A 71-year-old with an uncertain parkinsonian syndrome is referred for dopamine transporter SPECT/CT to help separate degenerative from non-degenerative causes. The department must finish everything in one visit because the patient travels two hours each way, the product labeling calls for thyroid protection before injection, and imaging has to fall within a defined post-injection window. Which preparation and timing sequence meets all three requirements for this dopamine transporter SPECT/CT?

The required sequence is to administer an approved thyroid-blocking agent at least 1 hour before tracer injection, then begin SPECT/CT 3 to 6 hours after injection. This protects the thyroid as specified while keeping preparation, injection, and imaging within one visit and the acquisition in the defined post-injection window. Giving the blocking agent 45 minutes before injection keeps imaging in the stated window and the process to one visit, but does not meet the required minimum pretreatment interval. Waiting 6.5 hours after injection preserves the required pretreatment interval and single-visit plan, but places imaging outside the defined window. Having a brief preparation visit the day before meets the medication interval and can be followed by imaging within the labeled window, but does not allow the full process to be completed in one visit. An exam caveat is that the blocking agent and its timing must follow the specific product labeling; do not assume timing for one agent applies to another. In practice, confirm that the agent and its administration time are documented, and check the planned acquisition time against the actual injection time before proceeding.