accu-Gold+, Radcal) was placed 1 meter from the center of the x-ray beam aligned to midline of phantom. Results at 25 cm from center of x-ray beam were calculated. Leakage radiation was measured with the collimator closed.
Results: For an occupational worker, not wearing a Pb equivalent apron, to receive an annual exposure equal to 10% of the Maximum Permissible Dose, 5 mSv from stray radiation, standing 25 cm from a newborn/5 YO/adult, the number of annual abdomen or forearm exposures were: 6,510/505/147 and 74,405/22,645/4,400, respectively, and for a thorax and skull from a newborn/5 YO were: 20,833/1,515 and 1,990/375 exposures, respectively. For a member of the public (parent) (1 mSv/yr limit) this would equate to being present in the examination room during 1,302/101/29 abdomen exposures annually for a newborn/5 YO/adult, respectively. An occupational worker (50 mSv/yr limit), could be present for 65,100/5,050/1,470 annual exposures respectively for an abdomen examination of a newborn/5 YO/adult.
Conclusion: Based on occupational and public exposure limits, occupational staff or members of the general public standing near to a patient during a DR examination should not be required to wear Pb aprons.