The Catphan® 605 provides a compact, inexpensive phantom with a basic suite of tests to measure maximum performance characteristics of multi-slice CT’s and other state of the art scanners. The Catphan® 605 has enhanced measurement capabilities for precise measurement of thin slices and higher resolutions found in modern multi-slice scanners.


  • CTP682
    sensitometry (linearity)
    scan slice geometry
    slice sensitivity profile
    slice width with both wire and bead ramps
    pixel (matrix) size
    circular symmetry
    phantom position verification
    patient alignment system check
    scan incrementation
    MTF using both wire or bead point source
    contrast targets using volume averaged spheres

  • CTP729
    spatial uniformity
    noise (precision) of CT systems


The Catphan® 605 consists of 2 modules enclosed in a 20cm housing.

CTP682 Slice Geometry and Sensitometry Module:  The CTP682 module contains three sets of opposed slice geometry ramps. Opposed 23 degree ramps are used to measure scan slice geometry, verify phantom position and check the patient alignment system and the scanner table incrementation. The shallow 23 degree angle allows for more precise measurement of slice thickness than the commonly used 45 degree ramps.  The coarse ramp with a z-axis height of 38mm uses 0.28mm beads set in 1mm z-axis increments and the fine ramps use 0.18mm beads set at 0.25mm z-axis increments.  One of the ramp sets uses 0.15mm thin wires to allow for accurate measurement of thin 1 and 2mm slices without streaking artifacts. Gantry angle (up to 10 degrees) can be determined by the ratio of the ramp lengths, thus avoiding erroneous measurements.

The module includes 10 sensitometry targets (Acrylic, Bone-50%, LDPE, Bone-20%, Teflon, polystyrene, Delrin™, Lung Foam #7112, PMP and air, and a small vial for water) to measure CT number linearity. The increased number of targets makes this module suitable for radiotherapy CT sensitometry.

The module also contains eight acrylic spheres to evaluate the scanner’s imaging of subslice spherical volumes. The sphere diameters are 1, 1.5, 2, 3, 4, 6, 8, and 10mm.

CTP729 Uniformity Module: The 20cm diameter image uniformity module is cast from a uniform material with a CT number designed to be within 2% (20H) of water’s density under  standard scanning protocols. The typically recorded CT numbers range from 5H to 18H. This module is used for measurements of spatial uniformity, mean CT number and noise value.

Use of a solid material eliminates leaking or risk of damage from exposure to freezing temperatures. The CTP712 solid-image uniformity module provides consistent results, is much more convenient to use than modules using water-filled tanks, and eliminates variations due to different water sources. This solid material’s high radial and axial uniformity makes it an ideal substitute for water. It has been thoroughly tested over a wide variety of variables in the x, y and z planes and has proven stable in all applications.

For detailed phantom information please refer to the Catphan 605 manual.