Commissioning a standalone adaptive radiotherapy linac in a multi-vendor environment

Current radiotherapy machines intended to perform streamlined online adaptive therapy are designed to be standalone, which makes it challenging to integrate them with the rest of the clinic. This work describes the installation of a standalone CT-guided online adaptive system, the Varian Ethos, in a busy clinic utilizing products from multiple vendors, including RayStation as the treatment planning system (TPS) and MOSAIQ as the oncology information system (OIS). The aim was to develop solutions that minimized workload increases for staff using redundant systems and to implement this new technology safely, with no increase in safety reports resulting from its integration into the clinic. The Ethos was delivered with a pre-configured beam model, and a separate Ethos beam model was developed in RayStation 10A. Non-adaptive treatments were planned in RayStation and transferred to Ethos for delivery. Although MOSAIQ 2.64 could not communicate with the Ethos, a machine characterization file was developed to allow manual recording of the treatment fields in MOSAIQ. Online adaptive therapy was performed using the Ethos TPS and OIS with documentation in MOSAIQ. Although dose calculations of the same plans differed by 1%-2% in the pelvis in RayStation compared to the Ethos TPS, dose computed in both systems passed measurement-based QA, end-to-end testing, and clinical trial credentialing, so both systems were commissioned for clinical use. RayStation plans were successfully modified for delivery on Ethos, and at go-live, all non-adaptive planning was performed in RayStation and adaptive planning in Ethos. Ethos treatments were documented in MOSIAQ, which remained the OIS of record for all patients. Monitoring of error reports indicated some unique failure modes to the new technology, but the overall number of safety reports remained comparable to other systems. In conclusion, Ethos was successfully deployed for both non-adaptive and online adaptive therapy in a multi-vendor environment.