Application of repeat image analysis to radiation therapy imaging modalities as a quality improvement tool for image guided radiotherapy.

Background: Repeat images contribute to excess patient dose and workflow inefficiencies and can be analyzed to identify potential areas for improvement within a program. Although routinely used in diagnostic imaging, repeat image analysis is not widely used in radiation therapy imaging, despite the role of imaging in the delivery of precise radiation treatments.

Purpose: Repeat image analysis was performed for on-board cone beam CT imagers and CT simulators within a radiation therapy department.

The impact of COVID-19 workflow changes on radiation oncology incident reporting.

Background: The Ottawa Hospital's Radiation Oncology program maintains the Incident Learning System (ILS)-a quality assurance program that consists of report submissions of errors and near misses arising from all major domains of radiation. In March 2020, the department adopted workflow changes to optimize patient and provider safety during the COVID-19 pandemic.

Purpose: In this study, we analyzed the number and type of ILS submissions pre- and postpandemic precautions to assess the impact of COVID-19-related workflow changes.

Development of a Curriculum for the Implementation of Stereotactic Radiation Therapy Programs in Middle-Income Countries.

Purpose: The aim of this work was to develop a curriculum to be used in the implementation of stereotactic radiation therapy programs in middle-income countries. The curriculum needed to be scalable and flexible to be easily adapted to local situations.

Methods: The curriculum was developed through a partnership between multidisciplinary teams from established clinics in both middle-income and high-income countries.

Contamination Resulting From a Broken 125I Seed During a Brachytherapy Procedure.

Brachytherapy programs within radiation therapy departments are subject to stringent radiation safety requirements in order to ensure the safety of the staff and patients. Training programs often include brachytherapy-specific radiation safety training modules that address the specific risks associated with radioactive sources, emergency procedures, and regulatory requirements specific to the use of radioisotopes. Unlike other uses of radioactive materials, brachytherapy uses sealed sources and therefore under routine operations does not encounter radioactive contaminants.

Survey of patient-specific quality assurance practice for IMRT and VMAT.

A first-time survey across 15 cancer centers in Ontario, Canada, on the current practice of patient-specific quality assurance (PSQA) for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) delivery was conducted. The objectives were to assess the current state of PSQA practice, identify areas for potential improvement, and facilitate the continued improvement in standardization, consistency, efficacy, and efficiency of PSQA regionally. The survey asked 40 questions related to PSQA practice for IMRT/VMAT delivery.

Improved X-Ray Safety, Quality Control, and Resource Management in Medical Imaging Using QATrack.

Introduction/background: Management of a quality assurance program in diagnostic imaging involves a variety of machine types, multiple vendors, and a large number of frontline staff who have different specializations. Standardizing tests across multiple platforms in the face of vendor recommendations, regulatory requirements, and professional practice protocols can present challenges to maintain a robust and coherent quality assurance program. The current work presents a unique application of an existing tool that can be used to manage a comprehensive quality assurance program in a diagnostic imaging department.

Streamlining Regulatory Activities Within Radiation Therapy Departments Using QATrack.

Radiation therapy departments are faced with the challenge of tracking numerous quality control tests as well as monitoring service events affecting radiation therapy treatment units. Service events, in particular, pose a challenge since the clinic must be able to provide evidence to the regulatory body that both the service work and any required follow-up tests were recorded and authorized by the appropriate staff. This article presents an integrated approach to tracking quality control tests and service event logs using QATrack+.

Wall correction factors, Pwall, for parallel-plate ionization chambers.

The EGSnrc Monte Carlo user-code CSnrc is used to calculate wall correction factors, Pwall,, for parallel-plate ionization chambers in photon and electron beams. A set of Pwall values, computed at the reference depth in water, is presented for several commonly used parallel-plate chambers. These values differ from the standard assumption of unity used by dosimetry protocols by up to 1.

Wall correction factors, Pwall, for thimble ionization chambers.

The EGSnrc Monte Carlo user-code CSnrc is used to calculate wall correction factors, Pwall, for thimble ionization chambers in photon and electron beams. CSnrc calculated values of Pwall give closer agreement with previous experimental results than do the values from the standard formalism used in current dosimetry protocols. A set of Pwall values, computed at the reference depth in water, is presented for several commonly used thimble chambers.

CSnrc: correlated sampling Monte Carlo calculations using EGSnrc.

CSnrc, a new user-code for the EGSnrc Monte Carlo system is described. This user-code improves the efficiency when calculating ratios of doses from similar geometries. It uses a correlated sampling variance reduction technique.

An EGSnrc investigation of cavity theory for ion chambers measuring air kerma.

The EGSnrc system is used to compare the response of an aluminum-walled thimble chamber to that of a graphite-walled thimble chamber for a 60Co beam. When compared to previous experimental results, the EGSnrc values of the ratios of chamber response differ by as much as 0.7% from the experiment.