<![CDATA[Accurate radiation shielding calculations are essential for radiation protection and medical physics education. This study developed and numerically verified an interactive desktop application for broad-beam photon shielding calculations using the Archer transmission model. The application integrates published Monte Carlo-derived fitting parameters for Tc-99m, I-131, F-18, and Lu-177 in lead, concrete, and steel, enabling forward and inverse shielding calculations with buildup effects and selectable weekly design goals of 0.02 mSv/week. Numerical verification was performed by comparing application outputs with independent calculations and published reference data. For the Tc-99m lead shielding example (0.637 mm), the application reproduced the published transmission result, while inverse–forward round-trip calculations achieved a composite target within a relative residual of approximately . Additional comparisons were conducted using published fractional-value layers for nine radionuclide–material combinations. The results demonstrate numerical consistency in the implemented calculations and provide an interactive framework for exploring photon attenuation and shielding thickness in medical physics education. However, Ga-68 calculations remain based on unvalidated F-18 surrogate parameters, and multilayer shielding estimates have not been independently validated against experimental or Monte Carlo reference data. Therefore, the application is intended for educational use rather than clinical shielding design.]]>
