ESTRO 2020 Abstract book

S142 ESTRO 2020

be summarized, and possible benefits of MR-guided adaptive treatment for oligometastases will be discussed.

methods and identify common simplifications. Finally, we will explore the performance of one certain example of a deterministic RTE solver. The second part of the lecture will cover the issue of reporting dose-to-water vs. dose-to- medium. We will review how this is done in different treatment planning systems, explain the differences, and discuss the conversion between the two methods.

Teaching Lecture: Bladder conservation strategies

SP-0248 Bladder preservation strategies A. Choudhury 1 1 The Christie NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom Abstract text It is becoming increasingly accepted that bladder preservation is comparable to cystectomy when treating muscle-invasive bladder cancer with curative intent. There are a number of different strategies involving systemic radiosensitisers, hypoxia modification, hyperthermia and brachytherapy to name a few. Although there are various strategies available, a predictive biomarker that can be used to stratify patients for their optimal treatment remains elusive. SP-0249 Radiosurgery: potentials and pitfalls D. Eaton 1 1 Guy's and St Thomas' NHS Foundation Trust, Medical Physics, LONDON, United Kingdom Abstract text Stereotactic radiosurgery (SRS) allows the delivery of highly conformal radiotherapy, usually in a single high dose fraction, with high positional accuracy, to a range of malignant and benign lesions in the brain. Various technologies have evolved to deliver SRS, including Gamma Knife, CyberKnife and fixed cone or MLC arc-based linac solutions. However, the philosophy used in SRS is often different to other forms of radiotherapy, and can cause confusion when comparing treatment plans or clinical studies. For example, the dose prescriptions, use of margins and uncertainties can easily be lost in translation. This lecture aims to review the approaches taken in SRS, some of the recent advances in treatment delivery and some of the pitfalls which the clinical physicist should be aware of when considering these treatments. Teaching Lecture: Radiosurgery: potential and pitfalls

Teaching Lecture: Patient empowerment in radiotherapy

SP-0251 Patient empowerment in radiotherapy H. Bulbeck 1 1 Brainstrust - the brain cancer people, policy, Cowes, United Kingdom Abstract text When diagnosed with cancer, people cycle through the emotions of fear, anxiety, sadness, anger. The reaction is unguarded and visceral. Inevitably the values and beliefs that have made us the person we are come into question – our sense of identity and purpose, and our relationship to those around us. This presentation explores the complexity of challenges that come into play and which are front of mind when thinking about treatment, specifically radiotherapy. It describes what is important to the patient and their caregivers, where this concords and where it divides and how to talk about it. It describes where perceptions about radiotherapy come from, how accurate these are and what information patients need when thinking about treatment choices. It will look specifically at the role of patient voice in radiotherapy research, through the work of public and patient involvement with the Clinical and Translation Radiotherapy Working Group (CTRad). Patient and Public Involvement (PPI) is a particular strength and priority of CTRad; it is integral to, and has a key role, in all five pillars of CTRad’s strategic vision[1]: 1) Evaluating and implementing technological advances 2) Converting discovery science into patient benefit 3) Building the radiotherapy research workforce 4) Integrating radiotherapy into precision medicine 5) Changing practice through a portfolio of innovative and collaborative clinical trials. Our ambition is that CTRad consumers will be able to tell their stories clearly and fluently. These stories will reflect an active partnership between the public and researchers. This will ensure that: · research has relevance and asks the right questions · outcome measures are acceptable and appropriate and measure what is important to patients and their families · treatments are not duly onerous for participants · better information is provided, enhancing recruitment to trials and retention · the patient perspective is considered in planning, developing, delivering studies and interpreting findings · results are disseminated more effectively to public audiences · consumer involvement is routinely incorporated in grants, trial management and other outputs. This talk will explore how we work in partnership with the radiotherapy research community to improve patient experience and increase PPI activity in radiotherapy research. Involvement must occur across all levels including policy creation, project development, planning and delivery. This requires active engagement and involvement by informing, consulting and working

Teaching Lecture: Dose calculation in external beam radiotherapy: Solution of the Boltzmann transport equations and dose to water vs dose to medium issues

SP-0250 Dose calculation in external beam radiotherapy: The radiation transport equation and dose-to-water vs. dose-to-medium issues C. Ceberg 1 1 Lund University, Medical Radiation Physics, Lund, Sweden Abstract text In the first part of this teaching lecture on dose calculations in external beam radiotherapy, we will formulate the radiation transport equation (RTE) and describe its different components. Step-by-step, we will then walk through the solution using deterministic