ACPSEM position paper: the safety of magnetic resonance imaging linear accelerators.

Magnetic Resonance Imaging linear-accelerator (MRI-linac) equipment has recently been introduced to multiple centres in Australia and New Zealand. MRI equipment creates hazards for staff, patients and others in the MR environment; these hazards must be well understood, and risks managed by a system of environmental controls, written procedures and a trained workforce. While MRI-linac hazards are similar to the diagnostic paradigm, the equipment, workforce and environment are sufficiently different that additional safety guidance is warranted. In 2019 the Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) formed the Magnetic Resonance Imaging Linear-Accelerator Working Group (MRILWG) to support the safe clinical introduction and optimal use of MR-guided radiation therapy treatment units. This Position Paper is intended to provide safety guidance and education for Medical Physicists and others planning for and working with MRI-linac technology. This document summarises MRI-linac hazards and describes particular effects which arise from the combination of strong magnetic fields with an external radiation treatment beam. This document also provides guidance on safety governance and training, and recommends a system of hazard management tailored to the MRI-linac environment, ancillary equipment, and workforce.

The Modernization of Radiation Therapy Services in Cambodia: A Model of International Collaboration.

PURPOSE: Cambodia is a Southeast Asian low-middle-income country with a population of >15 million. In 2020, Cambodia was estimated to have 18,375 new diagnoses of cancer and 12,638 deaths attributable to cancer. Cambodia was estimated to have a deficit of 16 megavoltage machines in 2012. Cambodia's radiation therapy services have suffered through the tumultuous events of the country's history, with intermittent services until the last decade. In recent years, Cambodia has undergone rapid economic growth and, with this, the development of its first comprehensive cancer center, the National Cancer Centre (NCC). METHODS AND MATERIALS: Planning for NCC began in the early 2000s, with the aim to provide comprehensive care, including modern radiation therapy services, to the public. Funding for the center was supplied primarily by the Cambodian government, assisted by donations from partners including the International Atomic Energy Agency. Training collaborations were formed with international partners, including the Asia-Pacific Radiation Oncology Special Interest Group (APROSIG) of the Royal Australian and New Zealand College of Radiologists and the Asia-Pacific Special Interest Group (APSIG) of the Australasian College of Physical Scientists and Engineers in Medicine. RESULTS: The main model of APROSIG/APSIG collaboration has been in-country training, including the posting of an Australian medical physicist and radiation therapist in Phnom Penh for a year's duration to oversee a safe and sustainable start to the radiation therapy program. The first linear accelerator patient was treated at NCC in March 2018 and the first brachytherapy patient in September 2018. Since that time, the department has treated to capacity, with very little machine downtime. NCC provides comprehensive cancer services including medical oncology, pediatric oncology, hematology, palliative care, surgical oncology, and nuclear medicine. Several challenges to expanding radiation therapy services currently exist, including human resources and cultural stigma. CONCLUSION: Despite many decades of tragedy and suffering, Cambodia serves as an example of successful implementation of modern radiation therapy in a low- and middle-income country. The keys to success have included local champions, support of the Ministry of Health, and willingness to embrace collaboration. The pandemic brings yet another challenge to cancer control in Cambodia, and novel training platforms are being explored.

Implementation of 3D conformal radiotherapy technology at the National Cancer Centre Mongolia: A successful Asia-Pacific collaborative initiative.

INTRODUCTION: Mongolia has a population of 3.3 million and is classified by the WHO as a lower middle-income country. Cancer is now a major public health issue and one of the leading causes of mortality. Within the framework of an existing national cancer control plan, the National Cancer Centre of Mongolia (NCCM) aimed to implement 3D conformal radiation planning and linac-based treatment delivery. METHODS: In 2018, an opportunity arose for collaboration between the Mongolia Society for Radiation Oncology (MOSTRO), the National Cancer Centre Mongolia (NCCM), the Asia-Pacific Radiation Oncology Special Interest Group (APROSIG) of the Royal Australian and New Zealand College of Radiologists (RANZCR) and the Asia-Pacific Special Interest Group (APSIG) of the Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) and radiation therapists (RTTs) from a range of Australian centres. We describe here the results to date of this collaboration. RESULTS: Despite a number of significant technical and practical barriers, successful linac commissioning was achieved in 2019. Key factors for success included a leadership receptive to change management, stable bureaucracy and health systems, as well as a synchronised effort, regional cooperation and mentorship. CONCLUSION: Future directions for ongoing collaborative efforts include a continued focus on education, practical training in radiotherapy planning and delivery and postgraduate education initiatives. Radiotherapy safety and quality assurance remain an ongoing priority, particularly as technological advances are sequentially implemented.

High dose rate brachytherapy source measurement intercomparison.

This work presents a comparison of air kerma rate (AKR) measurements performed by multiple radiotherapy centres for a single HDR 192Ir source. Two separate groups (consisting of 15 centres) performed AKR measurements at one of two host centres in Australia. Each group travelled to one of the host centres and measured the AKR of a single 192Ir source using their own equipment and local protocols. Results were compared to the 192Ir source calibration certificate provided by the manufacturer by means of a ratio of measured to certified AKR. The comparisons showed remarkably consistent results with the maximum deviation in measurement from the decay-corrected source certificate value being 1.1%. The maximum percentage difference between any two measurements was less than 2%. The comparisons demonstrated the consistency of well-chambers used for 192Ir AKR measurements in Australia, despite the lack of a local calibration service, and served as a valuable focal point for the exchange of ideas and dosimetry methods.