This is a feasibility study on improving the spatial resolution of clinical PET, by slightly renovating the
PET scanner design such that high spatial resolution working modes (HSRWM) are achievable.
Introduction: The poor spatial resolution of prevalent PET imaging has restrained its sensitivity in
imaging small lesions, e.g. early-stage cancers or small metastasis. This drawback is caused by 2
essential requirements in clinic: A relatively large diameter (e.g. 80cm) for PET scanner to accumulate
patients, and sizeable scintillator detectors to maintain a reasonable collecting efficiency. In recent
decade more efforts focused on improvement of detector resolution, e.g. digital PET, since the
request on ring diameter is fundamental.
Methods: The novel concept of equivalent position of imaging was proposed for the first time. A
typical static PET scan can be virtually considered as superposition of m equivalent sub-scans at m
different equivalent imaging positions, when the scanner ring is systematically adjusted its angular
orientation within one detector size. In this case each detector is virtually divided into m equal subdetectors,
without physical minimizing the detector size. The contributions of those sub-scans are
analytical by an m x m matrix. The time for performing a high-resolution scan could be comparable to
a typical PET scan, as long as the Poisson noises are insignificant to low-uptake voxels.
Discussion: Three dimensional modeling for imaging at different m were also conducted. As a result,
for a typical scanner design e.g. 80cm in diameter with 18F as tracers, the spatial resolution of double
sub-scans (m =2) is 2.56mm, and 2.19mm for triple sub-scans (m=3). Scanning at high m (m>2) will
slightly drop contrast resolution, hence m=2 is preferably recommended.
Conclusion: As a compatible approach to digital PET and other technological renovation, the novel
HSRWM design is feasible, enabling PET to image small lesions in clinic.
Author (s) Details
Assistant Professor Department of Radiation Oncology, Penn State Health Milton S. Hershey Medical Center Hershey, PA 17033-0850, USA.
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