ESTRO 2024 - Abstract Book

S4185

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

Purpose/Objective:

Within a dedicated consortium, two clinical proton therapy (PT) centers collaborate with two industrial partners (PT system and treatment planning provider, respectively) to jointly develop, implement and evaluate an industrial solution for online-adaptive proton therapy (OAPT). This also requires a dedicated approach for patient-specific QA (pre- and post-treatment PSQA). As first step, we conducted a comprehensive assessment of the current clinical pre treatment PSQA protocols in the two clinical PT facilities. Furthermore, so-called “sanity checks” have been defined, which play a crucial role in the OAPT QA concept: First, they speed up and automate checks that are currently performed manually and second, in combination with secondary dose calculation, they provide additional trust/evidence that the treatment is safe and as expected, before the delivery is started.

Material/Methods:

The current PSQA workflows (from plan approval until delivery of first fraction, Fig. 1A) were systematically analyzed for both PT facilities. Center 1 employs the MOSAIQ (Elekta AB, SE) oncology information system (OIS) in combination with RayStation (RaySearch Laboratories, Stockholm, SE) as treatment planning system (TPS). Center 2 utilizes the RayCare OIS (RaySearch Laboratories, SE) in combination with RayStation. The two workflows are hereinafter referred to as “Separate-OIS” and “Integrated-OIS”, respectively. Time required for all human operations in these systems, including data preparation for phantom measurements and double checks was assessed via the number of required mouse clicks and manual entries. Sanity checks (SCs) are automated QA routines, aiming to replace manual checks carried out by the medical physics expert (MPE). They serve as an additional safety mechanism, which guarantees the plausibility of plan parameter adjustments induced by the adaptation process and verifies the integrity of transferred DICOM data. To achieve an OAPT-ready PSQA workflow while providing at least the same level of risk mitigation as the current protocol, we defined SCs for adapted treatment plans, based on existent QA procedures. We incorporated these features in a conceptual PSQA-workflow for OAPT (Fig. 1B), in which SCs are complemented by secondary dose calculation and log file-based QA to enable phantom-less PSQA. Furthermore, manual sub-processes in the current PSQA protocol, which are directly covered by SCs in the OAPT workflow were identified.