MR Distortion & Image Fusion Head Phantom

Model 603-GS

CIRS Model 603-GS was designed to assess MR image distortion in Stereotactic Radiosurgery Planning. It’s also a useful tool for verifying image fusion and deformable image registration algorithms used in various treatment planning systems. The tissue equivalent, anthropomorphic design closely matches a clinical imaging scenario. The phantom can be imaged using X-ray, Computed Tomography and Magnetic Resonance. It images well with all MRI sequences tested to date, including T1 weighted, T2 weighted, 3D Time of Flight, MPRAGE and CISS.

The skull is manufactured from a plastic-based trabecular bone substitute, and the interstitial and surrounding soft tissues are made from a proprietary signal generating water-based polymer. The entire phantom is encased in a clear plastic shell to protect gel from desiccation. It’s supplied with specially designed pads that allow fixation with any stereotactic frame or mounting devices for end-to-end testing. The phantom is also suitable for frameless SRS QA.

The entire inter-cranial portion of the skull volume is filled with an orthogonal 3D grid of 2.5mm diameter cross-like shaped rods spaced 10mm (I-S), 10.5mm (AP) and 11mm (L-R). Extra material added in the grid intersections increases grid signal. Five extended axis-rods intersect at the reference origin of the grid. The end of each extended axis is fitted with CT/MR markers allowing for accurate positioning with lasers and co-registration of CT and MR image sets.

The phantom includes right and left air voids, 3 mm in diameter by 17 mm long to simulate each ear canal for evaluation of potential distortions commonly found in clinical settings.

For users interested in image fusion studies, the phantom can be purchased as a kit to include a serial-number specific CT DICOM Data set for reference. CIRS can also offer value-added options and services such as attachment of customer specific registration devices and inclusion of special point markers.

  • Provides a realistic anthropomorphic scenario for CT and MR imaging
  • Presents simulated bony anatomy as rigid landmarks for image fusion
  • Unique inter-cranial 3D grid design used to assess spatial distortion
  • Special pads compatible with all fixation frames
  • CT/MR markers facilitate positioning and image registration
  • 859 control points
  • Works with Distortion Check Software

Data Sheet

MR Distortion & Image Fusion Head Phantom: Data Sheet


MRI Distortion Phantom for SRS: Brochure


Greenwald, C, et al. PRE-CLINICAL VALIDATION OF OPEN SOURCE TOOLS TO CALCULATE AND TRACK MR DISTORTION USING BOTH SMALL AND LARGE FIELD OF VIEW PHANTOMS. University of Saskatchewan, 2018.  Operative Neurosurgery. 2020; 19 (5): 599-607. Oxford University Press. View
“Getting to Grips with MR Image Distortion.” Physics World, 4 July 2019,  2021; View
Peerlings, J, et al. “Characterizing Geometrical Accuracy in Clinically Optimised 7T and 3T Magnetic Resonance Images for High-Precision Radiation Treatment of Brain Tumours.” Elsevier, 2019, View
Yahanda, Alexander T; Goble, Timothy J; Sylvester, Peter T; Lessman, Gretchen; Goddard, Stanley; McCollough, Bridget; Shah, Amar; Andrews, Trevor; Benzinger, Tammie LS; Chicoine, Michael R; 'Impact of 3-Dimensional Versus 2-Dimensional Image Distortion Correction on Stereotactic Neurosurgical Navigation Image Fusion Reliability for Images Acquired With Intraoperative Magnetic Resonance Imaging'. Journal of applied clinical medical physics. 2020; 21 (10): 192-199. View