ESTRO 2020 Abstract book

S230 ESTRO 2020

SP-0396 Novel approaches to auditing J. Lehmann 1 1 Calvary Mater Newcastle, Department Of Radiation Oncology, Newcastle- Nsw, Australia Abstract text Modern radiation therapy requires novel approaches to auditing. As new treatment technology and techniques are being introduced constantly, new audits are needed. The fast pace of change calls for an equally increased pace of audit development or adoption as well as for a fast audit turnaround for a potentially large number of facilities. Ever shrinking budgets necessitate lower audit costs. Additionally, large distances between audited facilities in some jurisdictions as well as the global nature of clinical trials compel new thinking towards dosimetry audits. Phantom based audits have a proven track record and will remain essential for end to end tests. Likewise, onsite audits with expert personnel present generally enable the most accurate measurements. They also allow for immediate discussion of any found problems and thereby a fast return to optimal patient care. Significant experience exists with postal audits, where phantoms with detectors are shipped to the audited facility, irradiated and shipped back for analysis. Advancing remote auditing, electronic portal imaging device based audits that do not use a physical phantom have been introduced recently. The audits are accurate and comprehensive in assessing intensity modulated treatments. Not requiring the shipment of any equipment these audits are less expensive and faster accessible as well as more environmentally friendly. Not depending on the availability of phantoms many facilities can perform the audit measurements in parallel and upload their calculations and measurements (images) for central processing and analysis. Similarly, the use of log file analysis in remote audits has been investigated and implemented. A new audit concept is the assessment of the sensitivity of patient specific quality assurance (PSQA) tools. Such audit checks whether a facility’s clinical PSQA can find treatment delivery errors. Small errors are introduced into a series of plan delivery files, which the facility is asked to perform their PSQA on. These audits, which are also delivered remotely, expand the scope of dosimetry auditing to a new level. Novel approaches to auditing supplement existing audits. They thereby help ensure safe delivery of modern radiation therapy and meaningful results in clinical trials.

Debate: This house believes that RTTs will be leading ALL decision making in real-time adaptive radiation therapy in the future

SP-0397 For the motion L. Wiersema 1 1 Netherlands Cancer Institute, radiotherapy, Amsterdam, The Netherlands Abstract text 2020 is the beginning of a new era for real‐time adaptive radiation therapy. The first clinical implementations of real‐time adaptive techniques are behind us and will become mainstream treatment in the future for conventional and MRI‐guided treatments. RTTs have often been part of the implementation of new technologies, it is important to include the RTTs in developing the guidelines for this new workflow as they are leading on the treatment machines and closely involved with patients’ needs. Many departments are challenged with limited time, especially for radiation oncologists. Real‐time adaption will take more time for each fraction. With good guidelines this entire workflow could be led by RTTs. In many institutes RTTs are already involved in soft‐tissue assessment, (deformable) registration and delineation of organs at risk, together with the radiation oncologists this could be taken to the next level. As we would like to help as many patients as we do now, a redistribution of tasks to RTTs is needed, training and lots of practice is important, let’s start today! SP-0398 Against the motion C. Eccles 1 1 The Christie, Radiotherapy, Manchester, United Kingdom Abstract text In the era of on‐line adaptive radiotherapy, the entire process of pre‐treatment imaging, planning, QA and delivery is compressed into the duration of a single (albeit lengthened) radiotherapy appointment and is repeated throughout the course of radiotherapy. In conventional radiotherapy, the preparation phase alone can take 2 days to 2 weeks with multi‐disciplinary input, and requires only very simple on‐line decisions/interventions to be made. So why, if this process that normally requires input from RTTs, Oncologists, and Physicists, when compressed into the timescale of a single fraction and requiring complex real‐time decisions/interventions (and associated skills) should it be that the entire MDT is not required? This shortened timeframe and increased complexity would surely heighten the anxiety and/or risk of errors by leaving all real‐time decisions up to the RTTs. Instead of reducing the number of highly skilled professionals in the control area, perhaps we should limit the implementation of online adaptive radiotherapy to institutions with the resources to hire more highly qualified professionals to deliver on‐line adaptive radiotherapy collaboratively? Or perhaps the solution is to implement robust AI (and associated QA) to remove the humanized decision making processes from online adaptive radiotherapy completely? This house would argue that infinite resources or fully developed AI technologies are required for on‐line decision making in adaptive radiotherapy.