Room: AAPM ePoster Library
Purpose: To retrospectively review the monthly quality assurance (QA) results of the PET portion of a PET-CT simulator in the context of the newly published AAPM Task Group (TG) 174 report. To explore opportunities to optimize QA procedures.
Methods: PET portions of monthly QA procedures, test items, and action levels of a Siemens PET-CT simulator (Biograph mCT, Siemens Healthineers, Germany) in our department were reviewed in comparison to the recommendations of the newly published AAPM TG 174 report. The monthly QA results of past 9 years (2011-2019) were collected and analyzed with different tolerance levels. Quantification, uniformity, scatter and randoms correction, resolution, and PET and CT alignment tests were included in the analysis. For the QA results that were out of tolerance limit, further investigations were performed to identify contributing factors of suboptimal QA outcome.
Results: The recommended items for monthly PET QA in the TG report were fully included in our departmental QA procedure. The tolerance levels were either same or more stringent compared to TG 174 recommendations. Uniformity, scatter and randoms correction, resolution, and PET and CT alignment tests always passed our departmental and TG recommended tolerance levels. Quantification of standard uptake value (SUV) passed the TG recommendation (<15%) always but failed twice the departmental tolerance (<5%). Further investigation on the failing tests revealed that both incidents were caused by the variation in dose calibrator in the radioisotope dispenser, not due to the change in PET detector response.
Conclusion: The review of QA results showed very good consistency in the PET-CT scanner performance in terms of TG recommended monthly QA tests. The QA contents and procedures could be optimized in the future based on Failure Modes and Effects Analysis using the data provided from this study.