PURPOSE: The purpose of this study was to measure the absorbed dose and to calculate the effective dose for periapical radiography done by portable intraoral x-ray machines. MATERIALS AND METHODS: 14 full mouth, upper posterior and lower posterior periapical radiographs were taken by wall-type 1 and portable type 3 intraoral x-ray machines. Thermoluminescent dosemeters were placed at 23 sites at the layers of the tissue-equivalent ART woman phantom for dosimetry. Average tissue absorbed dose and radiation weighted dose were calculated for each major anatomical site. Effective dose was calculated using 2005 ICRP tissue weighted factors. RESULTS: On 14 full mouth periapical radiographs, the effective dose for wall-type x-ray machine was 30 Sv; for portable x-ray machines were 30 Sv, 22 Sv, 36 Sv. On upper posterior radiograph, the effective dose for wall-type x-ray machine was 4 Sv; for portable x-ray machines doses were 4 Sv, 3 Sv, 5 Sv. On lower posterior radiograph, the effective dose for wall type x-ray machine was 5 Sv; for portable x-ray machines doses were 4 Sv, 4 Sv, 5 Sv. CONCLUSION: Effective doses for periapical radiographs performed by portable intraoral x-ray machines were similar to doses for periapical radiographs taken by wall type intraoral x-ray machines.
Diagnostic Imaging ; Female ; Humans ; Mouth ; Radiation Monitoring ; Radiography* ; Radiography, Dental ; Radiometry ; Thermoluminescent Dosimetry

The paper is focused on a kind of portable monitor that is widely used in military hospitals. In order to study the electromagnetic radiation immunity of the monitor, the experiments of electromagnetic radiation caused by radio frequency continuous wave in reverberation chamber and by ultra wide band (UWB) electromagnetic pulse have been done. The study results show that UWB electromagnetic pulse interferes observably the operating state of the monitor. It should be paid high attention to take protective measures. The monitor tested has some electromagnetic immunity ability for radio frequency continuous wave radiation. The frequent abnormal phenomena are baseline drift and waveform distortion. The electromagnetic sensitivity of the monitor is related to the frequency of interference source. The monitor tested is most sensitive to the frequency of 390 MHz.
Electromagnetic Fields ; Electromagnetic Radiation ; Monitoring, Physiologic ; instrumentation

OBJECTIVEThis work explores the diurnal variation of Solar ultraviolet radiation (UVR) and total solar radiation (TSR) in northeast China, using daily observations of UVR and TSR in Shenyang.

METHODSUVR and TSR measurements were carried out from March 1st, 2006 to December 31st, 2009 in Shenyang, Liaoning province, China (41°51' N, 123°27' E).

RESULTSBoth TSR and UVR showed seasonal variation, reaching the highest levels in summer and the lowest in winter. They showed the greatest fluctuation in summer and autumn. The irradiance of TSR and UVR on clear days around the equinoxes and solstices increased substantially compared with the mean seasonal irradiance, especially in autumn. The whole day accumulated dose of UVR in winter was far less than that during the middle part of a summer day (i.e. between 10:00 and 14:00). It was also less than the accumulated summer dose of morning and afternoon (i.e. between 8:00 and 10:00 and 14:00 and 16:00).

CONCLUSIONThe instant irradiance and daily accumulated amount of UVR are low in Shenyang, especially in autumn and winter. Thus concern about the health effects arising because shortage of UVR in northeast China is warranted.

For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.
Clothing ; Gamma Rays* ; Isotopes ; Radiation Monitoring ; Semiconductors

Radiation exposure during fluoroscopy has been of consistent interest because fluoroscopy is used not only for diagnostic purposes such as upper gastrointestinal series but for many minimally-invasive treatments in various clinical fields. In 2000, the International Commission on Radiological Protection published the important report about the avoidance of radiation injuries from medical interventional procedures, and this report defined harm during fluoroscopic-guided interventional procedure and how to reduce the radiation dose of patients and staff. Two aspects of fluoroscopy exposure differ from other types of medical radiation exposure, including computed tomography. One is that the entrance surface dose during an interventional procedure may be very high, so the deterministic effects of radiation such as skin or corneal injury should be emphasized more than stochastic effects such as cancer risk. The other is that the variation in radiation exposure is great for the same kind of procedure, so it is very difficult to generate a reference level for the radiation dose. Therefore, it is necessary to develop a guideline for the use of fluoroscopy through a nationwide survey about irradiation during fluoroscopic examinations and fluoroscopy-guided intervention procedures. In conclusion, radiation exposure by fluoroscopic guided intervention is not negligible, and the practitioner should always aim to reduce radiation exposure during interventional procedures.
Fluoroscopy ; Humans ; Radiation Dosage ; Radiation Injuries ; Radiation Monitoring ; Radiography, Interventional ; Radiology, Interventional ; Skin

In order to improve the diagnostic quality of X-ray device and to promote the implementation of radiation protection in accordance to the ICRU definition and ICRP classification standards for measuring radiation harm to human body, we have made a number of tests, including the kinetic energy released by ionizing air, the Half-value layer, the output dose coincidence, the High contrast resolution, the Consistency between visual light field and project X-ray field, and the Focus of X-ray tube. We have also analysed the measured data and results. The tests were conducted on the XEB150L-20 made by Shimadzu Co. in the middle of 1990s.
Quality Control ; Radiation Dosage ; Radiation Monitoring ; methods ; Radiation Protection ; methods ; Radiography ; instrumentation ; Radiometry ; methods

BACKGROUND: The C-arm fluoroscope is known as the most important equipment in pain interventions. This study was conducted to investigate the completion rate of education on radiation safety, the knowledge of radiation exposure, the use of radiation protection, and so on. METHODS: Unsigned questionnaires were collected from the 27 pain physicians who applied for the final test to become an expert in pain medicine in 2011. The survey was composed of 12 questions about the position of the hospital, the kind of hospital, the use of C-arm fluoroscopy, radiation safety education, knowledge of annual permissible radiation dose, use of radiation protection, and efforts to reduce radiation exposure. RESULTS: In this study, although most respondents (93%) had used C-arm fluoroscopy, only 33% of the physicians completed radiation safety education. Even though nine (33%) had received education on radiation safety, none of the physicians knew the annual permissible radiation dose. In comparing the radiation safety education group and the no-education group, the rate of wearing radiation-protective glasses or goggles and the use of radiation badges or dosimeters were significantly higher in the education group. However, in the use of other protective equipment, knowledge of radiation safety, and efforts to reduce radiation exposure, there were no statistical differences between the two groups. CONCLUSIONS: The respondents knew very little about radiation safety and had low interest in their radiation exposure. To make the use of fluoroscopy safer, additional education, as well as attention to and knowledge of practices of radiation safety are required for pain physicians.
Surveys and Questionnaires ; Eye Protective Devices ; Eyeglasses ; Fluoroscopy ; Glass ; Surveys and Questionnaires ; Radiation Monitoring ; Radiation Protection

PURPOSE: The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. MATERIALS AND METHODS: An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. RESULTS: The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. CONCLUSION: A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose.
Cone-Beam Computed Tomography ; Dental Clinics ; Dentists ; Humans ; Methods ; Radiation Dosage ; Radiation Monitoring ; Radiography ; Radiography, Dental*

OBJECTIVETo explore the dose-length product calibration method for pencil ionization chamber in cobalt beams.

METHODSThe PTW TM30009 ionization chamber was placed into the central hole of T40017 head phantom and irradiated 60 s in 20 cm x 20 cm cobalt beam. The charge was collected with UNIDOS electrometer. Absorbed doses were measured with TM30013 0.6 mL farmer-type chamber under the same condition. The CT chamber calibration factor was expressed in dose-length product. Dose linearity and spatial response were also investigated.

RESULTSThe calibration factor in dose-length product was derived from measured data. Dose linearity and spatial response were good in cobalt beams.

CONCLUSIONIt is feasible to calibrate the CT chamber in cobalt beams for patient dose evaluation in MVCT.

Objective: To investigate the individual external dose level of some interventional radiology staffs from 2016 to 2020 in Tianjin City. Methods: All 2068 interventional radiology staffs who were included in the work of the Radiation Monitoring Project from 2016 to 2020 were selected as study subjects in March 2021. The individual dose monitoring results of interventional radiology staffs of different ages, working years, time and medical institutions were analyzed. Results: Among 2068 interventional radiology workers, 1406 (67.99%) were male and 662 (32.01%) were female. The age was 44.6 (39.2, 50.3) years, and the working years was 10.5 (4.3, 14.6) years. The annual effective doses per capita of 40-49 age group and ≥50 age group were higher than that of 30-39 age group (P<0.05) . The annual effective dose per capita of 5-9 working years was higher than that of <5 working years, and the annual effective dose per capita of 10-29 working years was higher than that of 5-9 working years (P<0.05) . The median per capita annual effective dose of the interventional radiology staffs was 0.164 mSv. There were 1976 interventional radiology staffs with an annual effective dose of <0.50 mSv/a (95.6%) . The collective dose distribution ration SR(0.5) was 41.1%. The difference of effective dose per capita in each year was statistically significant (H=19.23, P<0.05) . The per capita annual effective dose of interventional radiology staffs in tertiary medical institutions was higher than that in secondary medical institutions, and the difference was statistically significant (P<0.05) . Conclusion: The personal dose of interventional radiology staffs in Tianjin City is at a low level. It is necessary to emphasize the radiation hazard protection of interventional radiology staffs in tertiary medical institutions, 40-49 years old, ≥50 years old age groups and 5-9, 10-29 working years groups.
Adult ; Female ; Humans ; Male ; Middle Aged ; Occupational Exposure/prevention & control* ; Radiation Dosage ; Radiation Monitoring/methods* ; Radiation Protection ; Radiology, Interventional