ACQUISITION

ENERGY SETTING:     Tc99m - 140 Kev with a 20% Window.

PLANARS:

• Whole-body Sweep: Scan speed of 8 - 10 cm/minute starting at the head to the level of the mid-thigh.

OR

• Use: 256x256x16 matrix
• Spot Views: Anterior and Posterior Views for 10 minutes/image of the pelvis, abdomen and chest.

SPECTs:     (Always acquire the Pelvic SPECT before the Abdominal SPECT.)
The 64 X 64 matrix is adequate, but the 128 X 128 should produce better images.

• Single-head SPECT:
•     Use a 128x128x16 matrix*
•     64 azimuths for 30-40 seconds/azimuths.
• Dual-head SPECT: Acquisition Parameters: Single Study;
•     Relative Angle: 180; Total Rotation: 360.
•     Matrix size 128x128x16
•     128 azimuths for 30-40 seconds/azimuths.
• Pelvic SPECT: Position the camera to include the groin to above the bifurcation.
• Abdominal SPECT: Position the camera to include the entire liver allowing for some overlap from the Pelvic SPECT.

*If the SPECT acquisition is count deficient, use the image manipulation menu to convert the matrix from 128 to 64.

• Chest SPECT: (Acquire the chest SPECT ONLY if there is a clinical indication; image at approximately 18-24 hours post injection.) Position the camera to include the entire chest and the axilla. Use a 64 matrix with 64 azimuths and set the acquisition for 60-70 seconds/azimuths.

PROCESSING

PLANAR DISPLAY:

• Check each image by varying the intensity to look for any suspicious areas of uptake.
• Use a linear gray scale taking care to not remove any background.
• For Whole-body Sweep: Use Total Body-4 Zone.
• Film the images at two intensities: one lighter and the other dark enough to display the blood vessels intensely.

RAW DATA CINE DISPLAY:

• Check each SPECT for motion and vary the intensity to look for any suspicious areas of uptake.

SPECT PROCESSING

SELECT: CLINICAL PROCEDURES

• Select: SPECT PROCEDURES
• Choose: SPECT RECONSTRUCTION
• Use: Raw image file
• Y-axis filtering: ANALYTIC
• Filter: BUTTERWORTH
• Order: 6-10 (Use a lower order if the study is count deficient.)
• Cutoff: .25-.45 (Use a cutoff which displays sharp edges of the vessels.)
• Set reconstruction limits to include the entire field of view.
• Click on PROCEED to check proper filtering of Transverse image. (The image should look less smooth than cardiac images, but vessels should have sharp edges.)
• Click on QUIT and SAVE the Transverse file.

**ATTENUATION CORRECTION: (Use only for the SPECT of the liver, if necessary.)

Occasionally the liver will display a dark rim particularly on the lateral edge of the right lobe. If there is a question of a lesion at the edge of the liver, Attention Correction may help differentiate between a reconstruction artifact and disease. Process the SPECT of the liver with and without attenuation correction and compare the images.

SELECT: CLINICAL PROCEDURES

• Select: SPECT Procedures
• Choose: ATTENUATION CORRECTION
• Use: TRANSVERSE FILE
• Choose isotope: Tc99m; calibration factor should appear
• Click on PROCEED
• Define the ellipse to fit the contours of the selected view
• Click on PROCEED to accept the ellipse
• Click on PROCEED to apply the ellipse to all of the slices
• Click on QUIT and SAVE: Transverse-AC

SELECT: DISPLAY / REVIEW

• Select: SPECT Display
• Choose: SPECT Display & 3D
• Use: TRANSVERSE FILE
• Click on SELECT DEFAULTS
• Use 2 pixels for each slice.
• Check each file: TRANSVERSE, SAGITTAL, and CORONAL
• **To Save Defaults: Click on SAVE DEFAULTS:
• Create name: CEA SCAN (Use this default for future CEA scan processing.)
• Click on PROCEED to continue processing.
• To Create slices: Click on 2D
• Click on SAVE in the red region and use the red limit line on the reference image to define the first image limit.
• Click on PROCEED. Use red limit line to define second image limit.
• Click on SAVE.
• Repeat the same procedure for the green and blue regions.

Use SPECT DISPLAY & 3D to evaluate the CEA scan:

• By moving one of the colored limit lines on the reference images on the right side of the screen, the images on the left side of the screen will change.
• Start with one colored limit line and slowly move through the image.
• When a suspicious structure appears, use the mouse to move the cursor to the images on the far left of the screen.
• By holding down the middle button on the mouse, cross-hairs will appear.
• When the middle button is released, the corresponding other two planes will appear on the left side of the screen.
• Repeat this method using each of the colored limit lines to triangulate suspicious structures.

**The cross-hairs will only appear on the first column of images on the far left. Remember to vary the intensity to bring out any subtle structures.

Reviewing the SPECT as a 3D Volume is often helpful.
SELECT: SPECT DISPLAY & 3D,

• Click on 3D.
• Depth: should equal the acquisition matrix.
• Views: 32
• Method: TRANS
• Mode: INTP
• Weight: Start at LOG3
• Smooth: OFF
• Thr: 1.00
• Click on CREATE.
• Click on SAVE when the 3D Volume is created.
• Use the ZOOM to change the size of the 3D Volume.
• Click on CINE.
• Click on PAUSE.
• Use the STEP to slowly view the image.

SPECT DISPLAY

The SPECT DISPLAY & 3D can also be used for filming. Since it displays all three planes simultaneously, this is a concise method for documenting the suspicious areas of uptake. The 3D Volume can also be included on the same image. By using the CINE and the STEP, the 3D Volume can be rotated to display the best angle for filming.

To film the entire study:
SELECT: DISPLAY / REVIEW

• Use: DYNAMIC DISPLAY
• Choose: 12 images display
• Film: Transverse, Sagittal, and the Coronal images

HELPFUL TIPS:

• Do not use any Zoom during the acquisition.
• Display a maximum of 16 images for filming.
• Read the study on the computer screen, document the abnormalities on film.
• Some images may require filming with two or more intensities.
• The use of 3D Volume Display may be helpful.

DISCLAIMER:

This procedure was not developed by, or is not meant as an endorsement by Adac of CEA-Scan.  These suggested parameters are based on the experience of various users with this type of equipment and are not a substitute for the physician's or technologist's professional experience or knowledge. Users are ultimately responsible for determining if this procedure is usable with their equipment and standard practices. It is assumed that Quality Control of the imaging equipment is performed according to the manufacturer's recommendations. Please refer to the full product prescribing information and consult your equipment manufacturer's updated user's manual prior to the first use of CEA-Scan.