Multileaf collimator characterization and modeling for a 1.5 T MR-linac using static synchronous and asynchronous sweeping gaps.

The Elekta unity MR-linac delivers step-and-shoot intensity modulated radiotherapy plans using a multileaf collimator (MLC) based on the Agility MLC used on conventional Elekta linacs. Currently, details of the physical Unity MLC and the computational model within its treatment planning system (TPS)Monacoare lacking in published literature. Recently, a novel approach to characterize the physical properties of MLCs was introduced using dynamic synchronous and asynchronous sweeping gap (aSG) tests.

Dosimetric impact of contouring and image registration variability on dynamic I prostate brachytherapy.

Purpose: The quality of permanent prostate brachytherapy can be increased by addition of imaging modalities in the intraoperative procedure. This addition involves image registration, which inherently has inter- and intraobserver variabilities. We sought to quantify the inter- and intraobserver variabilities in geometry and dosimetry for contouring and image registration and analyze the results for our dynamic I brachytherapy procedure.

Elective breast radiotherapy including level I and II lymph nodes: A planning study with the humeral head as planning risk volume.

Background: The aim of this study was to assess the dose to the humeral head planning risk volume with the currently used high tangential fields (HTF) and compare different planning techniques for breast radiotherapy including axillary level I and II lymph nodes (PTVn) while sparing the humeral head.

Methods: Ten patients with left-sided breast cancer were enrolled in a planning study with 16 fractions of 2.66 Gy.