MR-Linac Radiotherapy - The Beam Angle Selection Problem

Rik Bijman; Linda Rossi; Tomas Janssen; Peter de Ruiter; Baukelien van Triest; Sebastiaan Breedveld; Jan-Jakob Sonke; Ben Heijmen

doi:10.3389/fonc.2021.717681

MR-Linac Radiotherapy - The Beam Angle Selection Problem

Rik Bijman^*, Linda Rossi, Tomas Janssen, Peter de Ruiter, Baukelien van Triest, Sebastiaan Breedveld, Jan-Jakob Sonke, Ben Heijmen

^*Corresponding author for this work

Radiotherapy

Research output: Contribution to journal › Article › Academic › peer-review

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Abstract

BACKGROUND: With the large-scale introduction of volumetric modulated arc therapy (VMAT), selection of optimal beam angles for coplanar static-beam IMRT has increasingly become obsolete. Due to unavailability of VMAT in current MR-linacs, the problem has re-gained importance. An application for automated IMRT treatment planning with integrated, patient-specific computer-optimization of beam angles (BAO) was used to systematically investigate computer-aided generation of beam angle class solutions (CS) for replacement of computationally expensive patient-specific BAO. Rectal cancer was used as a model case.

MATERIALS AND METHODS: 23 patients treated at a Unity MR-linac were included. BAOx plans (x=7-12 beams) were generated for all patients. Analyses of BAO12 plans resulted in CSx class solutions. BAOx plans, CSx plans, and plans with equi-angular setups (EQUIx, x=9-56) were mutually compared.

RESULTS: For x>7, plan quality for CSx and BAOx was highly similar, while both were superior to EQUIx. E.g. with CS9, bowel/bladder Dmean reduced by 22% [11%, 38%] compared to EQUI9 (p<0.001). For equal plan quality, the number of EQUI beams had to be doubled compared to BAO and CS.

CONCLUSIONS: Computer-generated beam angle CS could replace individualized BAO without loss in plan quality, while reducing planning complexity and calculation times, and resulting in a simpler clinical workflow. CS and BAO largely outperformed equi-angular treatment. With the developed CS, time consuming beam angle re-optimization in daily adaptive MR-linac treatment could be avoided. Further systematic research on computerized development of beam angle class solutions for MR-linac treatment planning is warranted.

Original language	English
Article number	717681
Journal	Frontiers in Oncology
Volume	11
DOIs	https://doi.org/10.3389/fonc.2021.717681
Publication status	Published - 1 Oct 2021

Bibliographical note

FUNDING:
This work was in part funded by a research grant of Elekta AB (Stockholm, Sweden). Erasmus MC Cancer Institute also has a research collaboration with Accuray Inc, Sunnyvale, USA. The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.

Copyright © 2021 Bijman, Rossi, Janssen, de Ruiter, van Triest, Breedveld, Sonke and Heijmen.

UN SDGs

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Cite this

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title = "MR-Linac Radiotherapy - The Beam Angle Selection Problem",

abstract = "BACKGROUND: With the large-scale introduction of volumetric modulated arc therapy (VMAT), selection of optimal beam angles for coplanar static-beam IMRT has increasingly become obsolete. Due to unavailability of VMAT in current MR-linacs, the problem has re-gained importance. An application for automated IMRT treatment planning with integrated, patient-specific computer-optimization of beam angles (BAO) was used to systematically investigate computer-aided generation of beam angle class solutions (CS) for replacement of computationally expensive patient-specific BAO. Rectal cancer was used as a model case.MATERIALS AND METHODS: 23 patients treated at a Unity MR-linac were included. BAOx plans (x=7-12 beams) were generated for all patients. Analyses of BAO12 plans resulted in CSx class solutions. BAOx plans, CSx plans, and plans with equi-angular setups (EQUIx, x=9-56) were mutually compared.RESULTS: For x>7, plan quality for CSx and BAOx was highly similar, while both were superior to EQUIx. E.g. with CS9, bowel/bladder Dmean reduced by 22% [11%, 38%] compared to EQUI9 (p<0.001). For equal plan quality, the number of EQUI beams had to be doubled compared to BAO and CS.CONCLUSIONS: Computer-generated beam angle CS could replace individualized BAO without loss in plan quality, while reducing planning complexity and calculation times, and resulting in a simpler clinical workflow. CS and BAO largely outperformed equi-angular treatment. With the developed CS, time consuming beam angle re-optimization in daily adaptive MR-linac treatment could be avoided. Further systematic research on computerized development of beam angle class solutions for MR-linac treatment planning is warranted.",

author = "Rik Bijman and Linda Rossi and Tomas Janssen and {de Ruiter}, Peter and {van Triest}, Baukelien and Sebastiaan Breedveld and Jan-Jakob Sonke and Ben Heijmen",

note = "FUNDING: This work was in part funded by a research grant of Elekta AB (Stockholm, Sweden). Erasmus MC Cancer Institute also has a research collaboration with Accuray Inc, Sunnyvale, USA. The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication. Copyright {\textcopyright} 2021 Bijman, Rossi, Janssen, de Ruiter, van Triest, Breedveld, Sonke and Heijmen.",

year = "2021",

month = oct,

day = "1",

doi = "10.3389/fonc.2021.717681",

language = "English",

volume = "11",

journal = "Frontiers in Oncology",

issn = "2234-943X",

publisher = "Frontiers Media SA",

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TY - JOUR

T1 - MR-Linac Radiotherapy - The Beam Angle Selection Problem

AU - Bijman, Rik

AU - Rossi, Linda

AU - Janssen, Tomas

AU - de Ruiter, Peter

AU - van Triest, Baukelien

AU - Breedveld, Sebastiaan

AU - Sonke, Jan-Jakob

AU - Heijmen, Ben

N1 - FUNDING: This work was in part funded by a research grant of Elekta AB (Stockholm, Sweden). Erasmus MC Cancer Institute also has a research collaboration with Accuray Inc, Sunnyvale, USA. The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication. Copyright © 2021 Bijman, Rossi, Janssen, de Ruiter, van Triest, Breedveld, Sonke and Heijmen.

PY - 2021/10/1

Y1 - 2021/10/1

N2 - BACKGROUND: With the large-scale introduction of volumetric modulated arc therapy (VMAT), selection of optimal beam angles for coplanar static-beam IMRT has increasingly become obsolete. Due to unavailability of VMAT in current MR-linacs, the problem has re-gained importance. An application for automated IMRT treatment planning with integrated, patient-specific computer-optimization of beam angles (BAO) was used to systematically investigate computer-aided generation of beam angle class solutions (CS) for replacement of computationally expensive patient-specific BAO. Rectal cancer was used as a model case.MATERIALS AND METHODS: 23 patients treated at a Unity MR-linac were included. BAOx plans (x=7-12 beams) were generated for all patients. Analyses of BAO12 plans resulted in CSx class solutions. BAOx plans, CSx plans, and plans with equi-angular setups (EQUIx, x=9-56) were mutually compared.RESULTS: For x>7, plan quality for CSx and BAOx was highly similar, while both were superior to EQUIx. E.g. with CS9, bowel/bladder Dmean reduced by 22% [11%, 38%] compared to EQUI9 (p<0.001). For equal plan quality, the number of EQUI beams had to be doubled compared to BAO and CS.CONCLUSIONS: Computer-generated beam angle CS could replace individualized BAO without loss in plan quality, while reducing planning complexity and calculation times, and resulting in a simpler clinical workflow. CS and BAO largely outperformed equi-angular treatment. With the developed CS, time consuming beam angle re-optimization in daily adaptive MR-linac treatment could be avoided. Further systematic research on computerized development of beam angle class solutions for MR-linac treatment planning is warranted.

AB - BACKGROUND: With the large-scale introduction of volumetric modulated arc therapy (VMAT), selection of optimal beam angles for coplanar static-beam IMRT has increasingly become obsolete. Due to unavailability of VMAT in current MR-linacs, the problem has re-gained importance. An application for automated IMRT treatment planning with integrated, patient-specific computer-optimization of beam angles (BAO) was used to systematically investigate computer-aided generation of beam angle class solutions (CS) for replacement of computationally expensive patient-specific BAO. Rectal cancer was used as a model case.MATERIALS AND METHODS: 23 patients treated at a Unity MR-linac were included. BAOx plans (x=7-12 beams) were generated for all patients. Analyses of BAO12 plans resulted in CSx class solutions. BAOx plans, CSx plans, and plans with equi-angular setups (EQUIx, x=9-56) were mutually compared.RESULTS: For x>7, plan quality for CSx and BAOx was highly similar, while both were superior to EQUIx. E.g. with CS9, bowel/bladder Dmean reduced by 22% [11%, 38%] compared to EQUI9 (p<0.001). For equal plan quality, the number of EQUI beams had to be doubled compared to BAO and CS.CONCLUSIONS: Computer-generated beam angle CS could replace individualized BAO without loss in plan quality, while reducing planning complexity and calculation times, and resulting in a simpler clinical workflow. CS and BAO largely outperformed equi-angular treatment. With the developed CS, time consuming beam angle re-optimization in daily adaptive MR-linac treatment could be avoided. Further systematic research on computerized development of beam angle class solutions for MR-linac treatment planning is warranted.

U2 - 10.3389/fonc.2021.717681

DO - 10.3389/fonc.2021.717681

M3 - Article

C2 - 34660281

SN - 2234-943X

VL - 11

JO - Frontiers in Oncology

JF - Frontiers in Oncology

M1 - 717681

ER -

MR-Linac Radiotherapy - The Beam Angle Selection Problem

Abstract

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