Spatiotemporal radiotherapy planning using a global optimization approach

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Authors
Adibi, Ali
Salari, Ehsan
Issue Date
2018-02-06
Type
Article
Language
en_US
Keywords
Spatiotemporal planning , EUBED , Global optimization , Intensity-modulated radiotherapy
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Abstract

This paper aims at quantifying the extent of potential therapeutic gain, measured using biologically effective dose (BED), that can be achieved by altering the radiation dose distribution over treatment sessions in fractionated radiotherapy. To that end, a spatiotemporally integrated planning approach is developed, where the spatial and temporal dose modulations are optimized simultaneously. The concept of equivalent uniform BED (EUBED) is used to quantify and compare the clinical quality of spatiotemporally heterogeneous dose distributions in target and critical structures. This gives rise to a large-scale non-convex treatment-plan optimization problem, which is solved using global optimization techniques. The proposed spatiotemporal planning approach is tested on two stylized cancer cases resembling two different tumor sites and sensitivity analysis is performed for radiobiological and EUBED parameters. Numerical results validate that spatiotemporal plans are capable of delivering a larger BED to the target volume without increasing the BED in critical structures compared to conventional time-invariant plans. In particular, this additional gain is attributed to the irradiation of different regions of the target volume at different treatment sessions. Additionally, the trade-off between the potential therapeutic gain and the number of distinct dose distributions is quantified, which suggests a diminishing marginal gain as the number of dose distributions increases.

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Citation
Ali Adibi and Ehsan Salari 2018 Phys. Med. Biol. 63 035040
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IOP Publishing
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DOI
ISSN
0031-9155
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