Program Information
Machine Setting and Phantom Dependencies On Objective Measurement of Ultrasound System Sensitivity
Z Li*, C Brunnquell , J Zagzebski , University of Wisconsin, Madison, WI
Presentations
SU-F-708-6 (Sunday, July 30, 2017) 2:05 PM - 3:00 PM Room: 708
Purpose: The depth of penetration (DOP) is important for assessing ultrasound system sensitivity. This study aims to understand how changes in machine settings, selection of phantom, and choice of computerized analysis can affect objective assessments of DOP for Ultrasound scanners.
Methods: We scan a cohort of five phantoms with nominal 0.7dB/cm/MHz attenuation coefficient, and acquire images by systematically varying the transducer frequency, gray maps (GM), or dynamic range (DR) for three scanners (Siemens S2000, GE Logiq S8 and E9) with linear transducers (9L4 and 9L-D). We assess the DOP by finding the depth at which the signal curve of the phantom intercepts the noise-in-air curve adjusted by a factor of 1.4. Two software programs were used for this assessment --- a commercial software called “UltraiQ” and an ImageJ plug-in called “Depth-of-Penetration” developed by our group.
Results: Choosing different GMs caused a maximum DOP change of about 4.3% measured using “UltraiQ” and 6.0% using ImageJ. As the DR increases from 60 to 80 dB, the DOP always decreases. The max DOP decrease is 6.2% for “UltraiQ”.A remarkable consistency in objective analysis indicates that the computerized analysis is sensitive enough to capture DOP differences across individual phantoms of the same nominal attenuation.
Conclusion: Results provide guidance regarding how to perform consistent DOP evaluation objectively, which is critical for improving Ultrasound QA and acceptance tests. The consistent pattern of DOP changes across phantoms can be very useful for phantom manufacturers performing quality control of their products, and can be useful when comparing DOP results from sites with similar phantoms and scanners.
Funding Support, Disclosures, and Conflict of Interest: An early version of UltraIQ software was provided for initial evaluation and feedback.
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