The calculation results for the five sites are shown in Table 2. The optimal ROI size was small for prostate cancer and liver cancer, large for lung cancer and pancreatic cancer, and medium for H&N cancer. For all sites, the calculation times for small, medium, and large sizes were 25.1 ± 2.91, 24.3 ± 2.3, and 24.1 ± 1.90 s, respectively. At their optimal ROI size, all calculations in the prostate, lung, and H&N cancer patients were acceptable.