Within the assumptions of the model: NCRP-published scatter fractions for the listed modalities, inverse-square distance falloff, and OSHA-minimum 0.5mm Pb apron attenuation. Real-world variables wraparound shielding, beam-on time outliers, scatter geometry can shift the actual exposure up or down. The estimate is most useful as a personal awareness tool and a sanity check, not as a calibrated reading.