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A Patient Timeout System (PTS) Utilizing Delivery System Relay Interlocks for Pre-Treatment Patient Verification

D Barbee*, NYU Langone Health, New York, NY


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: ACR recommends performing patient timeouts before initiating treatment on a treatment delivery system, verifying a minimum of two forms of identification. Available patient verification systems are not standardized across platforms and frequently fail to provide hardstop interlocks and documented timestamps, resulting in workarounds or poor documentation. This work introduces a platform independent patient timeout system (PTS) that utilizes delivery system interlocks to provide a hardstop on patient timeout.

Methods: The PTS consists of a Raspberry Pi 4 (RPi) controlled relay wired into the delivery system relay junction box controlling a customer/spare interlock and a locally running .NET Windows application running at the operator station. When the relay is open no radiation can be delivered. The relay is controlled by RPi GPIO pins accessed by a locally running NodeJS webserver. The application interfaces with the RPi webserver via secure HTTPS request over local intranet. The application retrieves the currently moded-up patient from the record and verify system and requires therapist confirmation of (minimum 3): photo, name, date of birth, MRN, or treatment site before releasing the interlock. Two therapists sign off with institutional credentials to release the interlock with timeout information written to a database that will summarize all timeouts performed at course completion. Permissions for configuration, QA mode, and sign off are handled by Active Directory and permission servers.

Results: The PTS was successfully implemented on 5 Varian Truebeam installations across a hospital network. Required patient timeouts are now well-documented and included in the patient chart. Therapists have adapted well to the new workflow and appreciate the simplicity of the PTS.

Conclusion: A Patient Timeout System utilizing delivery system relays was developed and implemented, improving institutional safety by ensuring timeouts are performed. The system is vendor agnostic because hardware, not software, interfaces are utilized.


Quality Assurance, Quality Control, Validation


IM/TH- Formal Quality Management Tools: General (most aspects)

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