Application of clinical PET imaging to human laryngeal squamous cell carcinoma xenografts

Positron emission tomography (PET) imaging with [F-18]-fluoro-2-deoxy-D-glucose (18F-FDG) is extensively applied in clinical practice. However, in animal experiments, the application of clinical PET is difficult, due to limitations in sensitivity and spatial resolution. This study aimed to determine the potential of 18F-FDG PET with regard to the imaging of human laryngeal squamous cell carcinoma (LSCC) xenografts. Twenty-seven LSCC tumor-bearing nude mice were divided randomly into seven groups which were each handled differently; the anesthetization, fasting, warming and the time point at which scanning was initiated were varied. The size of each xenograft was measured prior to conducting the scan. Using the RAMLA 3D image reconstruction method, images were acquired. The region of interest (ROI) technology was adopted to calculate target and non-target (T/N) ratios. The results were subsequently analyzed by semiquantitative analysis. The analysis showed that there was no significant correlation between tumor size and PET image quality (r=0.381, P>0.05); however, the handling conditions of the mice had a greater influence on the tumor image quality. Fasting increased 18F-FDG uptake (T/N, 1.153±0.008) to a certain degree, although the effect was unstable. By contrast, combining warming and fasting increased 18F-FDG uptake significantly (T/N, 2.0±0.29; P<0.05). The acquisition time had no impact on the tumor image quality. The study demonstrated that the application of clinical PET scanning has potential in the study of human LSCC xenografts in nude mice, and that the quality of the image of the tumor is greatly influenced by the handling conditions of the animals.