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CT Exam Alert Level Setting, Evaluation, and Case Examples

R Lamoureux*, D Sandoval, G Chambers, R Selwyn, University of New Mexico, Albuquerque, NM


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Dose monitoring for CT is a regulatory requirement with no true training or instruction on what to look for or how to trouble shoot when an exam comes through with a dose that is above the set alert level. This work aims to present how the alert levels are set at our institution, the evaluation process followed for each exam alert, as well as demonstrate some clinically encountered examples and the root cause analysis for dose increase.

Through the use of the dose tracking software, Radimetrics, global exam alert settings were created. These were set to alert for the 99th percentile per water equivalent diameter (WED) ranges. These ranges were modeled to match those set by Kanal et al for various body regions. For each exam that alerts, the exam is opened in our Philips® PACS system as well as in the Radimetrics dose tracking system. The tube current modulation plot provided in Radimetrics is analyzed and the images and topogram for each exam is analyzed for possible causes for variation/increases in dose.

Setting the limits per WED range allows for the capture of alerts for a variety of patient sizes. There are a few typical causes for alerts and through diligent review, each exam above the dose level can be accounted for. Through the discovery of new positioning issues, correlation to technologists that consistently have issues, or just new issues cropping up, root cause analysis allows us to detect, educate, and correct issues.

Reviewing dose alerts takes skill and effort and often results in new education for the technologist. Through sharing processes and results, perhaps this will become a slightly less cumbersome process and inspire a shared library of alert causes for reference.


CT, Diagnostic Radiology, Quality Control


IM- CT: Quality Control and Image Quality Assessment

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