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.

Characterization of the on-board megavoltage imager in a magnetic resonance-guided radiotherapy machine for beam output checks.

We characterized the on-board megavoltage imager (MVI) of a magnetic resonance-guided radiotherapy machine for beam output checks. Linearity and repeatability of its dose response were investigated. Alignment relative to the beam under clinical circumstances was evaluated for a year using daily measurements.

Survey on fan-beam computed tomography for radiotherapy: Current implementation and future perspectives of motion management and surface guidance devices.

Background And Purpose: This work reports on the results of a survey performed on the use of computed tomography (CT) imaging for motion management, surface guidance devices, and their quality assurance (QA). Additionally, it details the collected user insights regarding professional needs in CT for radiotherapy. The purpose of the survey is to understand current practice, professional needs and future directions in the field of fan-beam CT in radiation therapy (RT).

Survey on fan-beam computed tomography for radiotherapy: Imaging for dose calculation and delineation.

Background And Purpose: To obtain an understanding of current practice, professional needs and future directions in the field of fan-beam CT in RT, a survey was conducted. This work presents the collected information regarding the use of CT imaging for dose calculation and structure delineation.

Materials And Methods: An online institutional survey was distributed to medical physics experts employed at Belgian and Dutch radiotherapy institutions to assess the status, challenges, and future directions of QA practices for fan-beam CT.

Beam output checks of a commercial high-field magnetic resonance-guided radiotherapy machine with its on-board megavoltage imager.

Beam output checks of a commercial high-field magnetic resonance-guided radiotherapy machine can be performed with its on-board megavoltage imager (MVI). This is a fast and efficient method, but only recommended for daily checks. The aim of our study was to show its suitability for weekly checks by investigating its long-term agreement with the golden standard: ionization chamber measurements in a water tank.

Local seed displacement from Day 0 to Day 30 in I-125 permanent prostate brachytherapy: A detailed, computed tomography-based analysis.

Purpose: To accurately quantify local seed displacement from Day 0 to Day 30 for our brachytherapy procedure. To quantify seed loss/migration and to identify the locations from where seeds are missing.

Methods And Materials: Seed displacements were analyzed in 62 consecutive patients, who received brachytherapy with stranded I-125 seeds.