Virtual-Pinhole PET

• DOI: 10.2967/jnumed.107.043034
• Publication Date: 2008-02-21T01:54:10Z
• Authors: Yuan-Chuan Tai; Heyu Wu; Debashish Pal; Joseph A. O'Sullivan
• Keywords: Pinhole (optics); Collimated light; Point source

We proposed and tested a novel geometry for PET system design analogous to pinhole SPECT called the virtual-pinhole (VP-PET) determine whether it could provide high-resolution images. <b>Methods:</b> analyzed effects of photon acolinearity detector sizes on resolution extended empiric formula reconstructed image conventional earlier predict resolutions VP-PET. To measure VP-PET, we recorded coincidence events as ²²Na point source was stepped across line response between 2 detectors made from identical arrays 12 × lutetium oxyorthosilicate crystals (each measuring 1.51 10 mm³) separated by 565 mm. resolution, built 4 VP-PET systems using types (width, 1.51–6.4 mm) imaged sources ⁶⁴Cu (half-life = 12.7 h allow long acquisition time). Tangential radial were measured averaged each system. then polystyrene plastic phantom representing 2.5-cm-thick cross-section isolated breast volume. The filled with an aqueous solution (713 kBq/mL) in which following imbedded: spheric tumors ranging 1.8 12.6 mm inner diameter (ID), 6 micropipettes (0.7- or 1.1-mm ID at 5×, 20×, 50× background), 10.0-mm outer-diameter cold lesion. <b>Results:</b> shape full width half maximum spread functions agree well predicted values. Measured (2.40–3.24 ±6% value 3 systems. In one case, difference 12.6%, possibly due underestimation block effect low-resolution detector. experiments, all detected. Small detected if activity concentration is least 20× background. <b>Conclusion:</b> have developed characterized PET. A provides images objects near system9s detectors. This may lead development special-purpose resolution-enhancing insert devices scanners.