RT Journal Article
SR Electronic
T1 Primate PET scanner count rate analysis with [F-18]FDG dosed nonhuman primates
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1484
OP 1484
VO 50
IS supplement 2
A1 Charles Laymon
A1 Brian Lopresti
A1 N Mason
A1 M Coleman
A1 Lonnie Frye
A1 James Mountz
A1 Jamie Tomko
A1 Joanne Flynn
A1 Jonathon Carney
YR 2009
UL http://jnm.snmjournals.org/content/50/supplement_2/1484.abstract
AB 1484 Objectives PET image quality is limited by statistical noise. The pseudo noise equivalent count rate (PNECR) of Watson et al. is a related figure of merit. Given a phantom scan spanning a range of singles rates, a full PNECR vs singles-rate curve can be deduced for a subject from data acquired at one singles rate. We calculate PNECR for a series of FDG scans performed on the Focus 220 (Siemens) primate scanner to evaluate dosing strategy. Methods Static 18F FDG PET scans (185 MBq, 1 hour uptake) were performed on macaque monkeys (3-10 kg). Scans focused on the lungs and consisted of 2 or 3 10-min bed positions and included regions outside of the lung. A phantom (11 cm diameter, 17 cm height) was filled with a solution of 11C and dynamically scanned for 6 half lives. Rates of singles and prompt and delayed coincidences were recorded for each monkey scan and at 10 min. time points for the phantom scan. PNECR curves were deduced as a function of singles rate for each bed position of each subject (362 curves). An average curve for all beds/subjects was also generated. Results The average PNECR curve has a broad peak at a singles count rate of 14 – 20 Mcps. On average, scans were performed at a singles rate of 7.3 Mcps resulting in a PNECR value of 83% of maximum PNECR. Each subject's singles rate was below the peak of their individual PNECR curve. Conclusions Additional dose could safely be given to all subjects. In some cases this would result in image quality improvement. However, to maximize the average curve would, considering deadtime, require a dose of 2.5 times the current dose and would result in only a modest increase in PNECR. Research Support Bill and Melinda Gates Foundation