Publication | Closed Access
Ultra-high resolution SPECT system using four pinhole collimators for small animal studies.
206
Citations
0
References
1995
Year
We describe a newly developed ultra‑high resolution SPECT system using four pinhole collimators for small animal studies. The system employs a clinical four‑head SPECT scanner equipped with four custom pinhole collimators of varying aperture sizes (1.0–4.0 mm) and rotating radii (40–50 mm), a fixed 180 mm source‑to‑detector distance, and a filtered back‑projection reconstruction after fan‑beam to parallel‑beam conversion. The system achieved a 1.65 mm FWHM spatial resolution and 4.3 kcps/microCi/ml sensitivity, enabling clear visualization of small rat brain structures and cardiac compartments with 99mTc‑HMPAO and 99mTc‑MIBI, and successful dynamic 123I‑iomazenil brain imaging, demonstrating its utility for in‑vivo regional tracer distribution studies and potential impact on radiopharmaceutical development and disease model research.
We describe a newly developed ultra-high resolution SPECT system using four pinhole collimators for small animal studies.The system utilizes a clinical four-head SPECT scanner with specially designed pinhole collimators. Four types of pinholes with different configurations were designed with different effective aperture sizes (1.0, 2.0 and 4.0 mm) and rotating radii (40 mm and 50 mm). The distance from the axis of rotation to the scintillator was fixed to 180 mm. A filtered backprojection algorithm was used to reconstruct SPECT images after fanbeam-to-parallel-beam data conversion.The system provided a reconstructed spatial resolution of 1.65 mm (FWHM) and sensitivity of 4.3 kcps/microCi/ml with the best type of pinholes, respectively. The 99mTc-HMPAO SPECT image in rat studies clearly visualized small brain structures, and the left ventricular myocardium and cardiac cavity were clearly separated with 99mTc-MIBI. Dynamic SPECT imaging of rat brain with [123I]iomazenil was also feasible.This ultra-high resolution SPECT system can be used to measure the regional distribution of radiolabeled tracers in small animals in vivo and may play a significant role in the development of new radiopharmaceuticals and in studies of various disease models using living animals.