  SPECT systems using pinhole apertures permit radiolabeled molecular
distributions to be imaged in vivo in small animals. Nevertheless studying
cardiovascular diseases by means of small animal models is very challenging.
Specifically, submillimeter spatial resolution, good energy resolution and high
sensitivity are required. We designed what we consider the "optimal"
radionuclide detector system for this task. It should allow studying both
detection of unstable atherosclerotic plaques and monitoring the effect of
therapies. Using mice is particularly challenging in situations that require
several intravenous injections of radiotracers, possibly for week or even
months, in chronically ill animals. Thus, alternative routes of delivering the
radiotracer in tail vein should be investigated. In this study we have
performed preliminary measurements of detection of atherosclerotic plaques in
genetically modified mice with high-resolution prototype detector. We have also
evaluated the feasibility of assessing left ventricular perfusion by
intraperitoneal delivering of MIBI-Tc in healthy mice.
