Speaker
Neal Clinthorne
(University of Michigan)
Description
To assist our ongoing investigations of the limits of the tradeoff between spatial resolution and noise in PET imaging, several PET instruments based on silicon-pad detectors have been developed. The latest is a segment of a dual-ring device to demonstrate that excellent reconstructed image resolution can be achieved with a scanner that uses high-resolution detectors placed close to the object of interest or surrounding a small field-of-view in combination with detectors having modest resolution at larger radius. The outer ring of our demonstrator comprises conventional BGO block detectors scavenged from a clinical PET scanner and located at a 500mm radius around a 44mm diameter field-of-view. The inner detector—in contrast to the high-Z scintillator typically used in PET—is based on silicon-pad detectors located at 70mm nominal radius. Each silicon detector has 512 1.4mm x 1.4mm x 1mm detector elements in a 16 x 32 array and is read out using VATA GP7 ASICs (Gamma Medica-Ideas, Northridge, CA). Even though virtually all interactions of 511 keV annihilation photons in silicon are Compton-scatter, both high spatial resolution and reasonable sensitivity appears possible. The system has demonstrated resolution of ~0.7mm FWHM with Na-22 for coincidences having the highest intrinsic resolution (silicon-silicon) and 6–7mm FWHM for the lowest resolution BGO-BGO coincidences. Spatial resolution for images reconstructed from the mixed silicon-BGO coincidences is ~1.5mm FWHM demonstrating the “magnifying-glass” concept. In the next months, the system will be upgraded to silicon detectors having 1mm x 1mm pads.
Primary author
Neal Clinthorne
(University of Michigan)
Co-authors
Andrej Studen
(Jozef Stefan Institute)
Borut Grosicar
(Jozef Stefan Institute)
Carlos Lacasta
(IFIC/CSIC University of Valencia)
D Shane Smith
(Ohio State University)
Dejan Zontar
(Jozef Stefan Institute)
Enrico Chesi
(CERN)
Eric Cochran
(Ohio State University)
Harris Kagan
(Ohio State University)
Karol Brzezinski
(IFIC/CSIC University of Valencia)
Klaus Honscheid
(Ohio State University)
Marko Mikuz
(Jozef Stefan Institute)
Peter Weilhammer
(CERN)
Sam Huh
(University of Michigan)
Vera Stankova
(IFIC/CSIC University of Valencia)
Vladimir Linhart
(IFIC/CSIC University of Valencia)
