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.
Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine. 2016 Jan 27 [Epub ahead of print]
Craig Norvill, Guy Jenetsky
North Coast Cancer Institute, Coffs Harbour, NSW, 2450, Australia. North Coast Cancer Institute, Lismore, NSW, 2480, Australia.