Evaluation of a deep learning magnetic resonance imaging reconstruction method for synthetic computed tomography generation in prostate radiotherapy.

Background And Purpose: In magnetic resonance imaging (MRI) only radiotherapy computed tomography (CT) is excluded. The method relies entirely on synthetic CT images generated from MRI. This study evaluates the compatibility of a commercial synthetic CT (sCT) with an accelerated commercial deep learning reconstruction (DLR) in MRI-only prostate radiotherapy.

Geometric impact and dose estimation of on-patient placement of a lightweight receiver coil in a clinical magnetic resonance imaging-only radiotherapy workflow for prostate cancer.

Background And Purpose: For pelvic magnetic resonance imaging (MRI)-only radiotherapy the use of receiver coil bridges (CB) is recommended to avoid deformation of the patient. Development in coil technology has enabled lightweight, flexible coils. In this work we evaluate the effects of a lightweight coil in a pelvic MRI-only radiotherapy workflow.

Control chart analysis of data from a multicenter monitor unit verification study.

Background And Purpose: This study aims to investigate the process of monitor unit verification using control charts. Control charts is a key tool within statistical process control (SPC), through which process characteristics can be visualized, usually chronologically with statistically determined limits.

Material And Methods: Our group has developed a monitor unit verification software that has been adopted at several Swedish institutions for pre-treatment verification of radiotherapy treatments.

A Monte Carlo study of a flattening filter-free linear accelerator verified with measurements.

A Monte Carlo model of an Elekta Precise linear accelerator has been built and verified by measured data for a 6 and 10 MV photon beam running with and without a flattening filter in the beam line. In this study the flattening filter was replaced with a 6 mm thick copper plate, provided by the linac vendor, in order to stabilize the beam. Several studies have shown that removal of the filter improves some properties of the photon beam, which could be beneficial for radiotherapy treatments.

Photon beam quality variations of a flattening filter free linear accelerator.

Purpose: Recently, there has been an increasing interest in operating conventional linear accelerators without a flattening filter. The aim of this study was to determine beam quality variations as a function of off-axis ray angle for unflattened beams. In addition, a comparison was made with the off-axis energy variation in flattened beams.

Dosimetric characteristics of 6 and 10MV unflattened photon beams.

Purpose: To determine dosimetric properties of unflattened megavoltage photon beams.

Materials And Methods: Dosimetric data including depth dose, profiles, output factors and phantom scatter factors from three different beam qualities provided by Elekta Precise linacs, operated with and without flattening filter were examined. Additional measurements of leaf transmission, leakage radiation and surface dose were performed.

Experimental investigation of the response of an a-Si EPID to an unflattened photon beam from an Elekta Precise linear accelerator.

The characteristics of an Elekta amorphous silicon (a-Si) electronic portal imaging device (EPID) in response to a 6 MV photon beam generated without a flattening filter, an unflattened beam, have been determined. The characteristics were then compared to those for a conventional photon beam generated with a flattening filter in the beam, a flattened beam, in order to determine the suitability of an a-Si EPID for transit dosimetry. The response of the EPID to the unflattened beam increased by 7.