γ Radiation Detection Of The Preparation Workplace Of PET-CT And Analysis Of Pharmacy Personnel Exposed Dose

Malignancy cancer is one of the most concerned diseases in the world. In the disease mortality spectrum, the mortality rate of malignancy cancer has leaped to the second place. In the aspects of tumor diagnosis, staging, restaging, efficacy monitoring and prognosis judgment, etc., PET-CT has an important clinical value. PET-CT is molecular imaging equipment, which reflects human tissue cells blood flow, function, metabolism by radionuclide to form molecular images. PET-CT is an organic combination of both PET and CT devices together to achieve PET images and CT images complementing each other. It is the only technology of using dynamic morphology way to make functions, metabolism and receptor image. Meanwhile, it can make a non-invasive, dynamic and quantitative observation of physiological and biochemical changes of the drug or metabolites entering the body from a molecular level. The molecular imaging property of PET-CT lines in that it needs to inject a radioactive nuclide into the body as a tracer which is not only imaging on the PET but also releasesγ-ray which inevitably creates a ray radiation on the examinees and the related personnel.So far, most of the literatures at home and abroad are clinical research, and a small number of articles on exposed doses are only about the examinees and the working personnel being in contact with the examinees. But there is no relevant report on the exposed dose of pharmaceutical personnel not being in contact with the patients. The working environment and exposed doses of the pharmaceutical personnel are studied in this paper.Taking ¹⁸F-FDG for example (hereinafter referred to as FDG), ¹⁸O water enters the cyclotron and turns ¹⁸O into ¹⁸F through the principle of the cyclotron accompanied by the production of radioactive nuclide. ¹⁸F imports into the synthesizer via a specific protection tunnel and produces FDG. The cyclotron and the synthesizer are both computer remote control device. When FDG is produced, take out the lead-tungsten alloy protected lead barrel with FDG manually, put it in the protective shield in the subpackage room, extract doses the examinees need one by one, place them into lead-kit and hand them to the nurses through the window. The cyclotron, corridors and synthesizers are used as the monitoring sites.As the installation of door chains device in the cyclotron room, we can only select cyclotron points peripherally. According to the principles of point selection from GBZ161-2004 "Medical treatment ofγ-beam long-range protection and safety standards", eight points were selected as monitoring points around the cyclotron room's outer wall.Air kerma rates were measured at the time of the accelerator beginning to work, working for 15 minutes and working for 30 minutes. Each point was measured three times continuously, averaged, and measured 3 months continuously. The results show that the longer the accelerators work, the greater nuclides are produced. But the air kerma rate around the external of accelerator has no significant change and the radiation level of each testing point around external wall differs little; the air kerma rate close to the drug transmission channel is slightly greater. All testing points are slightly higher than the background, in line with national regulations.Point selection of corridors starts from the lead door of the cyclotron room. Select two points 0.3 meters away from the lead door, 1 meter from the left and right respectively, at 1.2 meters height. Then walk 1 meter outside and select two points at the same height. Select eight points in analogy. Monitoring time and method is the same as that of cyclotron. The results show that though accelerators work longer, the corridor's air kerma rate has no significant change. But the air kerma rate of corridor is slightly higher than when the accelerator does not work, and the farther it is away from the accelerator, the lower the radiation level of the corridor is. All testing points are slightly higher than the background.According to the principles of point selection from GBZ161-2004 "Medical treatment ofγ-beam long-range protection and safety standards", eight points were selected as monitoring points around the periphery of the synthesizer. Air kerma rates were measured at the time of the synthesizer beginning to work, working for 15 minutes and finishing working. Each point was measured three times continuously, averaged, and measured 3 months continuously. The results show that all testing points are in line with national regulations. The air kerma rate of synthesizer when it works is slightly higher than that of the pre-synthetic and post-synthetic steps.With the more and more widespread application of radiation and radioactive nuclides in the medical field, the team of medical workers in occupational exposure has been greatly enlarged. While benefiting mankind, there is inevitably a risk of radiation hazards. Thus, the issue of occupational exposure limits is highlighted. As during the preparation of 18F-FDG, there is good Protection equipment with the cyclotron and the synthesizer themselves and the staff are of remote control, so I focused the staff's individual dose measurements on the whole process from taking lead pot manually at the end of synthesis to manual sub-drugs.The three thermoluminescence personal dosimeters were worn on the pharmaceutical staff's left chest, measured the absorbed dose in the whole working process, and the other was placed in the office as a background. They were continuously worn for 3 months. The results are as follows: the annual effective dose equivalent of the accelerator and synthesizer operators is 1.84mSv; that of staff responsible for pumping drugs (who are also in charge of taking lead pots) is 1.92mSv. The dose value of pumping drug officers is higher than that of the two members only participating in pharmaceutical, but lower than that of the annual dose limits for occupational workers.Measure the dose equivalent rate with PM1621-type personal dosimeter at the distance of 5 centimeters around the body surface of the eye, the left chest, the right arm, the right hand fingers and legs respectively when the staff hold the pots and measure the needed time for the whole process with a stopwatch. The measurement continued for 3 months. The results showed that the annual cumulative effective dose equivalent in the left chest of pumping drugs personnel was 0.056 mSv; that in the eye is 0.053 mSv; that in the limbs is 2.49 mSv and that in the arms is 1.09 mSv. These results are all in GB18871's annual dose limits on professionals.Although all results of the detection are below the national requirements, the protection awareness can not be taken lightly. With the increase in patient volume, annual number of doing and pumping drugs will gradually increase. So there will always be the possibility of exceeding national regulations. The exposure dose of the pharmaceutical staff is mainly from artificial pumping drugs. As there is no way of providing automatic installation at present, we must take advantage of the three principles of protection at work. First of all, do blank pre-test operations during the gaps of pumping drugs to improve operational proficiency and shorten the exposure time. Secondly, according to the extent of drug decay, choose lead sets of syringes not specification of 2ml and 5ml in order to reduce the exposure dose. Finally, you can apply for a rotation system and each person's continuous drug pumping time can't be more than six months.This study provides reference data for protection of pharmaceutical personnel at PET-CT Center to enhance the protection to reduce occupational exposure.