ACQUISITION
ENERGY SETTING: Tc99m - 140 Kev with a 20% Window.
PLANARS:
- Whole-body Sweep: Starting at the head, scan at 8-10 cm/minute
stopping at the level of the mid-thigh.
OR
- Use a 256x256 Word Mode
- 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.)
- Use a 128 matrix with 3 degree steps for 30-40 seconds/step (the 64
X 64 matrix is adequate, but the 128 X 128 should produce better images).
- 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.
- 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 6 degree steps
and set the acquisition for 60-70 seconds/step.
PROCESSING
PLANAR DISPLAY:
FX and VP 7.23 versions of software and up:
- WORKBENCH
- Select: DISPLAY
- Use: STATIC
- Choose: STATIC 4 DISPLAY
OR
- PIXIE
- Select: RUN MACRO
- Select: STATIC 4
- Check each image varying the intensity to look for any
suspicious areas of uptake.
- Use a linear gray scale taking care to not remove any
background.
- Film images at two intensities: one lighter and the other
dark enough to display the blood vessels intensely.
RAW DATA CINE DISPLAY:
- WORKBENCH
- Use: DISPLAY
- Select: CINE
- Check each SPECT for motion and vary the intensity to look for any
suspicious areas of uptake.
SPECT PROCESSING
SPECT RECONSTRUCTION:
FX & VP COMPUTERS:
SELECT: SPECT TOOLS
- Choose: TRANS RECONSTRUCTION
- Highlight: BEST POST FILTER
- Filter: RAMP
1500/750 COMPUTERS:
- WORKBENCH
- Select: IMAGE PROCESSING
- Choose: TRANSVERSE RECON
- Filter: RAMP
3D POST FILTER:
- Filter: LOW PASS or 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)
OBLIQUE REFORMAT:
FX & VP COMPUTERS:
- SPECT PROCESSING
- Choose: SPECT TOOLS
- Use: OBLIQUE REFORMAT
- Mode: Sag/Cor/Obl
- Slice Thickness: 2
- Center the slices
- Set the limits to include the entire field of view
- Click on REFORMAT
1500/750 COMPUTERS:
- IMAGE PROCESSING
- Use: Sag/Cor/Obl
- Choose: REFORMAT
- Set the first and last slice to include the entire field of
view
- Slice Thickness: 2
- Click on REFORMAT
**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 in this region, it might be a
reconstruction artifact. Process the SPECT of the liver with and without attenuation
correction and compare the images.
SPECT DISPLAY
If the kidneys are extremely hot on the SPECT images, the
Truncation program may be helpful. By eliminating the hottest pixels, the image will be
rescaled allowing visualization of subtle structures. Use care to not eliminate too many
"hot pixels", as this may remove counts from other regions.
**PLEASE NOTE: COMPUTER SOFTWARE CAN VARY FROM SITE TO
SITE.
IF YOU ARE UNABLE TO LOCATE THE TRUNCATION PROGRAM, PLEASE
CONTACT YOUR PICKER APPLICATIONS SUPPORT REPRESENTATIVE.
TRUNCATION:
- Display the transverse images on DISPLAY A.
- Set the Window to 1
- Adjust the BASE control until only the "hottest pixels"
remain visible
- Read the value for the BASE for BAS1A.
- Use IMAGE ALGEBRA under the TOOLS Menu
- Select: COUNT MANIPULATION
- Choose: TRUNCATE COUNTS
- Enter the value from BAS1A window.
- Click on DONE.
- Redisplay the images on the computer screen using the gray
scale.
- Perform the REFORMAT or OBLIQUE REFORMAT to create the slices.
NOTE: the Truncated file will have a TRC. extension. To perform
the Reformat, the program may require the Transverse file to be renamed.
Reviewing the SPECT as a 3D Volume is often helpful.
SELECT: TRANSVERSE FILE
- DISPLAY
- Choose: 3D DISPLAY
- Select: MAX PIXEL RETRACE
SPECT DISPLAY
1500/750 COMPUTERS:
- PIXIE
- RUN MACRO
- Choose: SPECT DSP or SPECT Select
FX & VP COMPUTERS:
- PIXIE
- RUN MACRO
- Choose: Rev SPECT or SPECT Select
OR
- Display
- Choose: General SPECT Display
- *Try: Localizer Option to triangulate images.
**PLEASE NOTE: The factory display macros will display the
first files
processed, so if the study is processed more than once, either delete or
rename the first Sag/Cor/Obl files.
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 and 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 Picker 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.