Performing Shielding Calculations for Diagnostic Radiology Based on NCRP Report 147 Methodology: A Review

The purpose of this work to provide a comprehensive review and effective tool for performing shielding calculations for diagnostic radiology reliably, cost-effective and a timesaving since the shielding is the most effective element in diagnostic radiology safety design. The recommendations of National Council on Radiation Protection and Measurements (NCRP) Report No. 49, which has been the main reference for the structural radiation shielding design of diagnostic X-ray facilities for a while, are most frequently used in structural radiation shielding calculations for X-ray diagnostic facilities. The NCRP Report 49 calculating technique has undergone numerous changes over time, rendering it virtually useless because it did not take into account developments in radiology technology. With the publication of NCRP Report No. 147, the approach was corrected by giving shielding designers the ability to, in part, specify efficient barriers to diagnostic radiation settings. The NCRP Report 147 methodology for calculating radiation shielding requirements depend greatly on the shielding design goals (P) where a proposed design limit for controlled and uncontrolled areas is reduced to NCRP Report 49 levels. Further, the methodology most likely uses the concept of “dose constraint” in radiation installations as shielding design goals for the purpose of safety and protection optimization for occupational workers and the public. The previous NCRP Report 49 uses a very conservative approach in the assumption and methodology, which in return yielded with barriers much thicker than what is required in diagnostic facilities.

In this context, Federal Authority for Nuclear Regulation (FANR), the nuclear and radiological regulator for the United Arab Emirates, recently published software which developed by authors for performing radiation shielding calculations based on an algebraic computation model and the given fitting factors provided by NCRP Report No. 147. The International Atomic Energy Agency (IAEA), has taken interest to independently validate the codes of the software; and praise the functionality of the tool. The software performs shielding calculations in an effective, easy, and reliable way while being a cost-effective and a timesaving tool. The shielding is the most efficient component in an X-ray design because there are typically some time and distance restrictions because of the nature of diagnostic operations. The conservative assumptions made in the computation, such as neglecting attenuation by the patient and image receptor, overestimating the workload, occupancy, and field size, may result in actual dose values to persons being lower than dosage values.