ABSTRACT
Understanding the spatial distribution of radiation levels outside of a patient undergoing177Lu radioligand therapy is not only helpful for conducting correct tests for patient release, but also useful for estimation of its potential exposure to healthcare workers, caregivers, family members, and the general public. In this study, by mimicking the177Lu-labeled prostate-specific membrane antigen radioligand therapy for prostate cancers in an adult male, the spatial distribution of radiation levels outside of the phantom was simulated based on the Monte Carlo software of Particle and Heavy Ion Transport System, and verified by a series of measurements. Moreover, the normalized dose rates were further formulized on the three transverse planes representing the heights of pelvis, abdomen and chest. The results showed that the distributions of radiation levels were quite complex. Multi-directional and multi-height measurements are needed to ensure the external dose rate to meet the release criteria. In general, the radiation level was higher at the horizontal plane where the source was located, and the levels in front and behind of the body were higher than those of the left and right sides at the same height. The ratio of simulated dose rates to measured ones ranged from 0.82 to 1.19 within 1 m away from the body surface in all directions. Based on the established functions, the relative root mean square deviation between the calculated and simulated values were 0.21, 0.25 and 0.23 within a radius of 1 m on the pelvis, abdomen and chest transverse planes, respectively. It is expected that the results of this study would be helpful for guiding the test of extracorporeal radiation to determine the patient's release, and of benefit to estimate the radiation exposure to others.
Subject(s)
Prostatic Neoplasms , Radiation Exposure , Software , Adult , Humans , Male , Family , Radiotherapy , Lutetium/therapeutic use , Prostatic Neoplasms/radiotherapyABSTRACT
Objective The purpose of this study is to grasp the current situation of radiation protection in some non-medical institutions in Hangzhou, and to provide basis and reference for the relevant authorities departments to make the radioactive hazard factors monitoring plan for non-medical institutions. Methods The configuration of the personnel protective equipment and radiation level of radiation sources and radiation devices in 5 non-medical monitoring institutions in Hangzhou were investigated and analyzed by means of questionnaire survey and on-site detection. Results The radiation workers of 5 monitoring institutions have carried out personal dose monitoring, and their annual individual dose equivalent meets the requirements of relevant national standards. The ambient dose equivalent rates around the radiation source and radiation device room are lower than the minimum detection limit of the instrument. When the source is stored, the maximum ambient dose equivalent rates at 5 cm and 100 cm away from the external surface of the source container were 22.2 μSv/h and 2.0 μSv/h, respectively. When the source is in use, the maximum ambient dose equivalent rates at 5 cm and 100 cm away from the external surface of the source container were 44.3 μSv/h and 5.0 μSv/h, respectively. Conclusion Under normal operation, the radiation dose level of some non-medical monitoring institutions in Hangzhou is at a low level, while the ambient dose equivalent rates around the external surface of the source container is at a high level. Therefore, non-medical institutions should improve their awareness of radiation protection and strengthen radiation management.
ABSTRACT
Objective To study the radiation level in the surrounding of patients undergoing 99Tcm-MDP SPECT bone imaging and associated influencing factors and provide experimental data for the radiation safety of personnel around the patients.Methods A total of 367 patients undergoing whole-body bone imaging in Cancer Hospital,Chinese Academy of Medical Sciences were investigated to measure the ambient dose equivalent rate around the patients at different time and different distances from the patients,analyze the variations of ambient dose equivalent rate with time and distances,estimate the dose level at different distances around the patients,and evaluate the radiation dose to personnel around the patients.Results The ambient dose equivalent rate around the patient decreased exponentially with time;the effective half-life of 99Tcm in patients' body increased with time.The ambient dose equivalent rate varied by power function with increasing distance within 4 meters from the patient with the mean power value of -1.45.The radiation levels were 238.3 μSv at 0.5 m,99.7 μSv at 1 m,and 61.8 μSv at 1.5 m from the patient undergoing 99Tcm injection to its vanishing in patients' body.At different time points,the radiation doses at 0.5 m off the patient for 10 min were:9.9,3.0,1.9 μSv at 0,3 and 6 h,respectively.Conclusions The ambient dose equivalent rate around the patients undergoing 99Tcm-MDP SPECT bone imaging decrease rapidly with increasing time and distance.The patients can cause a certain degree of exposures to the surrounding personnel,but the exposure level is far lower than the relevant national standards.It is suggested that the patients should not receive other types of diagnosis and treatments spending lot of time and in close contact with medical staff while bone imaging being conducted on the same day.
ABSTRACT
The present study aimed to clarify the associations among radiation exposure or psychological exposure to the Fukushima nuclear power plant accident (i.e., fear/anxiety immediately after the accident), current radiation anxiety, and psychological distress among non-evacuee community residents in Fukushima five years after the Great East Japan Earthquake, which occurred in March 2011. A questionnaire survey was administered to a random sample of non-evacuee community residents from 49 municipalities of Fukushima prefecture from February to April 2016, and data from 1684 respondents (34.4%) were analyzed. Environmental radiation levels at the time of the accident were ascertained from survey meter data, while environmental radiation levels at the time of the survey were ascertained from monitoring post data. In the questionnaire, immediate fear/anxiety after the accident, current radiation anxiety, and psychological distress were measured using a single-item question, a 7-item scale, and K6, respectively. Multilevel linear or logistic regression models were applied to analyze the determinants of radiation anxiety and psychological distress. The findings showed that environmental radiation levels at the time of the survey were more strongly associated with radiation anxiety than radiation levels immediately after the accident. Disaster-related experiences, such as direct damage, disaster-related family stress, and fear/anxiety after the accident, and demographic characteristics (e.g., younger age, being married, low socioeconomic status) were significantly associated with radiation anxiety. Environmental radiation levels at the time of the accident or survey were not significantly associated with psychological distress. Radiation anxiety largely mediated the association between fear/anxiety after the accident and psychological distress. In addition to environmental radiation levels, respondents' radiation anxiety was affected by multiple factors, such as disaster-related experiences and demographic characteristics. Radiation levels were not associated with psychological distress in non-evacuee community residents. Rather, fear/anxiety after the nuclear power plant accident may be a determinant of psychological distress, mediated by radiation anxiety.
ABSTRACT
A comprehensive measurement of radioactivity concentrations of the primordial radionuclides 238U, 232Th and 40K and their decay products in the soil samples collected from the sites of Indian research stations, Bharati and Maitri, at Antarctica was carried out using gamma spectrometric method. The activity concentrations in the soil samples of Bharati site were observed to be few times higher than of Maitri site. The major contributor to radioactivity content in the soil at Bharati site is 232Th radionuclide in higher concentration. The gamma radiation levels based on the measured radioactivity of soil samples were calculated using the equation given in UNSCEAR 2000. The calculated radiation levels were compared with the measured values and found to correlate reasonably well. The study could be useful for the scientists working at Antarctica especially those at Indian station to take decision to avoid areas with higher radioactivity before erecting any facility for long term experiment or use.
Subject(s)
Background Radiation , Radiation Monitoring , Radioactive Pollutants/analysis , Antarctic Regions , Expeditions , India , Radioactivity , Radioisotopes/analysis , Spectrometry, GammaABSTRACT
Objective To develop the radiation shielding device for an environmental radiation survey meter with an aim to precisely measure local radiation levels and evaluate decontamination effectiveness in Fukushima.Methods A kind of lead alloy was selected as the main material for the shielding device.Attenuation effects of different lead plates and lead cylinders were measured at the radiation regulatory laboratory and in a polluted area of Fukushima,respectively.The whole shielding device was designed on the basis of measurement results,attenuation effects,cost of production and practicability.Results The whole device was composed of main shielding,probe shielding and a bracket with lid.The main shielding was a lead cylinder with 10 cm in height and 3 cm in thickness.The probe shielding was a lead cylinder with 8 cm in height and 2 cm in thickness.The thickness of lid was 1 cm.Conclusions The device can be available to effectively shield the influence of ambient radiation and accurately measure local radiation levels and evaluate decontamination effectiveness.It can play a valuable part in post-disaster reconstruction of contaminated areas in Fukushima.
ABSTRACT
Objective The rapid development of radiation equipment has put forward higher requirements for protective facil -ities.The aim of this study was to research the radiation protection status of treatment equipment room in thirty -three medical units from East China area , and to put forward corresponding countermeasures to improve the level of radiation protection . Methods The li-cense and archival of X-ray machine, CT, gamma knife, accelerator, after loading therapy machine were surveyed in the thirty-three medical units .The engine room size , wall thickness , lead equivalent of protection doors , and leakage level of equipment were detec-ted.All the data were evaluated and analyzed on the basis of the corresponding national standards . Results ①The inspection pass rates of radiation treatment equipments in the first class hospitals were afterloader (100%), X-ray apparatus(99%), gastrointestinal machine(98%), CT(98%), medical processing accelerator (98%), gamma knife(97%), DSA(94%), PET-CT(94%), ECT (90%), dental engine(84%)and molybdenum target drone (84%).The inspection pass rates of radiation treatment equipments in other class hospitals were medical processing accelerator (100%), X-ray apparatus(91%), CT(89%), gastrointestinal machine (80%), DSA(80%) and (80%) gamma knife.②The qualified rates of the leakage radiation levels of radiation therapy , diagnostic radiology and nuclear medicine were 100%, 99% and 97%. Conclusion The radiation protection of treatment equipments and facilities in thirty-three medical units from East China area needs to be strengthened . We should strengthen supervision , implement the rules and regulations , strictly perform the regulation of radiation protection evalua-tion, and strengthen the training of radiation protection regulations and skills .
ABSTRACT
Objective To study the effect on the environmental radioactivity level and the health of the residents in Shanghai when Qinshan Nuclear Power Station(QNPS) has been in normal operational condition for 17 years. Methods The field monitoring and the sampling analytical method were used for monitoring the radioactivity level in outdoor environment, drinking water, food and soil. Results The outdoor natural radiation level and the radioactivity level in the sample of the environmental media were on the normal background level. There was no distinct change in the environmental radiation level of Jinshan Area when QNPS was in normal operational condition. The radioactivity level in the environmental media was far lower than the limit values specified by the national standard GB. The effective dose of the outdoor natural external exposure for the residents is about 0.102 mSv/a and the effective dose of the internal exposure from the artificial radionuclides 90Sr and 137Cs in food for the residents is about 0.488 μSv/a. Conclusions There is no effect of the radioactive contamination on the environmental radioactivity level and the health of the residents in Shanghai when QNPS has been in normal operational condition for 17 years.
