Simultaneous optimization of photons and electrons for mixed beam radiotherapy.

Mueller, S; Fix, Michael; Joosten, Andreas; Henzen, Dominik; Frei, Daniel; Volken, Werner; Küng, Reto; Aebersold, Daniel; Stampanoni, M F M; Manser, Peter (2017). Simultaneous optimization of photons and electrons for mixed beam radiotherapy. Physics in medicine and biology, 62(14), pp. 5840-5860. Institute of Physics Publishing IOP 10.1088/1361-6560/aa70c5

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The aim of this work is to develop and investigate an inverse treatment planning process (TPP) for mixed beam radiotherapy (MBRT) capable of performing simultaneous optimization of photon and electron apertures. A simulated annealing based direct aperture optimization (DAO) is implemented to perform simultaneous optimization of photon and electron apertures, both shaped with the photon multileaf collimator (pMLC). Validated beam models are used as input for Monte Carlo dose calculations. Consideration of photon pMLC transmission during DAO and a weight re-optimization of the apertures after deliverable dose calculation are utilized to efficiently reduce the differences between optimized and deliverable dose distributions. The TPP for MBRT is evaluated for an academic situation with a superficial and an enlarged PTV in the depth, a left chest wall case including the internal mammary chain and a squamous cell carcinoma case. Deliverable dose distributions of MBRT plans are compared to those of modulated electron radiotherapy (MERT), photon IMRT and if available to those of clinical VMAT plans. The generated MBRT plans dosimetrically outperform the MERT, photon IMRT and VMAT plans for all investigated situations. For the clinical cases of the left chest wall and the squamous cell carcinoma, the MBRT plans cover the PTV similarly or more homogeneously than the VMAT plans, while OARs are spared considerably better with average reductions of the mean dose to parallel OARs and D 2% to serial OARs by 54% and 26%, respectively. Moreover, the low dose bath expressed as V 10% to normal tissue is substantially reduced by up to 45% compared to the VMAT plans. A TPP for MBRT including simultaneous optimization is successfully implemented and the dosimetric superiority of MBRT plans over MERT, photon IMRT and VMAT plans is demonstrated for academic and clinical situations including superficial targets with and without deep-seated part.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology > Medical Radiation Physics
04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology

UniBE Contributor:

Fix, Michael; Joosten, Andreas; Henzen, Dominik; Frei, Daniel; Volken, Werner; Küng, Reto; Aebersold, Daniel and Manser, Peter

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0031-9155

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Beatrice Scheidegger

Date Deposited:

27 Feb 2018 14:55

Last Modified:

27 Feb 2018 14:55

Publisher DOI:

10.1088/1361-6560/aa70c5

PubMed ID:

28467321

BORIS DOI:

10.7892/boris.105285

URI:

https://boris.unibe.ch/id/eprint/105285

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