ESTRO 2024 - Abstract Book

S5514

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

1108

Proffered Paper

Support system in an RTT-only Conebeam CT-guided online adaptive radiotherapy workflow

Karin Goudschaal 1 , Sana Azzarouali 1,2 , Jorrit Visser 1 , Laurien Daniels 1,2 , Duncan den Boer 1 , Arjan Bel 1

1 Amsterdam UMC, University of Amsterdam, Radiation Oncology, Amsterdam, Netherlands. 2 Cancer Center Amsterdam, Cancer Therapy, Treatment and Quality of Life, Amsterdam, Netherlands

Purpose/Objective:

Daily online adaptive radiotherapy (oART) leads to a redistribution of tasks and roles during the online fractions, especially in a Radiation Therapist (RTT)-only workflow. Adapting the daily Gross Tumor Volume (GTV) and Organs-At Risk (OARs) as well as (initial) evaluation of the daily treatment plan are such tasks, delegated from Radiation Oncologist (RO) and Medical Physics Expert (MPE). An RTT-only workflow, after tasks are delegated, requires a reliable online and offline support system [1]. A support system developed and maintained by a multidisciplinary team supports clinical decision-making. The aim of this work was to set up a support system in an RTT-only CBCT guided oART workflow in terms of target and OAR delineation, target and OAR coverage and dosimetry.

Material/Methods:

At the Amsterdam UMC six ring-based linacs integrated with CBCT and software platform for treatment planning and delivery (Ethos Therapy™, version 1.1, Varian a Siemens Healthineers Company, USA) were installed divided over three locations, starting in 2020. RTTs were trained in an online Ethos test environment (Emulator, version 1.1, Varian a Siemens Healthineers company, USA). The training included target and OARs definition, practicing GTV, CTV and OARs delineation and performing oART in the Emulator. Bladder [2], rectum [3] and breast cancer patients were treated in a first stage with a dedicated multidisciplinary team present during all fractions. In a second stage, i.e. the RTT-only workflow, the RO and MPE were available on-call (to consult remote or live). Prior to each patient’s first fraction, a multidisciplinary briefing was held with RO, MPE and RTTs, during which patient specific details regarding target volume and treatment planning were discussed. For the fractions to be treated, specific oART workflow details were recorded according to a fixed lay-out for a rotating RTT-team in the oncology information system (OIS). The RO and MPE remained present during the first fraction. Online support consisted of a traffic light protocol [4]. Because cancer patients were treated in the RTT-only workflow from three locations an online support system sharing the Ethos Therapy™ screen with videoconferencing (Teams, Microsoft, USA) was arranged in a view-only modus. RO and MPE were on-call with videoconferencing in the event of a “red” traffic light.