• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2428-2435
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• 2024

Training for radiation protection and control requires a visual understanding of radiation, which cannot be perceived by the human senses. Trainees must also master the effective use of measuring instruments. Traditionally, such training has exposed trainees to radiation sources. Here, we present a novel e-training strategy that enables safe, exposure-free handling of a radiation measuring tool called a survey meter. Our mixed reality radiation-training system merges the physical world with a digital one. Collaborating with a mixed reality headset (HoloLens 2), this system constructs a mock-up of a survey meter in real-world space. The HoloLens 2 employs a browser-based application to visualize radiation and to simulate/share the use of the survey meter, including its physical movements. To provide a dynamic learning experience, the system adjusts the survey-meter mock-up readings according to the operator's movements, distance from the radiation source, the response time of survey meter, and shielding levels. Through this approach, we expect that trainees will acquire practical skills in interpreting survey-meter readings and gain a visual understanding of radiation in real-world situations.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.1
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• pp.1-8
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• 1971

A survey meter which is used a G-M counter sensitive to beta and gamma radiation is studied. This device is completely transistorized, operated with battery, and can be read directly the 3 full-scale meter range: 2.5, 25 and 250 MR/HR respectively. The collector-coupled monostabel multivibrator consisting of a counting-rate meter circuit, and the astable blocking oscillator consisting of a dc-de converter for power supply are analyzed and derived the design dquations. To improve the resolving time of the G-M counter the device is designed to be triggered by low pulse in the order of 0.5v.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.25-28
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• 2011

Purpose: The aim of study is to find accuracy of pocket dosimeter in measuring exposed dose in compared with survey meter and to compare exposed dose according as Nuclear medicine exams. Materials and Method: First, radiation dose to point source(185 MBq,370 MBq, ${\ldots}$, 1665 MBq, 1850 MBq) were measured in using a pocket dosimeter and a survey meter. Second, radiation dose to 12 patients injected $^{18}F$-FDG 370 MBq were measured in using a pocket dosimeter and a survey meter. Third, radiation dose to 10 patients injected $^{99m}Tc$-DPD 925 MBq were measured in using a pocket dosimeter and a surveymeter. Result: The average is $70.12{\pm}39.36{\mu}Sv/h$ in measurement of point source with Surveymeter and $5{\pm}3.06{\mu}Sv$ in measurement of point source with Pocket dosimeter. The average is $25.04{\pm}6.16{\mu}Sv/h$ in measurement of PET/CT patients with Surveymeter and $2.41{\pm}0.51{\mu}Sv$ in measurement of PET/CT with Pocket dosimeter. The average is $8.58{\pm}0.96{\mu}Sv/h$ in measurement of Bone Scan patients with Surveymeter and $1{\mu}Sv$ in measurement of Bone Scan patients with Pocket dosimeter. Significant difference found between Survey meter value and Pocket dosimeter value in all experimentation (p<0.001). Conclusion: Accoring to rusult Wearing Pocket dosimeter is usefulnee in manerage of exposed dose in nucler medicine exams.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.50-56
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• 2012

Purpose: Those who access to the nuclear medicine department are classified as radiation workers, temporarily access group, and occasional access group as defined by the atomic energy law. The radiation workers and temporarily access people wear a personal radiation dosimeter for checking their own radiation absorbed dose periodically. However, because of the sanitation workers, classified as temporarily access group, who are working in the nuclear medicine department are moved in a cycle with other departments and their works are changeful, it is hard to control their radiation absorbed dose. Thus, this study is going to examine the state of the sanitation worker's radiation absorbed dose, and then make sure whether they are classified as temporarily access group or not. Materials and methods: In the first instance, the first sanitation worker who works in vitro laboratory and PET room and the second sanitation worker who works in gamma camera rooms (invivo room) wore radiation dosimeter-OSL(Optically Stimulated Luminescence)- to measure their own radiation absorbed dose during work time from May to June 2011. Secondly, this study was taken place 5 places in gamma camera rooms, 2 places in PET bed room, operating room, waiting room and cyclotron room in PET and 4 places in vitro laboratory. And then to measure the radiation space dose rate, it is measured 10 times each of places as sanitation worker's work flow by using radiation survey meter. Results: The radiation absorbed dose on OSL of the first c who works in vitro laboratory and PET room and the second one who works in gamma camera rooms are 0.04, 0.02 mSv per month respectively. That means the estimated annual radiation absorbed doses are less than 1mSv as 0.48, 0.24 mSv/yr respectively. The radiation space dose rates as sanitation worker's work flow using survey meter are 0.0037, 0.0019 mSv/day, so the estimated annual radiation absorbed dose are 0.93, 0.47 mSv/yr respectively. The weighted exposure dose of first sanitation worker of each places are 1.62% in cyclotron room, 3.88% in waiting room, 2.39% in operating room, 81.01% in bed room of PET and 11.01% in vitro laboratory. The weighted exposure dose of second sanitation worker of each places are 45.22% in radiopharmaceutical laboratory, gamma 30.64% in camera rooms, 15.65% in waiting room, 8.49% in reading room. Conclusion: The annual radiation absorbed doses on OSL of both sanitation workers are less than 1 mSv per year and the annual radiation absorbed doses by using survey meter are less than 1mSv either, but close up to 1 mSv. Thus, to clarify whether the sanitation workers are temporarily access group or not, and to be lessen their s radiation absorbed dose, they should be educated about management of radiation and modified their work flow or work time appropriately, their radiation absorbed dose would be lessen certainly.

• Journal of Radiation Protection and Research
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• v.48 no.3
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• pp.131-143
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• 2023

Background: This study examined the detection limit of thyroid screening monitoring conducted at the time of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 using a Monte Carlo simulation. Materials and Methods: We calculated the detection limit of a NaI(Tl) survey meter to measure ¹³¹I accumulation in the thyroid gland of children. Mathematical phantoms of 1- and 5-year-old children were developed in the simulation of the Particle and Heavy Ion Transport code System code. Contamination of the body surface with eight radionuclides found after the FDNPP accident was assumed to have been deposited on the neck and shoulder area. Results and Discussion: The detection limit was calculated as a function of ambient dose rate. In the case of 40 Bq/cm² contamination on the body surface of the neck, the present simulations showed that residual thyroid radioactivity corresponding to thyroid dose of 100 mSv can be detected within 21 days after intake at the ambient dose rate of 0.2 µSv/hr and within 11 days in the case of 2.0 µSv/hr. When a time constant of 10 seconds was used at the dose rate of 0.2 µSv/hr, the estimated survey meter output error was 5%. Evaluation of the effect of individual differences in the location of the thyroid gland confirmed that the measured value would decrease by approximately 6% for a height difference of ±1 cm and increase by approximately 65% for a depth of 1 cm. Conclusion: In the event of a nuclear disaster, simple measurements carried out using a NaI(Tl) scintillation survey meter remain effective for assessing ¹³¹I intake. However, it should be noted that the presence of short-half-life radioactive materials on the body surface affects the detection limit.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.741-749
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• 2022

Radiography-Testing that verify the quality of welding structures without destruction are overwhelmingly used in industries, but many safety precautions are required as radiation is used. The workers for Radiography-Testing perform the inspection by moving the Iridium-192 radiation source embedded in the transport container of the gamma-ray irradiator within or outside the facility. The general facility is completely blocked about radiation from the outside with thick concrete, but if it is difficult for worker to handle object of inspection, facilities ceiling can be opened. A general facility may be constructed using a theoretical dose evaluation method because all exterior facilities are blocked, but if the ceiling is open, it is not appropriate to evaluate radiation safety with a simple theoretical calculation method due to the skyshine effect. Therefore, in this study, the radiation safety of the facility was evaluated in the actual field through an ion chamber survey-meter and an accumulated dose-meter called as OSLD, and the actual evaluation environment was modeled and evaluated using the Monte Carlo simulation code as FLUKA. According to the direction of the irradiation, the radiation dose at the facility boundary was difficult to meet the standards set by the regulatory authority, and radiation safety could be secured through additional methods. In addition, it was confirmed that the simulation results using the Iridium-192 source were valid evaluation with the actual measured results.

• Progress in Medical Physics
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• v.27 no.1
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• pp.46-53
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• 2016

Periodical calibrations of radiation detectors are important for accurate quality assurance of therapeutic linac. The measuring instruments such as ion-chamber, thermometer, barometer, and survey meter should be calibrated periodically. Period of calibration for these instruments is suggested 6 month to one year in Korea and two years in other countries nowadays. Therefore, the determination of reasonable period for calibration is needed. In this study, we plan to utilize the results of these survey; frequent in use, how to use and stability of instruments, to determine the optimized period of calibration for the instruments in the departments of radiation oncology in Korea based on the ILAC-G24. The SurveyMonkey web-based survey tool was used and the objects of survey were 18 department of radiation oncology in university hospitals, and 15 departments were answered. The 64 questionnaires which supposed to be answered in 50 minutes were classified as the information of candidates, the thermometer, the barometer, the surveymeter, and the ion-chamber. The thermometers and the barometers were not under periodical calibration for more than half of candidates. The periods of calibration of surveymeters were 6 month to 1 year. We expect that the calibration period can be determined based on these survey results.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.2
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• pp.69-79
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• 2004

In the process of photon treatments, linear accelerators with energies higher than 10 MV produce neutrons through the (${\gamma}$, n) interactions with the composite materials of the linac head md these materials further produce the induced radiations. We investigate the possible risks from these induced radiations especially in the wedge filters to the radiation workers. Wedge filters are used to modify the isodose profiles in the radiation treatment using the linear accelerator and always be handled by the radiation workers. For the background radiation, we measured the radiation in both the waiting room and the outside of the building for two hospitals, S and H. The results of S hospital were $0.11\;{\mu}Sv/hr$ and $0.10\;{\mu}Sv/hr$ for waiting room and outside respectively, and in the case of H hospital, they were $0.12\;{\mu}Sv/hr$ and $0.11\;{\mu}Sv/hr$. Using a survey meter, we measured the radiation from wedge filters inserted in 10 MV and 15 MV Siemens linear accelerators. The time series measurements were done in ${\sim}1$ minutes after exposure of 5 Gy of monitor units for the field size of $25{\times}25cm^2$. The starting value of 10 MV machine was about $3.26\;{\mu}Sv/hr$, which was three times higher than that of 10 MV. The measured radiation was from $^{28}Al$ and $^{53}Fe$ with a half life of 3.5 min. If the treatment patients are $20{\sim}50$ per day and the number of process of wedge filter change per patient is one or two, the annual dose equivalent is $0.08{\sim}0.4\;mSv$ for 10 MV, and $0.27{\sim}1.36\;mSv$ for 15 MV, which are in the range of dose equivalent limits of radiation workers.

• Journal of radiological science and technology
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• v.47 no.1
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• pp.13-19
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• 2024

Control of scattered radiation is one of very important factors in the use of medical radiation. In general X-ray exam, the causes, measurement methods, and the kind of detectors of scattered rays within the radiation area are diverse. In this study, the dose of scattered ray was measured by changing the thickness of the polycarbonate phantom and the tube voltage. As a result of measurement of scattered radiation, the results show that the scattered dose significantly(p<.05) increased with growing of thickness of phantom in the tube voltage 40, 50 and 60 kVp(F(p)<.05, R²>64%). As tube voltage increased at all phantom thicknesses, the scattered dose also significantly(p<.05) increased(F(p)<.05, R²>69%). In cases where a significant correlation was shown, the coefficient of determination of more than 60% was shown in regression analysis. The results of this study can be used as data on scattered radiation dose according to the tube voltage and the object thickness in general X-ray imaging exam.

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.77-83
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• 2021

The purpose of the study is to evaluate the effect on medical application and convergence for the efficient disaster responses in the massive radiological events by comparison of two types of survey-meters(hand held survey-meter and transportable portal monitor). In the simulated radiation disaster drill, twelve participants randomly wore a personal protective equipments (PPE) with twelve check source. We measured participants to detect five real radioactive sources of the twelve check sources, using two types of survey meters. The primary outcome was the measuring time. The secondary outcome was the sensitivity and specificity of the detection of the real radioactive source. The average time by the hand held survey meter was 231.9 ± 116.6 seconds, and the time by transportable portal monitor was statistically shorter 8.690 ± 1.667 seconds. There was no difference in the sensitivity and specificity between two survey meters. The transportable portal monitor survey meter was considered to have medical application and play an important role in radiological disasters.