Study On Measure To Control Risk And Setup Of Probabilistic Safety Assessment Model Of PET

This study aimed to apply PSA technology in clinical PET and PET-CT procedures for the safety assessment of occupations at risk of potential exposure. The thesis consists of three parts: First, the analysis of the cyclotron which product the positron radionuclide and the chemical synthesis, the application of failure mode effects and criticality analysis (FMECA) is used in this part; The second part is the safety assessment of common device hardware failure.The fault tree, event tree analysis are used; The third part analyses human errors which will cause occupation potential exposure by the FMECA and fault tree.Results and discussion:1. According to the results of the FMECA about equipment in thesis, we find some high risk hardware failure modes which could cause potential exposure; Fault tree analysis point that a good detection and alarm system can be very effective on prevention of potential exposure. Overall, cyclone 10/5 cyclotron and synthera chemical synthesis is safe, reliable. But if we can improve the safety of high-risk parts, the equipment reliability could be improved significantly. Results of the analysis have some uncertainty, because of assessment data from the engineer's judgment.2. In this paper,the clinical PET procedure was divided up to several parts in accordance with the general tasks and sub-tasks. We identify the risk of large steps in accordance with the views of clinical experts. In the investigation information, we find the risk priority number of the hospital which fit automatic packaging equipment always lower than the hospital with manual;3. Run back over the past experience, human errors (human factors) play an important role in the accident. In this study, we have a analysis of the human error which occur in the work process. We apply fault tree to identify the root events which could cause the potential exposure;4. The device with different model has different effect for the final consequence of potential exposure. Therefore, we must make a specific PSA analysis of the object;5. Such as the cyclotron relatively simple compared with the nuclear power plant, and security systems and support systems are relatively simple, FMECA can be applied in the beginning of the study. We can analyze equipment and provide information for the following work—fault tree. Therefore, it is recommended for the relatively simple equipment or systems, applications combining FMEA and fault tree approach and supplemented by other methods (event tree, function chart, etc.) is appropriate; 6. This is the first time to use PSA in assessment of clinical PET procedure. And this attempt has important theoretical and practical significance in some aspects such as the prevention of radiation accident, reduce the probability of potential exposure.