Korean J Nucl Med.  2005 Feb;39(1):49-56.

Performance Characteristics of MicroPET R4 Scanner for Small Animal Imaging

• Lee BI
• Lee JS
• Kim JS
• Lee DS
• Choi CU
• Lim SM

Abstract

PURPOSE
Dedicated animal PET is useful equipment for the study of new PET tracer. Recently, microPET R4 was installed in the Korea institute of radiology and medical science. In this study, we measured the characteristics of scanner. MATERIALS AND METHODS: Resolution was measured using a line source (F-18: 65 micro Ci, inner diameter: 0.5 mm). The line source was put in the axial direction and was moved from the center of field of view to outside with 1 mm interval. PET images were reconstructed using a filtered back-projection and ordered subset expectation maximization. Line source (16.5 micro Ci, 78 mm) was put on the center of axial direction to measure the sensitivity when the deadtime was under 1%. Images were acquired during 4 minutes respectively from center to 39 mm outward. Delayed count was subtracted from total count and then decay was corrected for the calculation of sensitivity. Noise equivalent count ratio and scatter fraction were calculated using cylindrical phantom. RESULTS: Spatial resolution of reconstructed image using filtered back-projection was 1.86 mm (radial), 1.95 mm (tangential), 1.95 mm (axial) in the center of field of view, and 2.54 mm, 2.8 mm, 1.61 mm in 2 cm away from the center respectively. Sensitivity was 2.36% at the center of transaxial field of view. Scatter fraction was 20%. Maximal noise equivalent count ratio was 66.4 kcps at 242 kBq/mL. Small animal images were acquired for confirmation of performance. CONCLUSION: Performance characteristics of microPET R4 were similar with reported value. So this will be a useful tool for small animal imaging.

Keyword

MicroPET R4; Resolution; Sensitivity; Scatter fraction; Noise equivalent count ratio

MeSH Terms

Animals*
Korea
Noise