A "quality-control-based correction method" for displayed dose indices on CT scanner consoles in patient dose surveys

作者：Parsi Masoumeh; Sohrabi Mehdi^*; Mianji Fereidoun; Paydar Reza

来源：Physica Medica, 2017, 38: 88-92.

DOI：10.1016/j.ejmp.2017.05.054

• Diagnostic reference level
• Computed Tomography
• Quality control
• CT dose survey

Purpose: A new quality-control-based (QC-based) method is introduced to obtain correction factors to be applied to displayed patient dose indices (CTDIVol and DLP) on CT scanner consoles to verify improvement of dose surveys for diagnostic reference levels (DRLs) determination.
Method: An available data-base of QC documents and reports of 57 CT scanners in Tehran, Iran was used to estimate CTDIVol, DLP and relevant correction factors for three CT examination types including head, chest and abdomen/pelvis. The correction factor is the ratio of QC-based estimated dose to displayed dose. A dose survey was performed by applying on-site "data collection method" and correction factors obtained in order to select CT scanners in three modes for determination of CT DRLs by inclusion of: (a) all CT scanners before displayed dose indices were corrected (57), (b) only CT scanners calibrated by QC experts (41) and (c) all CT scanners after displayed dose indices were corrected (57).
Results: For the 41 CT scanners, correction factors of three examination types obtained in this study are within the acceptance tolerance of IAEA HHS-19. The correction factors range from 0.45 to 1.7 (average of 3 examinations) which is due to the change in the calibrated value of CTDIVol over extended time. The DRL differences in three modes are within +/- 1.0% for CTDIVol and +/- 12.4% for DLP.
Conclusions: The "QC-based correctio

• 出版日期2017-6