Colon cancer is a leading cause of death in the US, even though many cases are preventable if tumors are detected early.
One technique to promote screening is Computed Tomography Colonography (CTC). NM404 is a second generation
phospholipid ether analogue which has demonstrated selective uptake and prolonged retention in 43/43 types of
malignant tumors but not inflammatory sites or premalignant lesions. The purpose of this experiment was to evaluate
(SWR x B6 )F1.Min mice as a preclinical model to test MicroPET/CT dual modality virtual colonoscopy. Each animal
was given an IV injection of <sup>124</sup>I-NM404 (100 uCi) 24, 48 and 96 hours prior to scanning on a dedicated microPET/CT
system. Forty million counts were histogrammed in 3D and reconstructed using an OSEM 2D algorithm. Immediately
after PET acquisition, a 93 m volumetric CT was acquired at 80 kVp, 800 uA and 350 ms exposures. Following CT, the
mouse was sacrificed. The entire intestinal tract was excised, washed, insufflated, and scanned ex vivo A total of eight
tissue samples from the small intestine were harvested: 5 were benign adenomas, 2 were malignant adenocarcinomas,
and 1 was a Peyer's patch (lymph tissue) . The sites of these samples were positioned on CT and PET images based on
morphological cues and the distance from the anus. Only 1/8 samples showed tracer uptake. several hot spots in the
microPET image were not chosen for histology. (SWR x B6)F1.Min mice develop benign and malignant tumors, making
this animal model a strong candidate for future dual modality microPET/CT virtual colonography studies.