MR-OCTAVIUS 4D with 1500 MR and 1600 MR arrays is suitable for plan QA in a 1.5 T MRI-linac.

To ensure the accuracy of radiation delivery to patients in a 1.5 T MRI-linac, the implementation of quality assurance (QA) devices compatible with MR technology is essential. The OCTAVIUS 4D MR, made by PTW (Freiburg, Germany) is designed to ensure consistent and ideal alignment of its detectors with the direction of each beam segment.

Influence of magnetic field on a novel scintillation dosimeter in a 1.5 T MR-linac.

For commissioning and quality assurance for adaptive workflows on the MR-linac, a dosimeter which can measure time-resolved dose during MR image acquisition is desired. The Blue Physics model 10 scintillation dosimeter is potentially an ideal detector for such measurements. However, some detectors can be influenced by the magnetic field of the MR-linac.

Performance of the HYPERSCINT scintillation dosimetry research platform for the 1.5 T MR-linac.

Adaptive radiotherapy techniques available on the MR-linac, such as daily plan adaptation, gating, and dynamic tracking, require versatile dosimetric detectors to validate end-to-end workflows. Plastic scintillator detectors (PSDs) offer great potential with features including: water equivalency, MRI-compatibility, and time-resolved dose measurements. Here, we characterize the performance of the HYPERSCINT RP-200 PSD (MedScint, Quebec, CA) in a 1.

Acceptance procedure for the linear accelerator component of the 1.5 T MRI-linac.

Purpose: To develop and implement an acceptance procedure for the new Elekta Unity 1.5 T MRI-linac.

Methods: Tests were adopted and, where necessary adapted, from AAPM TG106 and TG142, IEC 60976 and NCS 9 and NCS 22 guidelines.

Machine QA for the Elekta Unity system: A Report from the Elekta MR-linac consortium.

Over the last few years, magnetic resonance image-guided radiotherapy systems have been introduced into the clinic, allowing for daily online plan adaption. While quality assurance (QA) is similar to conventional radiotherapy systems, there is a need to introduce or modify measurement techniques. As yet, there is no consensus guidance on the QA equipment and test requirements for such systems.

Feasibility of stereotactic radiotherapy using a 1.5 T MR-linac: Multi-fraction treatment of pelvic lymph node oligometastases.

Online adaptive radiotherapy using the 1.5 Tesla MR-linac is feasible for SBRT (5 × 7 Gy) of pelvic lymph node oligometastases. The workflow allows full online planning based on daily anatomy.

Direct measurement of ion chamber correction factors, k and k , in a 7 MV MRI-linac.

The output of MRI-integrated photon therapy (MRgXT) devices is measured in terms of absorbed dose to water, D . Traditionally this is done with reference type ion chambers calibrated in a beam quality Q without magnetic field. To correct the ion chamber response for the application in the magnetic field, a factor needs to be applied that corrects for both beam quality Q and the presence of the magnetic field B, k .

Commissioning of a water calorimeter as a primary standard for absorbed dose to water in magnetic fields.

MRI guided radiotherapy devices are currently in clinical use. Detector responses are affected by the magnetic field and need to be characterized in terms of absorbed dose to water, D , against primary standards under these conditions. The aim of this study was to commission a water calorimeter, accepted as the Dutch national standard for D in MV photons and to validate its claimed standard uncertainty of 0.

Volumetric modulated arc therapy for total body irradiation: A feasibility study using Pinnacle treatment planning system and Elekta Agility™ linac.

A study was undertaken to explore the use of volumetric modulated arc therapy (VMAT) for total body irradiation (TBI). Five patient plans were created in Pinnacle using nine 6 MV photon dynamic arcs. A dose of 12 Gy in six fractions was prescribed.

Verification of junction dose between VMAT arcs of total body irradiation using a Sun Nuclear ArcCHECK phantom.

A volumetric modulated arc therapy (VMAT) approach to total body irradiation (TBI) has recently been introduced at our institution. The planning target volume (PTV) is divided into separate sub-volumes, each being treated with 2 arcs with their own isocentre. Pre-treatment quality assurance of beams is performed on a Sun Nuclear ArcCHECK diode array.

Changes to dose at surface and shifts of dose distributions at depth through dry and wet wound dressings for photon and electron beam radiotherapy.

Wound dressings are used during patient radiotherapy treatments, particularly in cases of radiation induced lesions. Potentially, the presence of a dressing may increase the dose to the skin, further aggravating the skin reaction and decrease the dose at depth. The changes are dependent on linear accelerator beam type and beam quality and were determined for 4 and 10 MV photon energies and 6 and 15 MeV electron energies using a slab phantom and fixed separation parallel plate chambers.