Study On Radiation Dose Of Medical Staff And Optimization Of Radiological Protection Management In Iodine-125 Seed Implantation Ward

BackgroundIodine-125(¹²⁵I) seed implantation therapy is a new and effective treatment of malignant tumors that the greatest degree of anti-tumor tissue suffered with micro continuous short-distance radioactive sources implanted.¹²⁵I seed implantation therapy is less invasive, locally high-dose, clearly effective and with less adverse reaction, so that it has become a wide range of clinical applications in many medical institutions for the treatment of localized prostate cancer, liver cancer, lung cancer, gallbladder cancer, pancreatic cancer, osseous metastasis and many other malignancies. The continuously low energy gamma rays from ¹²⁵I seed source can destroy tumor cells and fracture the double-stranded DNA, making the tumor cells losing the ability of proliferation and achieving its therapeutic effect. With the wide application of this therapy, the medical staff and the public paid more and more attention to problems of radiation safety. Studies have shown that long-term low-dose radiation ray have a certain impact on the medical staff’s thyroids, sexual organs, and the eye lens, leading thyroid and sexual function loss and sperm count reducing and crystalline lens damaging, as well as the influence on intelligence and memory, increasing the incidence of leukemia and malignant tumor.How to manage the radiation protection after ¹²⁵I seed implantation? As we all know the three big basic principles of radiation protection includes time protection, distance protection and shielding protection. Time protection refers that the cumulative dose of irradiation on human body is proportional to the irradiated time no matter what irradiation type is. The longer the time exposure, the more severe harm is. Distance protection refers that the irradiation dose rate on the human body is inversely proportional to the square of the distance, namely the dose rate would reduce to a quarter as the distance become double as the origin. The shielding protection refers to using protective barriers which contain strong absorption and reducing effect of irradiation to reduce the exposure to human body. When the protective barrier is located between the irradiative source and the human body, the radiation dose on human body can reduce effectively. At present, it is a lead shielding coverage or a wearing protective clothing for patients that used to reduce the irradiative damage on medical staff from the source implanted in the patients in most of the medical institutions or hospitals. At the same time, a wearing protective clothing for the medical staff is also an effective method to avoid unnecessary irradiative harm to human body, of which shielding efficiency can be 90%～95%.It is a pop topic and attentive question on how to protect the health of professional irradiative staff as much as possible in recent years. And the irradiative protection and personal dose monitoring is an important assurance for the health of irradiative staff and is also one of the vital contents of the irradiative safety and protection work. The monitoring of personal dose is to monitor the cumulative dose external exposure on medical staff, of which data could be the standard to evaluate the damage of irradiation and its extent. It can also be used to know the health status of the staff, improving the working type and reducing unnecessary radiation by taking timely measurements. The monitoring of personal dose remains vital important position in occupational health management for irradiative staff. At present, more relevant research reports were on radiation workers radiological protection but less on medical staff of ¹²⁵I seed implantation ward, even no reports about research and analysis of the accurate irradiative dose on medical staff and the comparison study about the different irradiative dose between the medical staff working in or out of the irradiative ward.Objectives1.To compare the different irradiative dose between the staff working in or out of the irradiative ¹²⁵I seed ward and evaluate the safety of the irradiative ¹²⁵I seed ward to eliminate the fear of the medical staff.2.To observe the irradiation safety and the management of irradiative protection to focus on the irradiation to the nurses working in irradiative ¹²⁵I seed ward.3.To optimize the management of the irradiative protection on the basis of the original measurements and to provide methods for protection of the medical staff working in irradiative ¹²⁵I seed ward.MethodsThe patients from Minimally Invasive Interventional Therapy and nasopharynx department of Sun Yat-sen University Cancer Center from April,2014 to September, 2015 were enrolled in this study. The inclusive criteria are the staff working in irradiative ¹²⁵I seed ward who is health and voluntary and can be extracted at any time during the study period. The exclusive criteria include pregnant, having a more than a month vacation during the study, going abroad or education for more than a month during the study and who is not willing to participate. According to inclusive and exclusive criteria, a total of 63 medical staffs from minimally invasive interventional and nasopharyngeal department were enrolled in this study, which is then divided into exposure group and non-exposed group, in which the exposed group contained 25 medical staff working in irradiative ¹²⁵I seed ward in minimally invasive interventional department, including 10 male workers and 15 female workers. There are 38 people in non-exposed group including 10 male workers and 28 female workers from nasopharyngeal department. There is no difference between two groups.Using the thermoluminescent dosimeter （TLD） to monitor the radiation dose of ¹²⁵I seed implantation ward staff and non-¹²⁵I seed implantation ward staff in our center. Quarterly periodic replacement of the dosimeter, the old were sent to a third-party testing organization for data read by the medical service. A total of six quarters of single-quarter dose data was read during the study period （April 2014 to September 2015）, and calculate the total dose. Analyze the radiation dose difference between 1251 seed implantation ward and non-¹²⁵I implantation ward, and the difference between ¹²⁵I seed implantation ward and the Basic standards for protection against ionizing radiation and for the safety of radiation sources （hereinafter referred to as "GB"）, and to compare the radiation dose of doctors with nurses. From the fourth quarter of 2015, the management of radiological protection equipment and utensils and medical operating classification system has been optimized in ¹²⁵I seed implantation ward. Read the medical radiation dose data of the fourth quarter of 2015, and compared with the former six quarter, then analyzed the differences.StatisticsThe data of parameters with normal distributions are reported as mean and standard deviations. The Independent sample t test was employed to compare the data between two groups. The one sample t test was used to compared with the results to international standard and the paired sample t test was used to compare the data before and after the optimization of irradiative protective measurements. Alpha was set at 0.05, and all tests were two-tailed. All data were analyzed with the SPSS 19.0 statistical software （Chicago, IL, USA）.Results1. Comparing the ¹²⁵I seed implantation ward wih non-¹²⁵I seed implantation ward, The sum of six quarters radiation dose in ¹²⁵I implantation ward staff was greater than the non-¹²⁵I implantation ward （t= 7.42, p= 0.00）. The mean medical staff radiation dose in ¹²⁵I seed implantation ward was greater than non-I25I implantation ward in each single quarter（p<0.05）, except the fourth quarter of 2014 （t= 0.35, p> 0.05）; There was no Significant differences between the doctors’ insingle quarter radiation dose in ¹²⁵I implantation ward and non-¹²⁵I implantation ward. The doctors’radiation dose of ¹²⁵I seed implantation ward was greater than those of the non-¹²⁵I seed implantation ward in the second and the third quarter of 2014 as well as the second quarter of 2015（p<0.05）. But in the fourth quarter of 2014（t=-0.67,p=0.51）, the first quarter of 2015 （t=0.31,p=0.76） and the third quarter of 2015 （t=1.70,p=0.12）, there was no difference between 1251 seed implantation ward doctors and the non-1251 seed implantation ward doctors; The nurses’ single quarter radiation dose in ¹²⁵I seed implantation ward was greater than those in the non-1251 seed implantation ward（p<0.05）,except the fourth quarter of 2014 （t=1.55,p=0.13）.2. Medical staff radiation dose of each quarter in ¹²⁵I seed implantation ward were lower than the GB （p<0.05）; The doctors’single quarter radiation dose were lower than the GB （p<0.05）; The nurses’single quarter radiation dose were lower than the GB in the second quarter of 2014（t=-6.62,p=0.00） and the third quarter of 2015（t=-5.23,p=0.00）, but there were no statistical significance in all the other four quarters （p>0.05）.3. Comparing the doctors with the nursrs, The sum of ¹²⁵I seed implantation dcotor radiation dose was lower than the nurses （t=-10.05, p=0.00）. The doctors’ single quarter radiation dose in ¹²⁵I seed implantation were greater than the nurses （p<0.05） in all quarters except the second quarter of 2014 （t=-0.33,p=0.75）.There was no difference between doctors and nurses’ totle radiation dose in the non-¹²⁵I implantation ward （t=-1.84, p=0.07）. Comparing the doctors’ single quarter radiation dose with the nurses, the difference was not great in all quarters except the fourth quarter of 2014 in with the docrors’ dose were lower than the nurses （t=-2.61,p=0.01）4. After the implementation of optimization of radiological protection management in ¹²⁵I implantation ward, the radiation dose of the fourth quarter of 2015 in the nurses group was less than the mean radiation dose of the former six quarters （t=5.15, p=0.00）, but no difference in doctors group （t= 1.86, p=0.10）.Conclusions1. The staff’s totle radiation dose in ¹²⁵I seed implantation ward was greater than non-¹²⁵I seed implantation ward. The difference of the doctors’insingle quarter radiation dose in the two ward was not great, but the nurses’insingle quarter radiation dose in ¹²⁵I seed implantation ward were much greater than those in the non-¹²⁵I seed implantation ward. So it is sure that the radiation is existing in the ¹²⁵I seed implantation ward. We should continue to improve awareness of radiological protection, perfect the management system, optimize workflows in wards, and strengthen radiological protection measures.2. The doctors’radiation dose was lower than GB, well there was no great difference between the nurses’dose and GB except two quarter. So it is still need to be disscuss that if the work environment in ¹²⁵I seed implantation ward is safe or not. The hospital management departments should strengthen the recognition of nurses working on radiological protection with perfecting protective equipment and utensils, strengthening protection knowledge training, and organizing regular physical examination and so on.3. Making careful health-care plan is very important to the nurses in ¹²⁵I seed implantation ward, with contacting patients for a long time in a short distance with radiation dose. So the nurses need skilled operation technology. We shoud develop a thorough plan according to the characteristics of the treatment and the needs of patients. It is also very important for us to do prefect preparation and to equipe with safety protective equipment before operation., well during the operation we should reduce the irradiation time and keep a certain operating distance. Only by constantly improve the self protection consciousness,we can provide good service for patients as well as protect ourselves.4. The implementation of optimization of radiological protection management can effectively reduce radiation dose of the nurses in ¹²⁵I seed implantation ward, but not to the doctors. The management of radiological protection equipment and utensils and medical operating classification system has effect on nurses. But the management should still to be further optimized.