The main PET blood analysis function. Called by main(). Calls clean_list(), FileFindFirst(), SynchronizeClocks(), GetRunNumber(), check_preweigh_data(), check_patient_data(), check_sample_times(), check_weigh_data(), pet_analysis_scale(), pet_analysis_counter(), and pet_analysis_done(). This function ensures that the PC clock is synchronized with CELIA, gets the most recent run number from BRUTUS, and then prompts the user to confirm the run number. Once a run number has been entered, the function checks to see if any data is already related to this study, and loads it if it exists. The final purpose of this function is to set up the menu, and dispatch to either pet_analysis_scale(), pet_analysis_counter(), or pet_analysis_done() depending on the user's choice.