Evaluation of the quantitative capability of a high-resolution positron emission tomography scanner for small animal imaging

The quantitative capability of a positron emission tomography scanner for small animal imaging was evaluated in this study. The microPET P4 (Concorde Microsystems, Knoxville, TN) scanner's capability for dynamic imaging and corrections for radioactive decay, dead time, and attenuation were evaluated. Rat brain and heart studies with and without attenuation correction were compared. A calibration approach to convert the data to nanocuries per milliliter was implemented. Calibration factors were determined using calibration phantoms of 2 sizes with and without attenuation correction. Quantitation was validated using the MiniPhantom (Data Spectrum, Chapel Hill, NC) with hot features (5:1 ratio) of different sizes (4, 6.4, 8, 13, and 16 mm). The microPET P4 scanner's ability to acquire dynamic studies and to correct for decay, dead time, and attenuation was demonstrated. The microPET P4 scanner provided accurate quantitation to within 6% for features larger than 10 mm. Sixty percent of object contrast was retained for features as small as 4 mm. The microPET P4 scanner can provide accurate quantitation.