Journal article
Reducing MRI-guided radiotherapy planning and delivery times via efficient leaf sequencing and segment shape optimization algorithms
Physics in medicine & biology, Vol.67(5), p.55005
02/24/2022
DOI: 10.1088/1361-6560/ac5299
PMID: 35130528
Abstract
Extended treatment session times are an operational limitation in magnetic resonance imaging guided adaptive radiotherapy (MRIgRT). In this study a novel leaf sequencing algorithm called optimal fluence levels (OFL) and an optimization algorithm called pseudo gradient descent (PGD) are evaluated with respect to plan quality, beam complexity, and the ability to reduce treatment session times on the Elekta Unity MRIgRT system.
Ten total patients were evaluated on this Institutional Review Board approved study: three with prostate cancer, three with oligometastases, two with pancreatic cancer, and two with liver cancer. Plans were generated using the clinical Monaco Hyperion optimizer and leaf sequencer and then re-optimized using OFL and PGD (OFL + PGD) while holding all IMRT constraints and planning parameters constant. All plans were normalized to ensure 95% of the PTV received the prescription dose. A paired t-test was used to evaluate statistical significance.
Plan quality in terms of dosimetric OAR sparing was found to be equivalent between the OFL + PGD and conventional Monaco Hyperion optimizer plans. The OFL + PGD plans had a reduction in optimization time of 51.4% ± 5.0% (
= 0.002) and reduction in treatment delivery time of 10.6% ± 7.5% (
= 0.005). OFL + PGD generated plans had on average 13.2% ± 12.6% fewer multi-leaf collimator (MLC) segments (
= 0.009) and 0.1 ± 0.1 lower plan averaged beam modulation (PM) (
= 0.004) relative to the Monaco Hyperion plans.
The OFL + PGD algorithms more quickly generate Unity treatment plans that are faster to deliver than with the conventional approach and without compromising dosimetric plan quality. This is likely due to a delivery complexity reduction enabled by OFL + PGD relative to the Monaco Hyperion plans.
Details
- Title: Subtitle
- Reducing MRI-guided radiotherapy planning and delivery times via efficient leaf sequencing and segment shape optimization algorithms
- Creators
- Jeffrey E Snyder - University of Iowa Hospitals and ClinicsJoël St-Aubin - University of IowaSridhar Yaddanapudi - University of IowaSpencer Marshall - ElektaSarah Strand - University of Iowa Hospitals and ClinicsStanley Kruger - University of IowaRyan Flynn - University of Iowa Hospitals and ClinicsDaniel E Hyer - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Physics in medicine & biology, Vol.67(5), p.55005
- DOI
- 10.1088/1361-6560/ac5299
- PMID
- 35130528
- NLM abbreviation
- Phys Med Biol
- ISSN
- 0031-9155
- eISSN
- 1361-6560
- Grant note
- DOI: 10.13039/501100002669, name: Elekta
- Language
- English
- Date published
- 02/24/2022
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Radiation Oncology
- Record Identifier
- 9984313074502771
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