ESTRO 2024 - Abstract Book

S5773

RTT - Education, training, advanced practice and role developments

ESTRO 2024

1344

Poster Discussion

Implementation of RTT-led OAR delineation training for pancreatic SABR on the MR Linac

Mairead Daly 1 , Brocklehurst Andrew 2 , Benedict Dobby 3 , Claire Nelder 3 , James Tallon 3 , Lisa McDaid 3 , Ananya Choudhury 2,1 , McWilliam Alan 1,4 , Ganesh Radhakrishna 2 , Cynthia L Eccles 3,1 1 University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom. 2 The Christie Hospitals NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom. 3 The Christie Hospitals NHS Foundation Trust, Radiotherapy, Manchester, United Kingdom. 4 The Christie Hospitals NHS Foundation Trust, Medical Physics & Engineering, Manchester, United Kingdom

Purpose/Objective:

In 2022 online adaptive stereotactic ablative body radiotherapy (SABR) for pancreatic cancer on the magnetic resonance linear accelerator (MR Linac) was implemented in our institution using a multidisciplinary workflow. ‘Clinician-lite’ or RTT-led delineation have been successfully implemented on the MR Linac for other sites (i.e., bladder, prostate) so we developed a similar strategy for RTT-led OAR delineation for pancreatic SABR, with the aim of leveraging RTTs existing skills to integrate a ‘clinician-lite’ approach in the future. Here, we present our training framework to facilitate RTT-led OAR delineation training in a single institution.

Material/Methods:

Adaptive online pancreatic SABR at our institution was initially implemented in 2022 using a multidisciplinary workflow. In brief this, is: using the adapt to shape (ATS) workflow, OARs are deformably propagated from the reference magnetic resonance image (MRI) to initial treatment MRI, and the target, including a 2cm expansion around this, are rigidly propagated. Only OAR within the 2cm expansion are re-delineated on a daily basis, and initially all delineation was done by the oncologist (RO). Daily online ATS is resource-intensive, requiring radiographers (RTTs), physicists and the RO present for the whole fraction (mean duration 1h15m). to move to a clinician-lite strategy, a multi-stage approach was developed after training of a ‘trainer RTT’ by an RO. The training programme, which followed our established training framework is presented in Figure 1. Briefly, an initial didactic abdominal anatomy session was delivered by the ‘trainer RTT’, as well as provision of online resources and consensus guidelines. Offline, RTTs delineated abdominal OAR including liver, stomach, duodenum, small and large bowel, throughout a typical abdominal scan volume for 1 case. Scans were balanced fast field echo (bFFE) 3D VANE MRI scans were acquired on the PRIMER imaging study (NCT02973828) using an abdominal compression belt. These OAR were peer-reviewed by the trainer RTT prior to completion of further cases. A training session with the RO, including discussion of considerations for OAR and peer review of a selection of remaining cases was then carried out. Following this, RTT’s re-delineated all cases with a gap of >4 weeks between repeat and initial, in a 6cm expansion around the head of pancreas only, to simulate the OAR likely to require re-delineation online.

Results: