Radiation shielding transmission data for modern digital radiography.

Background Purpose Methods Results Conclusion Radiography is one of the most widely used x‐ray imaging modalities. In National Council on Radiation Protection and Measurements (NCRP) Report No. 147, transmission data for radiographic systems were evaluated on those installed before 2000. For x‐ray systems (except intraoral dental) manufactured on or after June 10, 2006, the U.S. required minimum half‐value layer (HVL) was increased; for example, 2.9 (2.3) mm Al at 80 kV, where the value in parenthesis denotes the earlier requirement before the above date.To calculate the transmission of the broad x‐ray beam of modern digital radiography (DR) through shielding materials.X‐ray beam HVLs on two DR systems (Agfa DR 600, GE Revolution XR/d) were measured in 10 kV increments between 60 and 120 kV, with a calibrated ionization chamber (Radcal model 10 × 5‐60) and varying thickness of aluminum 1100 plates. Monte Carlo (Geant4) simulation was performed to calculate the transmission of broad x‐ray beams through lead, concrete, gypsum, and steel, with x‐ray HVLs matching those of the DR 600 at two beam filtrations (default, 1 mm Al plus 0.1 mm Cu added filtration). The transmission data were fitted to the Archer equation.HVLs on two DR systems with default beam filtration were consistent (median difference, 2.1%; maximum difference, 5.5%). An additional beam filtration option (1 mm Al plus 0.1 mm Cu) on the DR 600 substantially increased HVLs by 45.2%–61.2%. Transmission fitting parameters were provided for seven tube voltages (60–120 kV) at two beam filtrations.This work presents transmission data for modern DR systems, indicating increased x‐ray beam filtration compared to the primary x‐ray beam in NCRP Report No. 147. The updated transmission data can enhance structural shielding evaluations at individual tube voltages or with a workload distribution. [ABSTRACT FROM AUTHOR]