F A Q ' s

The MollyQ™ for Drug Development

 
How will the technology impact the overall probability of success in preclinical drug development?
 
SPECT directly affect the probability for success in preclinical drug development, and will likely shorten the process thereby saving money. 


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Table comparing the functional imaging technologies...fMRI, PET, CT, SPECT ...etc.


SPECT is an acronym for Single Photon Emission Computed Tomography and is used in nuclear medicine procedures to image the function of body organs.  Gamma camera SPECT has insufficient resolution for diagnostic brain imaging.  The chart at right illustrates the "utility" for brain function imaging versus cost.  MRI (magnetic resonance imaging) and CT (x-ray computed tomography) are used for brain anatomy rather than function.  "Functional" MRI (fMRI) is expensive and limited in the variety of procedures that it is capable of performing.  PET (positron emission tomography) has considerable versatility for functional brain imaging but is very expensive, becoming more so with increasing versatility and resolution.  The MollyQ SFP system provides the best combination of high resolution and sensitivity for functional brain scans at the lowest cost.

How does the technology work?

Functional imaging in nuclear medicine SPECT begins by "tagging" a biologically active molecule with a radioactive atom.  This is called a "radiopharmaceutical" or "biomarker."  A simple example of this process is to use molecules tagged with radioactive technetium atoms that very rapidly pass from brain capillaries into the surrounding brain tissue where they "stick".    When injected into the bloodstream, these tagged molecules are taken up in brain tissue where the blood flow is greatest.  This occurs in the small areas where the neurons are momentarily most active (i.e., thinking).  The additional neuronal metabolic activity demands more oxygen and glucose to which the brain's circulation quickly responds by locally increasing blood flow.  The distribution of the resulting technetium concentration can then be detected externally and a map of brain activity (function) "reconstructed."

The distribution of radiopharmaceuticals can be mapped by gamma cameras or the NeuroPhysics "MollyQ™" scanner.  The latter has major advantages in both resolution and sensitivity.

The operation of the MollyQ™ scanner is the same as the scanning optical microscopes used to obtain high-resolution, three-dimensional images of biological tissue.  A highly focused point of light is mechanically moved about in three dimensions in such a way as to uniformly sample the volume under observation.  Because the energetic gamma rays emitted by the single-photon biomarkers cannot be focused by conventional optics, the MollyQ™ camera uses proprietary gamma lenses™ for this purpose.  This is called scanning focal-point technology (SFP) and is unique to the MollyQ™.  Other SPECT devices use "gamma cameras" that work well with other body organs but do not have the resolution for imaging the functioning of the incredibly complex human brain.

The MollyQ™ is available in three models.  The standard model has an aperture of 175 mm and is designed for high resolution imaging of the primate brain.  Because of its high resolution, it has been extensively used for primates and event tested on rats.  Please see abstract from SNM Convention. Two new versions just for small animals including mice are readying for production. The MollyQ™ 50 is available now and the MollyQ™ 30 will be ready first Q' 2007. The SPF technology described above is "scalable" so that the new, half-size version will have a factor of two, improvement in resolution.

What will be the impact of the technology of drug discovery and drug development?

While we at NeuroPhysics do not have the expertise to fully answer this question, we believe the major impact will be to substantially shorten drug discovery and development times.  Less animal testing will be needed and the same animal can often be used in repeated or serial studies.  A wealth of information is available from the AMI [1]  Dr. John Seibyl has used the standard MollyQ™ for Parkinson's research using a primate model.[2]

What is the applicability of the technology to animals?  to humans?

As has been discussed above, the standard MollyQ™ has been extensively used for human and primate brain research.  Over 100 research papers have been published.  Any animal that can fit into the 175 mm aperture may be scanned.  The small animal versions are ideal for mice and rats.  All versions of the SFP technology have equal or better resolution than PET scanners with the same apertures.
 
What disease areas can the technology be used for (CNS, respiratory, immunology - US; cardio, bone density - Europe) and very importantly -toxicology and pathology?

 
Although the standard MollyQ™ has been used for CNS studies, there is no reason to believe that it and the small animal MollyQ™ cannot be applied to all of the above within the aperture limits of either scanner.

What resources are needed to implement the technology in-house, especially compared to PET ... cyclotron, radiopharm lab, FTEs, etc?
 
SPECT technology using available radiopharmaceuticals requires little more additional facilities than the scanner and a place for it.  If you want to label experimental molecules, chemistry facilities are required with the additional capability for handling low-level radioisotopes.

What types of animals can be imaged?

Any animal that can pass through the 175 mm aperture of the standard scanner or the 50 mm and 30 mm apertures of the small animal versions of the MollyQ™.

What type of resolution (3-D) can be expected?

Imager performance is a compromise between resolution and field of view. The more restricted the FOV, the sharper can be the focus and the better the resolution. But, for any FOV, thanks to its Photon Lens concept, MollyQ™ offers the best combination of resolution, sensitivity, and uniformity that can be had with present technology. In any event, the ultimate resolution will be determined by the number of photons detected and the object contrast.  This is true of PET as well.


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[1] Academy of Molecular Imaging (www.ami-imaging.org).
[2] John Seibyl, MD, PhD (jseibyl@indd.org).