The impact of advanced technologies on treatment deviations in radiation treatment delivery

To assess the impact of new technologies on deviation rates in radiation therapy (RT).

Treatment delivery deviations in RT were prospectively monitored during a time of technology upgrade. In January 2003, our department had three accelerators, none with "modern" technologies (e.g., without multileaf collimators [MLC]). In 2003 to 2004, we upgraded to five new accelerators, four with MLC, and associated advanced capabilities. The deviation rates among patients treated on "high-technology" versus "low-technology" machines (defined as those with vs. without MLC) were compared over time using the two-tailed Fisher's exact test.

In 2003, there was no significant difference between the deviation rate in the "high-technology" versus "low-technology" groups (0.16% vs. 0.11%, p = 0.45). In 2005 to 2006, the deviation rate for the "high-technology" groups was lower than the "low-technology" (0.083% vs. 0.21%, p = 0.009). This difference was caused by a decline in deviations on the "high-technology" machines over time (p = 0.053), as well as an unexpected trend toward an increase in deviations over time on the "low-technology" machines (p = 0.15).

Advances in RT delivery systems appear to reduce the rate of treatment deviations. Deviation rates on "high-technology" machines with MLC decline over time, suggesting a learning curve after the introduction of new technologies. Associated with the adoption of "high-technology" was an unexpected increase in the deviation rate with "low-technology" approaches, which may reflect an over-reliance on tools inherent to "high-technology" machines. With the introduction of new technologies, continued diligence is needed to ensure that staff remain proficient with "low-technology" approaches.