Abstract
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Objectives: Semiquantitative determination of FDG activity, based upon lesion to background FDG activity, has been shown to be clinically useful in the determination of tumor response to treatment. Evaluation utilizing SUV values alone may be problematic due to inherrent intrinsic limitations. In the past, multiple reference tissues have been used for this purpose. We evaluated the inter-patient reproducibility and variance of multiple reference tissues in order to choose the most reliable for use in semiquantitative determination of FDG activity.
Methods: 12 patients with at least 3 consecutive PET/CT studies were included. Using a standard region of interest, SUV measurements were made on each scan of the cerebellum, lung, liver and mediastinal blood pool. Height, weight, FDG dose and uptake time were also collected from each scan. A statistical analysis of the variance and reproducibility of each tissue was performed.
Results: Mediastinal blood pool showed the least inter-patient coefficient of variance of 0.17, the liver was 0.21, the lung was 0.22 and the cerebellum was 0.25. Differences in height, weight, injection dose and uptake time did not affect the reference tissues SUV values significantly. A glucose level affect was noted only in cerebellar activity.
Conclusions: Based on our analysis, the mediastinal blood pool showed the best clinical performance as a reference tissue for semiquantitative analysis.
- Society of Nuclear Medicine, Inc.