• Topic ID: id_23554485
  • Version: 2.0
  • Date: Sep 26, 2020 10:11:55 PM

35cm Phantom Image Series Verification (RT16)

Prerequisites

Overview

1 Acquiring the 35cm Phantom Image Series

Procedure

  1. Mount the Phantom Holder on the head-end of the table.
  2. Mount the 35cm Phantom on the Phantom holder.
  3. Align, level, and center the 35cm Phantom.

    • Align phantom using the internal laser lights.

    • Level phantom using bubble level and the Z Axis knob on the Phantom Holder.

    • Center phantom using the CENTER PHANTOM procedure in the left head SCANNER UTILITIES selection and the X and Y Axis knobs on the Phantom Holder.

  4. Set up the system to scan a single, 64 image or 16 image, 35cm Phantom series.

    MANUAL SCAN PROTOCOL SETUP

    Refer to Table 2 and setup an Axial scan with the parameters shown.

    AUTO SCAN PROTOCOL SETUP

  5. Acquire a single, image series of the 35 cm Phantom.

2 Image Performance Verification

2.1 Series Means (AvXo-AvXc and AvSDo) & Center Smudge

Procedure

  1. Launch the Image Analysis Tool.
    1. From the Global Control Palette, click on the Service Desktop.
    2. From the Service Desktop upper navigational bar, click on the IMAGE QUALITY icon.
    3. In the left navigational area directory, click on IMAGE ANALYSIS.
      note:

      During the Image Analysis process, you will need to switch between the Service Browser screen (to select the image series to analyze) and the Image Analysis screen (to run a particular Auto 1x analysis test). Use ALT/F1 to bring a window to the front. Use ALT/F3 to send a window to the back.

  2. Using the AUTO 1X Tool on the Image Analysis screen, generate a Series Means and Center Smudge report for the 2nd series of the 35cm Phantom acquisition.
    1. From the Service Browser window, select the 35cm Phantom series acquired in Acquiring the 35cm Phantom Image Series.
    2. On the Image Analysis Tool window, click on the AUTO 1X diamond shaped button.
    3. Click on the AUTO 1X rectangular button, select the IMGSER 35CM test from the pull-down menu, slide cursor to the right and select 16X1.25/140KV/550MA/1S or 4X3.75/120KV/200MA/3S from the test pull-down menu, and continue to slide cursor to the right to select AUTO.
    4. Click on the ACCEPT button.
  3. Review the Image Analysis Report data and record the Series Means (AvXo-AvXc, and AvSDc) data and the Center Smudge data for each row in Table 3.
    1. Verify the Overall Test Pass/Fail Indicator Window of the Report display indicates PASS.
    2. Verify the scan parameter values displayed in the report match those in Table 2.
    3. Record the Series Means (AvXo-AvXc, and AvSDc) data and the Center Smudge data for each row in Table 3.

2.2 Band and Streak Artifact

Procedure

  1. Review the 35cm Phantom images acquired in Acquiring the 35cm Phantom Image Series for Bands and Streaks using the Image Works Desktop.
    1. From the Global Control Palette, click on the IMAGE WORKS Desktop.
    2. From the Image Works Browser window, select the 35cm Phantom series acquired in Acquiring the 35cm Phantom Image Series.
    3. From the Image Works Browser window, click on the VIEWER button.
    4. While paging through the 64 images in the series, analyze images for any Band or Streak artifacts. Adjust Window/Level using the center mouse button, as required.
    5. Note any image that appears to have a Band or Streak artifact.
  2. Verify any images noted above (Step 1.e) meet 35cm Phantom Band or Streak Image Performance requirements.
    1. From the Global Control Palette, click on the Service Desktop.
    2. From the Service Browser window, select an image of the 35cm Phantom series acquired in Acquiring the 35cm Phantom Image Series that appeared to have a Band or Streak while reviewing the series in Image Works.
    3. On the Image Analysis Tool window, click on the AUTO 1X rectangular button, select the IMGSER 35CM test from the pull-down menu, slide cursor to the right and select 16X1.25/140KV/550MA/1S or 4X3.75/120KV/200MA/3S from the test pull-down menu, and continue to slide cursor to the right to select BAND or STREAK.
    4. Click on the ACCEPT button.
      note:

      If required, adjust Window/Level using the center mouse button.

    5. Position and size the Band or Streak ROI using the left cursor button.
      note:

      To ensure specifications are properly applied, do not adjust the Reference ROI's for the Band and Streak artifact tests. The Reference ROI's are adjustable after the 1st Accept Modification click.

    6. Click on ACCEPT MODIFICATION twice, to generate a report.
    7. Verify the Overall Test Pass/Fail Indicator Window of the Report display indicates PASS.
    8. Repeat steps b through g, for each image noted in Step 1e.

      Box Size = 173 mm2 to 408 mm2 17 mm (+/- 3.5 mm) x 17 mm (+/- 3.5 mm) 19 (+/- 4 pixels) x 19 (+/- 4 pixels)

      Box Positions: Box 1 = 0 mm x 0 mm Box 2 = 0 mm x -128 mm Box 3 = 128 mm x 0 mm Box 4 = 0 mm x 128 mm Box 5 = -128 mm x 0 mm

3 Failure Recommended Actions

3.1 Series Means (AvXo-AvXc or AvSDo) Failure Recovery

Procedure

  1. Specifications:

    Each Row of the series must pass 35cm Series Means (for the first series scan parameters) specifications:

    • AvXo - AvXc: < +/- 3.

    • AvSDo: < 17.0 for 16 slice; AvSDo: < 10.0 for 8 slice.

  2. Recommended Recovery:

    1. Repeat Detailed Cal for the 35cm Phantom.

    2. Repeat Acquiring the 35cm Phantom Image Series and Image Performance Verification to verify Image Performance.

3.2 Center Smudge Failure Recovery

Procedure

  1. Specifications:

    80% the Rows must pass Center Smudge specifications when re-scanning:

    Center Smudge: Smudge factor < +/- 4.0

  2. Recommended Recovery:
    1. If one image of one row fails (row fails once):

      • Re-scan the 35cm Phantom acquiring two series of images using the same protocol settings as listed in Table 2).

      • Analyze the two 64 re-scanned image series using the Image Analysis IMGSER 35CM -> 16X1.25/140KV/550MA/1s or 4X3.75/120KV/200MA/3s -> AUTO tool.

      • Verify that all the 128 re-scanned images do not fail Series Means (AvXo - AvXc and AvSDo) or Center Smudge.

    2. If more than one image of one Row fails (Row fails more than once) or multiple rows are failing:

      • Repeat Detailed Cal for the 35cm Phantom.

      • Re-scan the 35cm Phantom acquiring three series of 64 images using the same protocol settings as listed in Table 2.

      • Analyze the three re-scanned image series using the Image Analysis IMGSER 35CM -> 16X1.25/140KV/550MA or 4X3.75/120KV/200MA/3s -> AUTO tool.

      • Verify that all the re-scanned images do not fail Series Means (AvXo - AvXc and AvSDo) or Center Smudge.

3.3 Band or Streak Artifact Failure Recovery

Procedure

  1. Specifications:

    • Band Artifact: Band Factor < +/- 2.5 where radius=0~14cm;

      Band Artifact: Band Factor < +/- 3.5 where radius=14~15cm;

      Band Artifact: Band Factor < +/- 12 where radius>15cm

    • Streak Artifact: Streak Factor < +/- 4.0.

  2. Recommended Recovery:
    1. Troubleshoot Band or Streak artifact failures (refer to “Troubleshooting” category).
    2. Repeat Detailed Cal for the 35cm Phantom.
    3. Repeat Acquiring the 35cm Phantom Image Series and Image Performance Verification to verify Image Performance.

4 Finalization

No finalization steps.