
The Head Phantom is based upon a standard RSD head with a
calvarial cut to insert or remove the brain shell easily. The
nasal cavity and maxillary sinuses are filled with foam with a
mass density of 0.23 g/cc.

The brain shell has five compartments which can be filled
separately: left and right nucleus caudate, left and right
putamen, and the remainder of the brain. This allows different
nucleus caudate to putamen ratios as well as different
striatal to background ratios to be obtained; this also
permits differences between left and right striatal activity
to be examined.
The volume of the brain shell is about 1,260 ml. The volumes
of the nucleus caudate and putamen are 5.4 ml and 6.0 ml
respectively.

A set of fillable capsules is provided to serve as external
markers. Capsules can be filled with a radioactive solution
and attached to the external surface of the phantom. The
phantom can then be imaged, using SPECT or PET modalities to
compare image-registration techniques.

Quantification of striatal uptake is not straightforward
because it depends on a number of factors:
- Type of radionuclide used (Tc-99m, I-123 or F-18)
- Imaging factors such as: collimator type, amount of scatter and attenuation
- Image processing parameters such as: scatter and attenuation-correction techniques, type of reconstruction filter, slice thickness, region-of-interest size and its location.
In normal subjects, the putamen and head of the nucleus
caudate are small structures with typical dimensions of 7-15
mm in the axial plane (that is comparable to the system
resolution). Since partial volume effects are more important
for objects with dimensions less than twice the system
resolution, the selection of imaging and reconstruction
parameters is critically important in calculating the striatal-to-occipital
ratio used to measure the relative striatal uptake in the
brain.

Nuclear Medicine orders are handled exclusively by Capintec.
For International:
Capintec
6 Arrow Road
Ramsey, NJ 07446
Ph: 201-825-9500
Fx: 201-825-4829
Email: reve@capintec.com
For Domestic: the address is;
Capintec
620 Alpha Drive
Pittsburgh, PA 15238
Ph: 412-963-1988
Fx: 412-936-0610
email:
ERytel@capintec.com
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