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First experimental evaluation of multi-target multileaf collimator tracking during volumetric modulated arc therapy for locally advanced prostate cancer

Authors :
Linda J. Bell
Per Rugaard Poulsen
John Kipritidis
Stephanie Roderick
Paul J. Keall
Y Ge
Doan Nguyen
Emily A. Hewson
Andrew Dipuglia
Ricky O'Brien
Jeremy T. Booth
Thomas Eade
Source :
Radiotherapy & Oncology, Hewson, E A, Dipuglia, A, Kipritidis, J, Ge, Y, O'Brien, R, Roderick, S, Bell, L, Poulsen, P R, Eade, T, Booth, J T, Keall, P J & Nguyen, D T 2021, ' First experimental evaluation of multi-target multileaf collimator tracking during volumetric modulated arc therapy for locally advanced prostate cancer ', Radiotherapy and Oncology, vol. 160, pp. 212-220 . https://doi.org/10.1016/j.radonc.2021.05.001
Publication Year :
2021
Publisher :
Elsevier BV, 2021.

Abstract

Purpose Locally advanced and oligometastatic cancer patients require radiotherapy treatment to multiple independently moving targets. There is no existing commercial solution that can simultaneously track and treat multiple targets. This study experimentally implemented and evaluated a real-time multi-target tracking system for locally advanced prostate cancer. Methods Real-time multi-target MLC tracking was integrated with 3D x-ray image guidance on a standard linac. Three locally advanced prostate cancer treatment plans were delivered to a static lymph node phantom and dynamic prostate phantom that reproduced three prostate trajectories. Treatments were delivered using multi-target MLC tracking, single-target MLC tracking, and no tracking. Doses were measured using Gafchromic film placed in the dynamic and static phantoms. Dosimetric error was quantified by the 2%/2 mm gamma failure rate. Geometric error was evaluated as the misalignment between target and aperture positions. The multi-target tracking system latency was measured. Results The mean (range) gamma failure rates for the prostate and lymph nodes, were 18.6% (5.2%, 28.5%) and 7.5% (1.1%, 13.7%) with multi-target tracking, 7.9% (0.7%, 15.4%) and 37.8% (18.0%, 57.9%) with single-target tracking, and 38.1% (0.6%, 75.3%) and 37.2% (29%, 45.3%) without tracking. Multi-target tracking had the lowest geometric error with means and standard deviations within 0.2 ± 1.5 for the prostate and 0.0 ± 0.3 mm for the lymph nodes. The latency was 730 ± 20 ms. Conclusion This study presented the first experimental implementation of multi-target tracking to independently track prostate and lymph node displacement during VMAT. Multi-target tracking reduced dosimetric and geometric errors compared to single-target tracking and no tracking.

Details

ISSN :
01678140
Volume :
160
Database :
OpenAIRE
Journal :
Radiotherapy and Oncology
Accession number :
edsair.doi.dedup.....597b4a369bc50dbcdf0d314147c539b6
Full Text :
https://doi.org/10.1016/j.radonc.2021.05.001