<qa>  What is the larger dose of solution?If you are found to be eligible to take part in this study, you will be assigned to an imaging study date. The first group of 6 participants will receive a smaller dose of solution less than one half of the regular PET scan tracer radioactivity. The later 2 groups may receive the same dose of solution or a larger dose, but the larger dose will still be no more than what you would receive in a regular clinic PET scan procedure. 