(Tuesday, 7/16/2019) 10:00 AM - 10:30 AM
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 phantom’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.
Keywords
Digital Imaging, Shielding, Scatter
Taxonomy
IM- X-ray: Radiation dosimetry & risk
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