Program Information
A New Use for CT Dose Monitoring Data: Calculation of Scan Length and Time Duration and Their Relationship to Protocol Performance and Technologist Behavior
A DuPlissis*, T Szczykutowicz , University Wisconsin-Madison, Madison, WI
Presentations
TU-RPM-GePD-IT-5 (Tuesday, August 1, 2017) 3:45 PM - 4:15 PM Room: Imaging ePoster Theater
Purpose: When managing a fleet of CT scanners, assessing scan time as a function of indication for specific scanner models should reflect scanner to scanner variations if protocols are properly tuned to each scanner’s capabilities. In other words, scanners with larger tubes and wider beam collimations should be able to scan faster than lower power and narrower collimated scanners. This work describes an IT based solution to achieve this aim.
Methods: Scan data from 122,270 irradiation events were collected from a fleet of nine scanners using a commercial dose monitoring solution. Within this data, protocols for routine neck, chest, and abdomen were isolated. The DLP and CTDIvol were used to calculate the scan length. The table speed was provided by the dose monitoring software. We plotted the average scan time and length along with their statistical deviations (25/median/average/75th percentiles) for each scanner.
Results: As expected, the scanner with the highest tube power rating and widest beam collimation demonstrated faster scan times than the lower power/smaller collimation scanners. The 25th-75th percentile ranges for scan length overlapped for all scanner models as expected, i.e. exams had the same body coverage on all scanners. For a routine abdomen pelvis protocol, the average scan speed was 32, 42, and 52 mm/s for the slowest (16 slice scanner), all scanners, and the fastest (64 slice scanner) respectively. We used box and whisker plots of scan time and speed to identify outlier cases of small scan ranges (~2 cm) which were found to be linked to technologists missing tissue and going back to re-scan it.
Conclusion: This methodology uses an accepted form of data collection but analyzes it in a different manner to provide scan time/length information. We identified cases using this data that aided in technologist’s quality monitoring and confirmed our scanner specific protocol tuning.
Funding Support, Disclosures, and Conflict of Interest: TPS received an equipment grant from and is a consultant to GE Healthcare, supplies CT protocols to GE Healthcare under a licensing agreement, and is the founder of protocolshare.org.
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