The Impact of Technological Changes on Radiation Therapy Incidents

Article Outline

• Purpose/Objective(s)
• Materials/Methods
• Results
• Conclusions
• Copyright

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Purpose/Objective(s) 

To examine incident rates in the external beam radiation therapy (RT) process as significant changes in technology were introduced in a busy clinic.

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Materials/Methods 

From 2001 to 2006, the Princess Margaret Hospital had undergone several technological and practice enhancements, including 14 accelerator replacements and upgrades, changing the treatment planning software, widespread implementation of IMRT, documentation of standard treatment protocols, implementation of 4DCT, encouraging the reporting of incidents and near misses in a blame-free environment, and widespread use of cone-beam CT guided RT. All treatment incidents, including near misses starting in 2004, were analyzed under a research ethics board approval. Since the description of each incident or near miss is unique, we have developed a taxonomy, based on our review, to classify each reported incident according to the type (prescription or geometry), cause (location, documentation, non-compliance, laterality, prescribed change, human error, planning/dosimetry, software/hardware malfunction, accessory), and clinical impact (none, minor, moderate, severe) of each incident. Furthermore, each report has identified what stage of a generalized external beam radiation therapy process (booking, scanning, planning, review, and treatment) the incident or near-miss event occurred.

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Results 

872 incident and near-miss reports were analyzed over this six year period. The average incident rate per RT course was 1.7 ± 0.4%, with a majority of errors related to prescription issues. Excluding near misses, the incident rate fell to 1.4 ± 0.3%. Both rates showed a downward trend following an increase as the RT program underwent significant technological and procedural changes. An average of 0.33 severe error per year was observed. Over the course of six years and several technological changes, decreases in the occurrence of events due to wedges or other accessories (59 to 15), prescribed changes to treatment parameters (41 to 13), non-compliance to treatment protocols (12 to 7), and location (32 to 18) have decreased, while documentation-related incidents have risen (2 to 30). Throughout the review period, the proportion of incidents is highest at the planning and treatment stages, and incidents with the highest impact occurring at the latter stage.

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Conclusions 

A new taxonomy has helped analyze systematically all incident reports in our clinic. The database has helped guide the allocation of limited QA resources. The incident rate at our clinic has stabilized at our clinic over several technological and process changes, but has remained low. Trends in radiation therapy treatment incidents in a clinic that has undergone significant changes in technology and processes has been assessed, indicating robustness of our practice in view of these changes.