Fast spiral SPECT with stationary γ-cameras and focusing pinholes.
Small-animal SPECT systems with stationary detectors and focusing multiple pinholes can achieve excellent resolution-sensitivity trade-offs. These systems are able to perform fast total-body scans by shifting the animal bed through the collimator using an automated xyz stage. However, so far, a large number of highly overlapping central fields of view have been used, at the cost of overhead time needed for animal repositioning and long image reconstruction times due to high numbers of projection views.


METHODS
To improve temporal resolution and reduce image reconstruction time for such scans, we have developed and tested spiral trajectories (STs) of the animal bed requiring fewer steps. In addition, we tested multiplane trajectories (MPTs) of the animal bed, which is the standard acquisition method of the U-SPECT-II system that is used in this study. Neither MPTs nor STs require rotation of the animal. Computer simulations and physical phantom experiments were performed for a wide range of numbers of bed positions. Furthermore, we tested STs in vivo for fast dynamic mouse scans.


RESULTS
We found that STs require less than half the number of bed positions of MPTs to achieve sufficient sampling. The reduced number of bed positions made it possible to perform a dynamic total-body bone scan and a dynamic hepatobiliary scan with time resolutions of 60 s and 15 s, respectively.


CONCLUSIONS
STs open up new possibilities for high throughput and fast dynamic radio-molecular imaging.
Delft University of Technology, Delft, The Netherlands. p.e.b.vaissier@tudelft.nl
Pieter E B
PE
Vaissier
Marlies C
MC
Goorden
Brendan
B
Vastenhouw
Frans
F
van der Have
Ruud M
RM
Ramakers
Freek J
FJ
Beekman
D000818:Animals; D001659:Biliary Tract / Q000000981:diagnostic imaging; D001842:Bone and Bones / Q000000981:diagnostic imaging; D015902:Gamma Cameras; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D051379:Mice; D019047:Phantoms, Imaging; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation*