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Poster - Thur Eve - 29: Detecting changes in IMRT QA using statistical process control
1Saskatoon Cancer Centre, Saskatoon SK.
Medical Physics
|May 19, 2017
Summary
Statistical process control (SPC) effectively identified changes in intensity-modulated radiation therapy (IMRT) quality assurance (QA) after a treatment planning system upgrade. SPC helps distinguish true process changes from random variation in IMRT QA results.
Area of Science:
- Medical Physics
- Radiation Oncology
- Quality Assurance
Background:
- Intensity-modulated radiation therapy (IMRT) quality assurance (QA) is critical for patient safety.
- Established tolerance limits for IMRT QA may not always reflect process control effectively.
- Treatment planning system (TPS) upgrades can potentially impact IMRT QA metrics.
Purpose of the Study:
- To evaluate the effectiveness of Statistical Process Control (SPC) methods in analyzing IMRT QA data.
- To determine if existing tolerance limits adequately indicate process control for IMRT QA.
- To assess the impact of a TPS upgrade on IMRT QA metrics using SPC.
Main Methods:
- Analysis of 239 measurement-based individual IMRT QA events for head and neck and prostate cancer cases.
- Application of SPC methods to assess process control before and after a TPS software upgrade (Eclipse v8.1.18 to v10.0.39).
- Comparison of SPC results with pre-defined tolerance limits for IMRT QA metrics.
Main Results:
- Initial tolerance limits were acceptable for 2 out of 3 metrics pre-TPS upgrade.
- Post-upgrade, SPC analysis indicated that initial limits were insufficient for process control in 2 out of 3 metrics.
- SPC successfully identified significant changes in IMRT QA results following the TPS upgrade.
Conclusions:
- SPC is a valuable tool for detecting changes and trends in IMRT QA processes.
- Routine SPC application can differentiate between random variation and actual process shifts in IMRT QA.
- Re-evaluation of tolerance limits may be necessary after significant system changes like TPS upgrades.
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