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Emulating the Delivery of Sawtooth Proton Arc Therapy Plans on a Cyclotron-Based Proton Beam Therapy System
by
, , , , and
Samuel Burford-Eyre
1,*,
Adam Aitkenhead
2,3,
Jack D. Aylward
1,2,4,
Nicholas T. Henthorn
2,3,
Samuel P. Ingram
2,3,
Ranald Mackay
2,3,
Samuel Manger
2,3,
Michael J. Merchant
3,
Peter Sitch
2,3,
John-William Warmenhoven
2,3 and
Robert B. Appleby
1,* 1
Department of Physics and Astronomy and the Cockcroft Institute, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester M13 9PL, UK
2
Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester M20 4BX, UK
3
Division of Cancer Sciences, Faculty of Biology Medicine and Heath, The University of Manchester, Manchester M13 9PL, UK
4
School of Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
*
Authors to whom correspondence should be addressed.
Cancers 2024, 16(19), 3315; https://doi.org/10.3390/cancers16193315 (registering DOI)
Submission received: 31 July 2024
/
Revised: 15 September 2024
/
Accepted: 19 September 2024
/
Published: 27 September 2024
(This article belongs to the Special Issue The Advance of Pencil Beam Scanning Proton Beam Therapy in Cancers)
Simple Summary
The overall delivery time of proton arc therapy (PAT) plans on current clinical systems must be evaluated due to high upward energy layer switching times (ELSTs) in order to identify clinically suitable methods of PAT planning and delivery. We present the application of an emulator for modelling the delivery of `sawtooth’ PAT plans on an existing cyclotron-based system. We show that this method of PAT planning consistently requires a longer delivery time than static intensity modulated proton therapy (IMPT) and that delivering PAT using a continuous gantry rotation remains the optimum delivery method on such systems. This analysis shows that the delivery of PAT plans generated using the simplified sawtooth PAT planning approach may be clinically infeasible without further developments to the existing clinical technologies.
Abstract
Purpose: To evaluate and compare the deliverability of `sawtooth’ proton arc therapy (PAT) plans relative to static intensity modulated proton therapy (IMPT) at a cyclotron-based clinical facility. Methods: The delivery of single and dual arc Sawtooth PAT plans for an abdominal CT phantom and multiple clinical cases of brain, head and neck (H&N) and base of skull (BoS) targets was emulated under the step-and-shoot and continuous PAT delivery regimes and compared to that of a corresponding static IMPT plan. Results: Continuous PAT delivery increased the time associated with beam delivery and gantry movement in single/dual PAT plans by 4.86/7.34 min (brain), 7.51/12.40 min (BoS) and 6.59/10.57 min (H&N) on average relative to static IMPT. Step-and-shoot PAT increased this delivery time further by 4.79 min on average as the delivery was limited by gantry motion. Conclusions: The emulator can approximately model clinical sawtooth PAT delivery but requires experimental validation. No clear benefit was observed regarding beam-on time for sawtooth PAT relative to static IMPT.
