Just-in-Time Quality Assurance Auditing of Radiotherapy Control Informatics

Article Outline

• Purpose/Objective
• Materials/Methods
• Results
• Conclusions
• Copyright

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Purpose/Objective 

To investigate the feasibility of using real-time network monitoring through passive wiretapping or “packet sniffing,” as a technique to double-check critical control data being transferred between computers immediately prior to treatment, in order to reduce the probability of informatics-related misadministration by linear accelerator systems.

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Materials/Methods 

A laboratory prototype system has been developed, consisting of an ordinary Pentium 4 workstation running Linux, connected to the clinical network and configured to passively observe all network traffic that enters or exits the therapists' linac control computer. Analysis of the Varis 7 network traffic ensuing from clicking “Open Patient” at the control computer yielded knowledge of the network transfer protocols of critical clinical data, such as IMRT leaf sequence definitions. The system was subsequently programmed to automatically extract clinical information from the packet stream, and save this human-readable information to a custom database.

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Results 

Upon execution of the “Open Patient” command at the therapists' control computer, the system automatically detects, extracts, and saves the patient, field, and MLC configuration data embedded in the data packet exchange between the linac control computer and the clinical database server. By saving this detected data to a custom database, a vendor-independent archive of transmitted control data is established. The (per-fraction) processing time to accomplish this is under one second. The entire process is transparent to the clinical computers under observation and does not modify the clinical packet stream.

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Conclusions 

This system establishes the technical feasibility of using passive network wiretapping as a quality assurance tool for radiation oncology informatics. Based on these initial successes, an upgraded clinical prototype system, designed for dependability and therapist ease-of-use, is under development. By comparing just-transmitted treatment data against data from the patient's previous fractions, the clinical prototype provides vendor-independent, per-fraction verification of treatment informatics, thus informing clinicians of modified or corrupt treatment data minutes before turning the beam on.