Optimization of entrance skin dose assessment: integration of a new mathematical model and Monte Carlo simulation.

Accurate estimation of entrance skin dose (ESD) is essential for radiation protection and protocol optimization. This study proposes a new analytical formulation for ESD estimation, the New Mathematical Model Equation for ESD (NMMEESD), which explicitly integrates both technical and geometric beam-formation parameters, notably the ripple factor and anode angle. These parmeters are often neglected in conventional ESD models. A dataset comprising 3800 examinations acquired from four high-frequency X-ray generators was analyzed. NMMEESD predictions were compared with experimental measurements, Monte Carlo simulations using PHITS, and the Davies and Edmonds models. The ripple factor and anode angle influence on ESD was evaluated using sensitivity analysis based on Friedman tests and Wilcoxon signed-rank post-hoc comparisons. NMMEESD predictions showed strong agreement with both experimental measurements and PHITS simulations (with deviations of ≤ 8.6%, r = 0.996, p > 0.05). Compared with conventional formulations, the proposed model demonstrated comparable predictive performance to the Davies model while offering improved robustness under practical clinical conditions and reduced discrepancies compared with the Edmonds model (up to 59.6%, p < 0.01). Sensitivity analysis indicated statistically significant ESD variations associated with ripple factor and anode angle (p < 0.001). Furthermore, the NMMEESD analytical model provided instantaneous dose estimates. The NMMEESD model provides a reliable, non-invasive analytical approach for ESD estimation. Explicit inclusion of ripple factor and anode angle in the proposed formulation improves predictive dose estimation accuracy under realistic operating conditions, offering measurable practical benefit for routine clinical dosimetry.