The use of PET/CT scans in defining tumour volumes for radiotherapy planning purposes may lead to better tumour volume definition. Reproduction of the radiotherapy treatment position (RTP) during a PET/CT performed for radiotherapy planning may be more accurate if the radiation therapist (RT) is involved during the PET/CT set up. This study aims to determine if there is a time difference between setup of patients for PET/CT scans in the RTP by RTs and routine PET/CT setup by NMTs and also if there is a difference in setup staff radiation dose. 20 patients undergoing PET/CT scans for RTP were studied - 10 head and neck (H&N) patients, 10 lung cancer patients. Scan setup duration was measured using a stop watch that was started when the RT entered the PET/CT room and stopped when they exited. A radiation monitor recorded the highest reading (uSv/hr) to the RT during the setup procedure. This process was also repeated for the NMT setting up patients.
Results are shown in the table below.

Mean Setup Estimated Maximum Dose
RT Group Duration (mm:ss) During Setup (uSv)
Lung 5:20 4.94
H&N 4:45 3.93
NMT Group
Lung 1:34 3.30
H&N 1:43 3.10

This study showed that setup time and radiation dose was greater for RT setup of PET/CT in RTP than the NMT setup of routine PET/CT scans. These results must be considered when performing radiotherapy planning PET/CT.