OBJECTIVE: It is necessary to evaluate a possible increase in the environmental gamma exposure rates in the NM as a result of the operation of the new PET facility. METHODS: The TLDs were calibrated using radiotherapy linear accelerator. A one-month two times to evaluate of environmental radiation in the PET/CT was performed using the accurate and sensitive TLD-100H method, which gives an error less than 10%. In this study, the Taguchi method was used to adjust the parameters of the instrument and select the optimal adjustment combination, and then confirm and verify the reproducibility of the experiment. RESULTS: Our analysis indicates that 50°C for the initial temperature, 25 °C/s for the heating time, 220 °C for the max temperature and 10 s for the preheat time are the best choice in terms of readout system. The exposure radiation detected in the PET/CT ranged from 4.66 ± 0.20 mSv/non - 0.199 ± 0.082 mSv/mon, indicating that there was a significant difference in the radiation of the ward. In this study, the Taguchi method was used to adjust the parameters of the Harshaw 3500 system and select the optimal adjustment combination, to confirm the to verify the reproducibility of the experiment, and to discuss the minimum detectable dose (MDD) of environmental radiation. CONCLUSION: This study demonstrated there are no extra radiation hazards among NM.