Improving patient access and scanner utilization in a busy PET/CT practice

Objectives The Mayo Clinic Positron Emission Tomography (PET) practice conducts over 50 clinical and research studies per day, including whole-body and brain exams using FDG, choline and PIB. As such, establishing a schedule is complicated as these exams have different scan ranges, acquisition durations and uptake times. The goal of this project was to construct a schedule to maximize patient access and scanner utilization, minimize patient wait time and maintain consistent uptake times and regular end-of-day (EOD) operation.

Methods We utilized system engineering methodology to model the patient flow through the PET imaging area. A predictive model was developed to compute the scan duration based on the patient height, scan range prescribed by the physician and time per bed for our BMI-based whole-body protocols. Injection timings, restroom utilization, in-room setup time and a no-show rate of 5% were incorporated in the model. Our three clinical scanners were modeled as ‘first come, first serve’ and it was assumed patients were not scanned prior to their scheduled time. The existing schedule and regularly scheduled time slots of 20 - 40 min duration were modeled to determine the best schedule.

Results A preliminary analysis of 4700 patient studies showed the mean duration of an exam was 25 min and 9% of exams had duration greater than 35 min. The table below summarizes the results of the modeling. It shows that by adopting the 35 minute time slot, scanner utilization increases and patient wait time and EOD will decrease. The simulation also shows that the wait time is relatively constant throughout the day. In addition, a resultant earlier EOD suggests additional time slots can be added.

Conclusions A model was developed to simulate patient flow in the PET imaging area; based on this model a schedule was constructed that maximizes scanner utilization and patient access while decreasing patient wait time.