The positional accuracy of multileaf collimators (MLC) is crucial in ensuring precise delivery of intensity-modulated radiotherapy (IMRT). The aim of this planning study was to investigate the dosimetric impact of systematic MLC positional errors on step and shoot IMRT of @entity263 . A total of 12 perturbations of MLC leaf banks were introduced to six prostate IMRT treatment plans to simulate MLC systematic positional errors. Dose volume histograms (DVHs) were generated for the extraction of dose endpoint parameters. Plans were evaluated in terms of changes to the defined endpoint dose parameters, conformity index (CI) and healthy tissue avoidance (HTA) to planning target volume ( @entity343 ), rectum and bladder. Negative perturbations of MLC had been found to produce greater changes to endpoint dose parameters than positive perturbations of MLC (p  <  0.01). Negative and positive asynchronised MLC perturbations of -1  mm resulted in median changes in D(95) of -1.2 and 0.9% respectively. Negative and positive @entity16285 of 1  mm in one direction resulted in median changes in D(95) of -2.3 and 1.8% respectively. Doses to rectum were generally more sensitive to systematic @entity2246 compared to bladder (p  <  0.01). Negative and positive @entity16285 of 1  mm in one direction resulted in median changes in endpoint dose parameters of rectum and bladder from 1.0 to 2.5%. Maximum reduction of -4.4 and -7.3% were recorded for conformity index (CI) and healthy tissue avoidance (HTA) respectively due to synchronised MLC perturbation of 1  mm. @entity2246 resulted in dosimetric changes in IMRT plans for prostate.

Dosimetric impact of systematic MLC positional errors on step and shoot IMRT for XXXX : a planning study.

@entity2246 :: ('MESH:D008661', 'Disease') :: ['MLC errors'] @entity263 :: ('MESH:D011471', 'Disease') :: ['prostate cancer'] @entity343 :: ('187978', 'Species') :: ['PTV'] @entity16285 :: ('MESH:C536875', 'Disease') :: ['synchronised MLC perturbations']
@entity263 :: (MESH:D011471,Disease) :: ['prostate cancer']
