Phantom Set Up

The Catphan® phantom is positioned in the CT scanner by mounting it on the case.

• Place the phantom case on the gantry end of the table with the box hinges away from the gantry. It is best to place the box directly on the table and not on the table pads.
• Open the box, rotating the lid back 180°. If you are using an annulus, additional weight will need to be placed in the box to counterweigh the phantom. The patient straps can be used for additional stability.
• Remove the phantom from the box and hang the Catphan® from the gantry end of the box. Make sure the box is stable with the weight of the phantom and is adequately counterweighed to prevent tipping.
• Use the level and adjusting thumb screws to level the Catphan®. Once the phantom is level, slide the phantom along the end of the box to align the section center dots on the top of the phantom with the x axis alignment light.
• Use the table height and indexing drives to center the first section’s (CTP401 or CTP404, Slice Geometry) alignment dots on the side and top of the phantom with the scanner alignment lights.
• The z axis scan alignment position can be selected from the localizer scan, by centering the slice at the intersection of the crossed wire image created by the slice width ramps.

Diagnostic Scanning Checklist (Catphan® 600)

Choosing Parameters
Parameters of any clinical protocol can be used as long as the scan and display FOV is adapted to the testing requirements and phantom size. 
Suggested scanning parameters for optimal testing.

• Use scan FOVs close to the centered phantom diameter (210 to 250 mm) unless using an annuli.
• In general use reconstruction FOVs that are close the phantom diameter (~210 mm).
• For measuring slice width 1 mm or thinner use reconstruction FOV ~100-120 mm
• For measuring higher (10lp/cm) spatial resolution use reconstruction FOV ~100-120 mm and reconstruction slice thickness ~3-5 mm. For standard resolution, use ~210-250 mm FOV.
• Off centered zooms are only supported if centered on the MTF bead.

Creating a Protocol
For consistent results, using a pre-programmed protocol is recommended.
Typical technique: 120 kVp, 200-300 mA, 0.5-1.0 sec (In rare cases the max loading of the small focal spot can be as low as 150mA)

1. Orientation: supine - head first.
2. Position the slice groups at the center of the modules as indicated by the measurements on the phantom drawing, using either the first center dots (light alignment or the crossing of the CPT404 wire ramps (localizer view).
3. Recommended settings (see also Suggested scanning parameters for optimal testing.)

CTP404 - Sensitometry

• At least one 5 mm slice

CTP404 - Slice Thickness (Wire ramp)

• 1 or more slices for thick slice thickness (>2mm) to be measured.

CTP591 - Slice Thickness (Bead ramp)

• 1 or more slices for thin slice thickness (<=2mm) to be measured.
• Use of small focal spot may be required for highest resolution

CTP528 - Spatial Resolution

• Two or more adjacent slices for each test covering ~5 mm
• Scanning slice thickness 0.5 - 3 mm
• Recon slice thickness ~3 - 5 mm
• Use of small focal spot may be required for highest resolution

CTP515 - Low Contrast

• Four or more adjacent slices
• Slice thickness 5 or 10 mm (being careful to not exceed the module width)

CTP486 - Uniformity

• One or more adjacent slices
• Slice thickness 5 or 10 mm (being careful to not exceed the module width)
• Store the protocol with a descriptive name (indicating it is not a clinical protocol).

Before Scanning

• Use the Catphan® model and serial # for name and ID (ex: Catphan 600, 600119)
• Enter the name of the test person as a referring physician (optional).
• Select the scan protocol. 
• Align the phantom using the laser guide lines and spirit level.
• Reset the table position to 0.00mm (if possible) when the laser is on the first white alignment pins of the phantom.

Scanning

1. Make a localizer scan (optional).
2. Using clear landmarks in the phantom for spacing and distance information, position a
   slice or slice groups according to the Catphan® model (optional if using the localizer).
3. Make the scan according to previously stored protocol. Additional protocols can be
   performed if desired.
4. Be aware that for constancy measurements the same protocol should be repeated at all
   
   

Submitting data to the Catphan® QA Service

1. Delete slices or scans produced erroneously, or did not follow intended protocols.
2. Login to your account at www.imageowl.com
3. Upload the DICOM data. The upload and processing will complete on its own, however, the window/tab should remain open.
4. Review the results. Reports are organized by upload sessions. To organize by protocol, only upload images from the same scan protocol.