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Multi-pinhole collimation device for small animal micro-SPECT/CT using a clinical scanner

¹ Nuclear Medicine, Cleveland Clinic, Cleveland, Ohio

474

Objectives: The large number of installed clinical hybrid SPECT/CT scanners presents an opportunity for dual-use as micro-SPECT/CT scanners for research, as a low cost alternative to dedicated small animal scanners. A portable multi-pinhole collimation device using existing clinical detectors has been developed to produce micro-SPECT images with sub-millimeter resolution that are co-registered to CT images.

Methods: The device consists of a lead cylinder with 22 tungsten pinholes (0.9 mm diameter) mounted horizontally to a rotary stage, with an animal bed inside the cylinder attached to a linear stage. The entire device is placed on the patient table of a clinical SPECT-CT scanner with SPECT collimators removed. The cylinder rotates step-and-shoot in tandem with the SPECT detectors, and the animal bed is stepped for non-circular sampling (helical or novel "ordered subsets" orbits). Point sources are imaged along with the animal in order to calibrate the system geometry in-place. After SPECT acquisition, the linear stage and patient table are moved to position the animal outside the cylinder and within the CT field of view for imaging.

Results: Feasibility and performance of the device are evaluated with phantom studies. Reconstructed SPECT images show high spatial resolution (micro-Derenzo phantom, 0.75 mm diameter rods), good uniformity, sufficient axial sampling (micro-Defrise phantom), and acceptable quantitative accuracy. The spatial resolution (15 line-pairs per cm) and contrast of the CT images are sufficient for anatomic mapping and for SPECT attenuation correction.

Conclusions: This collimation device uses a clinical hybrid SPECT/CT scanner to produce micro-SPECT/CT images of very good quality. Although the CT images are not true micro-CT images, they are acceptable for many small animal research studies.

Research Support: NIH grant R01-CA119199

This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by DiFilippo, F. PubMed Articles by DiFilippo, F.