ESTRO 2022 - Abstract Book

S890

Abstract book

ESTRO 2022

In this study, participants reported a change in perceptions, increased knowledge, reduced anxiety, and greater understanding of the treatment process. A concerning result, is the lack of knowledge and understanding about RT among the ‘other’ health professionals that mange cancer patients, in particular the family doctor. Patients require their family doctor and other health professionals to be knowledgeable about RT to ensure patient centred care. An important next step to increase the patient access to RT may be to further explore the education of other health professionals about RT and promotion of the service.

Poster (digital): Other

PO-1055 Atrial fibrillation: worldwide preliminary data of LINAC-based STAR prospective phase II trial

F. Gregucci 1 , A. Di Monaco 2 , I. Bonaparte 1 , A. Surgo 1 , F. Troisi 2 , N. Vitulano 3 , F. Quadrini 4 , D. Di Molfetta 5 , G. Martinelli 5 , P. Guida 1 , R. Carbonara 1 , M.P. Ciliberti 1 , M. Grimaldi 2 , A. Fiorentino 1 1 Miulli General Regional Hospital, Radiation Oncology, Acquaviva delle Fonti - Bari, Italy; 2 Miulli General Regional Hospital, Cardiology, Acquaviva delle Fonti - Bari, Italy; 3 Miulli General Regional Hospital, Cardiology, Acquaviva delle Fonti -Bari, Italy; 4 Miulli General Regional Hospital Acquaviva delle Fonti - Bari, Cardiology, Acquaviva delle Fonti - Bari, Italy; 5 Miulli General Regional Hospital, Radiology, Acquaviva delle Fonti - Bari, Italy Purpose or Objective In elderly, paroxysmal atrial fibrillation (AF) is difficult to treat with drugs and catheter ablation due to the higher complication rate. Thus, non-invasive approaches should be favorite. Stereotactic arrhythmia radioablation (STAR) was used for ventricular tachycardia, but no data are available for LINear ACcelerator (Linac)-based STAR in AF patients. Based on this background, the aim of present study was to determine whether Linac-based STAR is considered safe for AF elderly patients. Materials and Methods The study was designed as a prospective phase-II trial started in May 2021 , conducted in a single, referral center (ClinicalTrials.gov: NCT04575662). The inclusion criteria were: patients aged over 70 years, with symptomatic paroxysmal AF; intolerance or non-response to anti-arrhythmic (ATT) drugs. The primary study endpoint was the 1-month post-STAR safety, as complete STAR delivery and no acute treatment-related adverse events more than G3, assessed according to the Common Terminology Criteria for Adverse Events (version 5.0). Secondary endpoints were: reductions in AF episodes and in AAT, overall survival. The sample size planning is 20 cases based on 95% success for the primary endpoint, with a significant level of 5% and a power of 90%. The date of the last follow-up was October 2021. All patients underwent to LINAC-STAR for a treatment dose of 25 Gy in 1 fraction to the area of the pulmonary veins. Results Here, the data of the first 4 worldwide patients treated were presented. All patients completed STAR, with an overall treatment time of 3 minutes. No acute treatment-related adverse events (>G1) at 1-month from procedure were registered. For 3 patients, with a median follow-up of 3 months, no acute side effects, no AF episodes and no AAT use, were reported. K. van Duren 1 , J. Veldman 1 , M. Parkes 1 , Z. van Kesteren 1 , M. Stevens 2 , J. van Schuppen 3 , G. van Tienhoven 1 , A. Bel 1 , I. van Dijk 1 1 Amsterdam UMC, Radiation Oncology, Amsterdam, The Netherlands; 2 Amsterdam UMC, Anaesthesiology, Amsterdam, The Netherlands; 3 Amsterdam UMC, Radiology, Amsterdam, The Netherlands Purpose or Objective Breathing motion causes substantial uncertainties in tumor position during radiotherapy. High frequency ventilation with small tidal volumes reduces the amplitude of breathing motion. The aim of this study was to quantify the motion of the right diaphragm dome in conscious healthy volunteers during non-invasive mechanical ventilation without percussion at various high frequency settings, using ultrasound. Materials and Methods Seven volunteers were mechanically ventilated with Positive End Expiratory Pressure (PEEP) at 60 breaths per minute (brpm) using a Hamilton-T1 ventilator, and at 60, 150, 250 and 400 brpm using a TwinStream jet-ventilator. During 40 s recordings, 900 consecutive sagittal images of the diaphragm were acquired using the bk3000 ultrasound system (BK Medical Benelux NV/SA, Mechelen, Belgium) with a convex ultrasound probe at 3.5 MHz and a temporal resolution of 23 frames per second. The same trained operator made all measurements. Measurements were undertaken in two separate sessions. The order of ventilation frequency settings for the TwinStream was randomized. The images from six volunteers of both measurement sessions and at all ventilation frequency settings were adequate and further analyzed semi-automatically in MATLAB (n=12). Excursions were determined based on a time motion image along the direction of movement near the anterior layer of the coronary ligament (Fig.1). From each time motion image, the diaphragm was segmented by thresh Conclusion The LINAC-based STAR could represent a valid alternative for elderly excluded from catheter ablation. PO-1056 Quantification of diaphragm motion with ultrasound during non-invasive high frequency ventilation