Treatment plan optimization and robustness of 106Ru eye plaque brachytherapy using a novel software tool

Publication date: Available online 6 February 2017
Source:Radiotherapy and Oncology
Author(s): Gerd Heilemann, Lukas Fetty, Martin Dulovits, Matthias Blaickner, Nicole Nesvacil, Dietmar Georg, Roman Dunavoelgyi
Background and purposeTo analyze treatment plan robustness and plan optimization strategies of ¹⁰⁶Ru eye plaque brachytherapy using a novel software tool.Materials and methodsA treatment planning software was developed that allows to calculate dose–volume metrics. Plaque misplacements were simulated and evaluated with respect to the effect on tumor coverage and dose changes in critical structures. Two treatment plan optimization approaches were analyzed: (a) reducing plaque size and (b) shifting the plaque away from organs-at-risk (OAR).ResultsMaximum tumor sizes were identified which can be covered by the prescribed dose for different robustness levels (0–2mm). For an apex height of 5mm a 1mm uncertainty yielded changes in D2% to the lens of up to ±13Gy in anterior and ±20Gy to the optic nerve in posterior tumors. By reducing the plaque size Dmean and D2% to lens, optic nerve and macula were decreased by >60% for most simulated cases. Similarly, by shifting the plaque away from the lens dose reductions of 15%/mm in anterior and even 30%/mm in central tumors were achieved.ConclusionCritical structures in the treatment of uveal melanomas with ¹⁰⁶Ru plaques can benefit from the proposed, computational treatment plan optimization.



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