A pair of stationary, opposed scintillation detectors in time
coincidence is being used to create planar projection or
tomographic images of small animals injected with positronemitting
radiotracers. The detectors are comprised of arrays
of individual crysA pair of stationary, opposed scintillation detectors in time
coincidence is being used to create planar projection or
tomographic images of small animals injected with positronemitting
radiotracers. The detectors are comprised of arrays
of individual crystals of bismuth germanate coupled to
position-sensitive photomultiplier tubes. The system uses
FERA (LeCroy Research Systems) charge-sensitive ADCs
and a low cost digital YO board as a E R A bus-to-host bridge.
In projection mode, the animal is placed within the 55 mm x
45 mm useful field-of-view of the detectors and images are
formed from coincidence lines that fall close to the normals of
both detectors. In tomographic mode, the animal is placed on
a rotation stage between the detectors and rotated around a
vertical axis to acquire all possible lines-of-response.
Tomographic images are then reconstructed from those lines
falling within a user-specified angle of each detector normal.
In mice, the system is capable of high-speed, whole-body
dynamic projection imaging, and whole body tomographic
imaging of slowly varying tracer distributions. An ECG gating capability is also available for evaluating cardiac
function. This system is currently being used to study tracer
transport in normal and genetically engineered mice.[+][-]
