High resolution small animal single photon emission computed tomography: uptake of [Tc-99m]bombesin and[I-123]ioflupane by rat brain

Methods. We used two multicrystal HRCs with parallel square hole collimators, whose pure tungsten septa closely fit the crystals, in turn matched with a 4 inch2 position sensitive photomultiplier. HRC1 showed 1.1 mm. and HCR2 2.1 mm. resolution at collimator contact. HRCs performed 180 degrees semi-circular orbits around the head of rats: image reconstruction occurred with ordered subsets expectation maximization algorithms. Resolution of SPECT was measured with a Derenzo Phantom, resulting 1.4 mm for HRC1 and 2.3 mm for HRC2. Three rats were studied with [Tc-99m]HMPAO, 3 rats with [Tc-99m]bombesin (BN) and 48 h later with [123I]ioflupane (DaTSCAN). SPECT studies were reviewed by two experienced operators.

Aim. The aims of this study were: 1) to perform brain single photon emission computed tomography (SPECT) in anesthetized rats with high resolution cameras (HRC) equipped with parallel hole collimation resolution of about 1 mm (HRC1) and 2 mm (HRC2); 2) to assess when and with which radio-tracer HRC1 SPECT shows advantages over HRC2.