Assessing Radiation Safety in CT Scanning Rooms: Evaluation of Shielding Guidelines Based on NCRP 147

초록

The growing use of computed tomography (CT) in diagnostic radiology emphasizes the need for effective radiation safety measures in CT scanning rooms. This study evaluated shielding guidelines based on the National Council on Radiation Protection and Measurements (NCRP) Report No. 147. Shielding requirements were evaluated using data from Korea’s Health Insurance Review and Assessment Service and considered based on hospital size, scan frequency, and exposure conditions. Scatter radiation was measured experimentally using head, chest, and abdomen pelvis phantoms at distance of 120 cm from the isocenter under realistic hospital settings to evaluate calculated shielding thickness. A one-month cumulative scatter assessment was additionally performed using a CR cassette with a 0.1 & 2.0 mmPb step wedge placed inside the CT room. The results showed that calculated scatter doses were 43%-63% higher than the measured dosimeter values across all examined regions, indicating that the NCRP 147 reference data. The cumulative monthly dose also remained below about 25% of the regulatory annual limit, supporting the overall safety limits. The measured and calculated doses assessed the applicability of NCRP 147 formulas for shielding design. These findings suggest that while NCRP 147 provides sufficiently conservative shielding estimates, there is potential for optimized shielding design in Korean CT facilities without compromising radiation safety.

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