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Session: Proton Therapy II [Return to Session]

Integrating Ethos Adaptive Radiotherapy in a Multi-Vendor Environment: First Clinical Experience

J Pursley*, C Foote, D McClatchy, S Yan, D Gierga, Massachusetts General Hospital and Harvard Medical School, Boston, MA


TU-D1030-IePD-F7-3 (Tuesday, 7/12/2022) 10:30 AM - 11:00 AM [Eastern Time (GMT-4)]

Exhibit Hall | Forum 7

Purpose: Varian Ethos is a standalone radiotherapy system streamlined to efficiently perform online adaptive therapy. Because it is standalone, there are many challenges in integrating this system in a busy multi-vendor clinic. We present strategies for overcoming these challenges at the first site to install Ethos without a Varian ARIA record & verify (R&V) system.

Methods: An Ethos system was installed in a photon clinic with a mix of Varian and Elekta linacs, MOSAIQ R&V (Elekta), RayStation 10A treatment planning (RaySearch Laboratories), Radcalc (LAP) and Mobius (Varian) for quality assurance, and an in-house whiteboard system for patient task tracking. An Eclipse workstation was also installed to act as the Aria server connection required for Ethos. A 6MV FFF beam model for Ethos was created and commissioned in RayStation. Workflows were developed with the assistance of a Systems-Theoretic Process Analysis (STPA), using a mix of new and existing technology to enable both adaptive and non-adaptive treatments on Ethos in a MOSAIQ R&V environment.

Results: The STPA highlighted that manual data transfer between systems could lead to many potential unsafe control actions. Accordingly, Ethos implementation included automating data transfer between each system to the extent possible. Using scripting and in-house tools, a streamlined process for Ethos treatment planning, delivery, and QA was developed to mirror as closely as possible the clinical workflow for other machines. Staff were provided with training in the new procedures, and that training was reinforced through the first few weeks of patient treatments, leading to a successful rollout of adaptive and non-adaptive treatments on Ethos.

Conclusion: Due to the standalone nature of the Ethos system, duplicate work in multiple systems is unavoidable even in a single-vendor environment. We demonstrated that with proper control systems Ethos may also be successfully implemented in a multi-vendor environment.

Funding Support, Disclosures, and Conflict of Interest: Massachusetts General Hospital has a product evaluation agreement with Varian to evaluate Ethos in a non-standard information systems environment. Susu Yan has a research agreement with RaySearch Laboratories for proton treatment planning and RayIntelligence.


Commissioning, Quality Control


TH- External Beam- Photons: adaptive therapy

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