Technical Note: Motion‐perturbation method applied to dosimetry of dynamic MLC target tracking—A proof‐of‐concept

Abstract

Based on current results and prior benchmarks of VMS accuracy, the authors postulate that this approach should be applicable to any MLC-tracking treatments where leaf speeds do not exceed those of the current Varian accelerators.

A fast 4D IMRT/VMAT planning method based on segment aperture morphing

“…Various research groups and vendors are currently working on external MLC control systems that will allow segment by segment control of MLC positions based on the patient's current breathing phase as well as segment by segment dose accumulation algorithyms. 23,[31][32][33][34][35] Typical adult breathing rates are 12-18 breaths per minute. 36 Fast et al have found Elekta agility MLC segment changing lag times on the order of 37-69 ms.…”

Novel methodologies for dosimetry audits: Adapting to advanced radiotherapy techniques

“…Implementing this method in dosimetry audits could provide an estimate of volumetric, time-resolved dose errors in planned dose distributions and thus more clinically relevant information. Virtual motion simulation methods have also been developed for the purpose of dynamic MLC-tracking verification using a commercial bi-planar dosimeter, where time-resolved measurements allow identifying transient dose errors during VMAT delivery [68] , [69] , [70] . For dosimetry audits, this approach could be applied to discriminate between errors in the dose delivered to moving targets, which could be due to either target motion or erroneous motion or behaviour of linac parts.…”