Evaluation of Positron Emission Tomographic Tracers for Imaging of Papillomavirus-Induced Tumors in Rabbits

Abstract

In this study, simultaneous positron emission tomography (PET)/magnetic resonance (MR) imaging was employed to evaluate the feasibility of the PET tracers 2-deoxy-2-18F-fluoro-d-glucose (18F-FDG), 11C-choline, and 18F-fluorothymidine (18F-FLT) to detect papillomavirus-induced tumors in an established rabbit model system. The combined PET/MR allowed the analysis of tracer uptake of the tumors using the morphologic information acquired by MR. New Zealand White rabbits were infected with cottontail rabbit papillomavirus genomes and were imaged for up to 10 months with a simultaneous PET/MR system during the course of infection. The uptake characteristics of the PET tracers 11C-choline and 18F-FLT of tumors and reference tissues were examined relative to the clinical standard, 18F-FDG. Tracer biodistribution of various organs was measured by gamma-counting after the last PET scan and compared to the in vivo PET/MR 18F-FDG uptake. Increased tracer uptake was found 2 months postinfection in primary tumors with 18F-FDG and 11C-choline, whereas 18F-FLT failed to detect the tumors at all measured time points. Our data show that the PET tracer 18F-FDG is superior for imaging papillomavirus-induced tumors in rabbits compared to 11C-choline and 18F-FLT. However, 11C-choline imaging, which has previously been applied to detect various tumor entities in patients, appears to be an alternative to 18F-FDG.

Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds

“…862 Similar pattern uptake was also observed in rabbits to detect papillomavirus-induced tumors (Figure 172). 863 The only reported monkey study with [ 11 C]choline was performed by Friedland et al in 1983, in which brain imaging and organ biodistribution were studied. 864 [ 11 C]Choline had a rapid brain uptake followed by a rapid decline compared with other organs such as the heart, lung, liver, and kidney.…”

“…[ 11 C]­Choline has shown potential for assessing the degree of inflammation in atherosclerotic plaques to detect cancer (breast, colorectal, papillomavirus, prostate, and brain cancer) and pulmonary arterial hypertension . A biodistribution study of [ 11 C]­choline in normal rats showed high uptake in the kidneys, lungs, liver, and adrenal glands with a gradual decline in the uptake of these organs after 10 min p.i .…”

“…[ 11 C]­Choline whole-body PET (left), CT (middle), and fused image (right) of a NZW rabbit at 10 months post-infection with papillomavirus (scans made 50 min p.i.). Reproduced with permission from ref . Copyright 2014 Decker.…”