Retrospective analysis on large-scale in-vivo dosimetric verification of total body irradiation using helical tomotherapy with optically stimulated luminescence dosimeters.

Abstract

To perform a large-scale clinical evaluation of OSLD-based in-vivo dosimetry for helical TomoTherapy-based total body irradiation, focusing on patient thickness, anatomical region, junction stability, and fraction-wise consistency. In-vivo dosimetric data from 250 patients treated with TomoTherapy-based TBI were retrospectively analyzed. RadPro myOSLD nanoDots were placed at multiple anatomical sites,including three junction regions, and measured across all treatment fractions.Percentage dose deviation between measured and expected dose was calculated.Subgroup analyses were performed by anatomical region, junction versus non-junction sites, first versus subsequent fractions, and patient thickness(thin vs obese).Statistical analyses included pass-rate evaluation, Spearman correlation,Mann–Whitney U testing, and Bland–Altman analysis. Mean dose deviations were within ±2% with standard deviations of ~4%, and pass rates within ± 7% and ± 10% were 100%. Dose deviation correlated positively with patient thickness (ρ = 0.34, p < 0.001).Junction regions and fractions showed stable performance. OSLD-based in-vivo dosimetry is a reliable and scalable method for verifying dose delivery in TomoTherapy-based TBI.