title: Clinical significance of multi-leaf collimator calibration errors.
abstract: This planning study investigates the clinical impact of multi-leaf collimator (MLC) calibration errors on three common treatment sites; head and neck (H&N), prostate and stereotactic body radiotherapy (SBRT) for lung. All plans used using either volumetric modulated adaptive therapy or dynamic MLC techniques. Five patient plans were retrospectively selected from each treatment site, and MLC errors intentionally introduced. MLC errors of 0.7, 0.4 and 0.2 mm were sufficient to cause major violations in the PTV planning criteria for the H&N, prostate and SBRT lung plans. Mean PTV dose followed a linear trend with MLC error, increasing at rates of 3.2-5.9% per millimeter depending on treatment site. The results indicate that an MLC quality assurance program that provides sub-millimeter accuracy is an important component of intensity modulated radiotherapy delivery techniques.
authors.affiliation: North Coast Cancer Institute, Coffs Harbour, NSW, 2450, Australia. craig.norvill@genesiscancercare.com.au.
authors.forename: Craig
authors.initials: C
authors.lastname: Norvill
authors.affiliation: North Coast Cancer Institute, Lismore, NSW, 2480, Australia.
authors.forename: Guy
authors.initials: G
authors.lastname: Jenetsky
mesh_terms: D002138:Calibration; D004307:Dose-Response Relationship, Radiation; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D016634:Radiosurgery / Q000295:instrumentation*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation
keywords: Calibration; Elekta; Multi-leaf collimator; Planning