The Boxplot by Scanner report compares data between scanners within a single facility or across multiple facilities.

You can access the report by selecting Standardized Dose Index Reports from the Interactive Reports menu, and then clicking the Boxplot by Scanner tab. You must first select at least one Facility ID and an RPID or Study Description to generate the report.

The remaining report filters and parameters are set to default values and may be changed at any time:

  • DIR Measure (unit of measure): Dose Index type CTDIvol, DLP or SSDE; either maximum value across scans or total for the exam

Note: Maximum and total values are equal for single-scan exams

  • Exam Year and Date range

  • Age Group

  • Query by: determines whether the RPID / Study Description filter uses standardized RPID exam names or Study Descriptions, as submitted by the facility

  • Body Part: restricts the RPID / Study Description filter to exams for the specified body part

  • Scanner(s)

  • Benchmarks: Data for the entire registry may be highlighted on the graph. The 75th percentile is selected by default. Only data for the oldest age group are used for benchmarking. Benchmarks are not highlighted in the following cases

    • User selects None

    • No registry benchmarks are available for the selected RPID

    • User selects Study Description for the Query by parameter

Note: DIR benchmarks are available only when Query by is set to RPID because Study Descriptions are not standardized and cannot be aggregated across DIR facilities.

  • Scanner Aggregation Level: determines whether to aggregate scanner data in the chart by device name, model, or manufacturer

The following example shows the distribution of measures by scanner for brain CTs, without contrast, in the first three months of 2018, using the following criteria:
  • DIR Measure: CTDIvol Max across scans

  • Age Group: All

  • Date Range: January 1 – March 31, 2018

  • Scanners: All

  • Query by: RPID


DIR Interactive Reports - Sample Boxplot by Scanner 1

The report shows boxplots for each of the scanners meeting the filter criteria. The Age Group table shows the benchmark values for the entire DIR, by age group, as well as the exam counts for the selected criteria. The scanners table shows the number of exams and minimum, maximum and mean values for the selected measure. Scanner statistics are color coded in red indicating the largest values within each column.

Changing the Scanner Aggregation parameter from Device to Model provides a more useful comparison, as CTDIvol for the same exam may vary for different Scanner models to obtain the same quality diagnostic image.

DIR Interactive Reports - Sample Boxplot by Scanner 2

Because dosage varies by size, we can also further restrict the data to age group 0-2 to  identify any outliers.

DIR Interactive Reports - Sample Boxplot by Scanner 3

In the above example, one scanner model appears to be an outlier for the age group and exam compared to the DIR 75th percentile, although this based on only three data points. Additional information is available for each plotted data point by hovering over it with the cursor.

DIR Interactive Reports - Sample Boxplot by Scanner 4

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