Mitigating dosimetric perturbations from large metal implants utilizing spot-scanning proton arc therapy.

Document Type

Article

Publication Date

2-26-2026

Publication Title

Medical dosimetry : official journal of the American Association of Medical Dosimetrists

Abstract

Conventional intensity modulated proton therapy (IMPT) techniques are exquisitely sensitive to setup and range uncertainties in the presence of high-density metal implants. Herein we introduce a spot-scanning proton arc (SPArc) approach to improve the nominal plan quality near metal implants by increasing the degrees of freedom. 4-field IMPT and single-arc SPArc plans were generated for 5 patients with target volumes circumscribed or traversed by metal implants. Robust optimization was used (parameters: ± 3.5% range, ± 3/5 mm setup uncertainties). Twenty-six perturbation scenarios per patient were generated to assess robustness. Nominal plan quality was evaluated by dose volume histogram (DVH) target coverage and hotspot metrics. Target volume homogeneity was assessed via standard deviation (SD), interquartile range (IQR), range width, Levene's variance test, and homogeneity index (HI). Robustness was quantified via Levene and mean DVH 95% confidence interval (95% CI) width. Compared to IMPT, SPArc significantly improved target coverage at all tested volume and dose levels. Hotspots were significantly reduced at V

Volume

S0958-3947

Issue

26

First Page

00009-9

DOI

10.1016/j.meddos.2026.01.006

ISSN

1873-4022

PubMed ID

41760448

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