• How do customers use Calimetrix phantoms?

- Our spherical, housing-based phantoms provide optimal image quality for independent scans of the phantom as a reference standard. They are ideal for site qualification for clinical trials, periodic quality assurance, and testing of new quantitative MRI methods

- Our phantom packs are available to augment use of housing-based phantoms. They can be placed in the imaging FOV with each patient scan to provide an embedded reference standard. This makes them ideal for on-going quality assurance during a clinical trial and clinical quality assurance.

• If I order 5 phantoms, will the vials in all 5 phantoms have exactly the same values?

There is some minor variability in precise values. However, each phantom undergoes verification in the MRI scanner and the actual measured values are provided with the phantom.

We also offer batch orders, which ensure less variability between phantoms made in the same batch. For more information, ask us about batch orders!

• Can I get the R2*, T2, and T1 phantoms verified at multiple field strengths?

 Product pricing includes MRI verification of the MR parameter being controlled in each vial at 3T. If desired, the same MR parameter can be verified at 1.5T for an additional charge.

• Does the proton density fat fraction (PDFF) depend on field strength?

No, unlike R2*, T2, and T1 phantoms, PDFF does not depend on field strength.

• Do you provide recommended protocols with your phantoms?

Upon request, we can provide protocol recommendations.

Phantom Size and Construction

• What coils do your phantoms fit in?

Our phantoms are designed to fit within most commercially available head coils as well as a variety of other coils.

• What are the dimensions of the spherical phantom?

The spherical housing outer diameter is 7.5”.

• Why are the vials placed asymmetrically inside the phantom housing?

Our vial layouts utilize asymmetric positioning to eliminate any left-right and superior-inferior vial identification ambiguities.

• What is the material for the housing?

The housing components are made of polycarbonate and other MR-safe materials.

• How large are the vials inside your phantom?

Spherical Housing Based Phantoms (Model 300, 450, 600, 725, and 825) contain vials that have a maximum capacity of 22.5ml. Our manufacturing processes fill these vials with approximately 20ml of gel. The vials in Spherical Housing Based Phantoms have an outer diameter of about 27mm and have a length of approximately 60mm.

Phantom Packs contain vials with a maximum capacity of 30ml. Our manufacturing processes fill these vials with approximately 27ml of gel. Phantom Pack vials have an outer main body diameter of approximately 25mm , cap diameter of 31mm, and length of 94mm.

• What is the material for the vials inside your phantom?

In the spherical phantom, the vials are made of hard plastic (HDPE).

Phantom pack orders have vials made of polypropylene.

• Are the contents of your vials liquid?

We build gel-based vials to avoid motion-related artifacts and to avoid susceptibility artifacts caused by bubbles. Our 100% fat fraction vial is the only vial that is not gel-based.

Paying for your Phantom

• How much do your phantoms cost?

Please contact us via our website and we will be happy to provide a detailed quote.

• How can I pay for my phantom(s)?

Payment is due at the time of order. We accept payment by check or by bank transfer (ACH).

Phantom Customization

• Do you build custom phantoms?

Yes! Please feel free to contact us regarding your custom phantom needs.

Application-Specific Questions

• Why does there seem to be a discrepancy between histology results and PDFF measurements?

  Pathologists grade steatosis as the percentage of hepatocytes with at least one vacuole of fat in the cytoplasm. They express this as a percentage, typically reported to the nearest 5%. Pathologists will also bin those percentages into grades: grade 0 (0-5%), grade 1 (6-33%), grade 2 (34-66%), grade 3 (67-100%). The percentage reported by pathologists is entirely different than PDFF, which is defined as the ratio of the number of protons on mobile triglycerides relative to the total number of protons on mobile triglycerides and mobile water. This is a fundamental property of tissue that is similar to, but not the same as, concentration [Reeder SB, et al. On the Definition of Fat-Fraction… Proc. Intl. Soc. Mag. Reson. Med. 17 (2009)]. More information on this topic can be found here: https://pubmed.ncbi.nlm.nih.gov/25247408/ .