• Radiation Oncology Journal
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• v.16 no.2
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• pp.115-123
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• 1998

Purpose : This study was tried to evaluate the effect of the partial body fractionated irradiation on the frequency of chromosomal aberration. Materials and Methods : In three patients with uterine cervix carcinoma, chromosomal aberrations were analyzed during fractionated external beam radiotherapy Radiation field included whole pelvis and total dose was 5040 cGy in 28 fractions. Results : The values of the frequency of dicentrics and rings (Ydr) in pre-irradiated peripheral lymphocytes in three patients were 0.0060, 0.0000, and 0.0029, respectively. The frequency of dicentrics and rings, estimated during the course of radiotherapy, increased with radiation dose and best fitted to the linear equation, $Ydr=7.31{\times}10^{-5}D(cGy)+1.45{\times}10^{-2}$. The frequency of dicentrics and rings among the cells with dicentric and/or ring(Qdr) also showed increasing tendency and best fitted to the linear equation, $Qdr=1.01{\times}10^{-4}D(cGy)+1.04$. Conclusion : Ydr increased linearly with radiation dose in the dose range of our study, and Qdr showed increasing tendency with dose.

• Nuclear Engineering and Technology
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• v.26 no.3
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• pp.381-388
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• 1994

Recently, the American National Standards Institute (ANSI) had made some changes in the radiation sources specified from those in the original performance test criteria ANSI N13. 11-1983. In case or beta category, in addition to the high-energy $^{90}$ Sr/$^{90}$ Y beta source, the $^{204}$ Tl source was added because many workplaces have significant levels of lower energy betas. In this study, the performance or the Teledyne PB-3 personnel dosimetry system in the fields of $^{204}$ Tl and $^{90}$ Sr/ $^{90}$ Y beta was investigated using the PTB beta secondary standard sources. The new beta correction function of PB-3 personnel dosimetry system for $^{204}$ Tl beta was also developed in this response experiment. The results show that the Teledyne PB-3 personnel dosimetry system is very effective for $^{90}$ Sr/ $^{90}$ Y beta dose assessment. In case of $^{204}$ Tl beta radiation, however, the results of simple performance test indicated that the use of beta correction factor(=2.088) which was recommanded by manufacturer may result in unexpectable overestimation of delivered dose by about 60%, while the use of developed beta correction function could measure the delivered doses in errors of 15%.

• Progress in Medical Physics
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• v.20 no.1
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• pp.37-42
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• 2009

Proton therapy facility, which is recently installed at National Cancer Center in Korea, generally produces a large amount of radiation near cyclotron due to the secondary particles and radioisotopes caused by collision between proton and nearby materials during the acceleration. Although the level of radiation by radioisotope decreases in length of time, radiation exposure problem still exists since workers are easily exposed by a low level of radiation for a long time due to their job assignment for maintenance or repair of the proton facility. In this paper, the working environment near cyclotron, where the highest radiation exposure is expected, was studied by measuring the degree of radiation and its duration for an appropriate level of protective action guide. To do this, we measured the radiation change in the graphite based energy degrader, the efficiency of transmitted beam and relative activation degree of the transmission beam line. The results showed that while the level of radiation exposure around cyclotron and beam line during the operation is much higher than the other radiation therapy facilities, the radiation exposure rate per year is under the limit recommended by the law showing 1~3 mSv/year.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.1
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• pp.53-59
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• 2004

A variety of factors such as the pattern of intake (acute or chronic), monitoring interval and the characteristics of the radionuclides could have a significant influence on the estimates for the intake and internal dose. The relative differences of the assessed intakes based on the assumption of an acute intake to that of a chronic intake were evaluated by using the predicted bioassay quantity in the whole body or organs for an acute and chronic intake through the inhalation of $^{125}$ I, $^{137}$ C, $^{235}$ U with the AMAD of 1 ${\mu}{\textrm}{m}$ and 5 ${\mu}{\textrm}{m}$ for the monitoring intervals of 7, 14, 30, 60, 90, 120, 180, 360 days, respectively, The relative difference of the assessed intakes based on the intake pattern is affected by the monitoring interval, radionuclide and absorption type, but the particle size has little influence on the difference of the assessed intakes based on the intake pattern. The maximum monitoring interval, which is defined as the monitoring interval that the relative difference of the assessed intakes based on the assumption of an acute intake to that of a chronic intake is less than 10%, is 60 d for $^{125}$ I with Type F, 180 d for $^{137}$ C with Type F, 90 d for $^{235}$ U with Type M, and 360 d for $^{235}$ U with Type S. It was concluded that an intake pattern has little influence on the estimates of the assessed intake in the case where the monitoring interval is shorter than the maximum monitoring interval for each radionuclide.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.79-99
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• 2015

Participants of this study were students of radiology who were attending colleges or universities located in Daegu and Gyeongbuk. This researcher conducted a questionnaire survey of those students from Feb. 3rd to 21st, 2014. The findings of the study can be summarized as follows. 1. Concerning the knowledge of radiation exposure management, the respondents' scores were highest in two items, or 'Materials based on lead or concrete may shield X-rays' and 'The sexual gland is very sensitive to radiation' and lowest in the item which says' 'Occupational radiation exposure dose should not exceed 20mSv a year in average on a 5-year period basis'. 2. The participants' scores for the attitudes of radiation exposure management were higher in two items, or 'Health examination should be made regularly in relation to radiation exposure' and 'Those who work within the area of irradiation should wear protective clothes' and lowest in the item which says 'Radiation exposure dose should be regularly measured for the calibration of the radiation system'. 3. For the behaviors of radiation exposure management, the surveyed students showed highest scores in two items, or 'When irradiating the patient, the radiator should be behind the protective barrier(plate)' and 'It is needed to receive the education of radiation exposure management regularly' While, their score for a behavior described in the item saying 'Before using the radiation system, it is needed to check whether the machine works normally.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.841-847
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• 2021

Related institutions that use radiation are diverse in Korea, such as research, medical care, and education. Recently, the number of examinations and visits to medical institutions is increasing. As a result, the number of radiological examinations in medical institutions is increasing. Radiation safety management is necessary as well as exposure of radiation workers. For safety management, first of all, it is necessary to wear the personal exposure dosimeter correctly and measure it accurately after wearing it. This study tries to evaluate and verify the measurement straightness of PLD devices by radiation of a diagnostic generator. Radiation division irradiation time interval was measured after irradiating 10 times at 10, 30, and 60 sec and irradiating the irradiation distance from 30 to 100 cm at 10 cm intervals to measure the change in absorbed dose depending on the distance. As a result, there was no difference in absorbed dose by time interval. This is considered to be helpful in various studies by using a diagnostic generator for the study of high absorbed dose.

• Progress in Medical Physics
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• v.18 no.4
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• pp.187-193
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• 2007

In an effort to assess the internal absorbed dose of radionuclides that is suitable to Koreans' physiological characteristics, we asked 28 male Koreans to take $^{131}|$ orally, determined the thyroidal uptake and daily urination ratio, and assessed the absorbed dose by organ. As a result, first, 24 hours after administering, the average thyroidal uptake and the daily urination ratio registered 19.70% and 71.12%, respectively. Second, the whole body effective dose according to the thyroidal uptake calculated herein and the existing ICRP-suggested thyroidal uptake of 30% offered 1.464E-08 Sv and 2.189E-08 Sv, respectively, showing a 1.5 times difference. To evaluate the quantity of the absorbed dose of radioactive iodine, we can better reduce the error in assessing the body exposure dose by conducting measurement according to human races rather than depending on the existing ICRP data.

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.85-95
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• 1995

Radiation measuring system using wireless communication method with single channel has been diveloped and tested. In this system, radiation signals from GM tube are transformed into digital pulses in pulse processing circuit and modulated in FSK (frequency shift keying) circuit for digital communication and then wirelessly transmitted to a receiving unit. The digital pulses received are then demodulated in FSK circuit and converted into radiation dose/dose rate in the data acquisition unit to display on the screen of a personal computer. The performance of this system was evaluated by using both a pulse generator and a standard radiation source(Cs-137). In both cases, digital pulses with 5V were observed in pulse processing circuit without distortion of their shape through wireless communication system. The experimental results of radiation measurement by this system after several test-irradiation of GM detector to a standard radiation source(Cs-137), showed good agreement with irradiation dose rate within 10% difference, and proved that this system could be effectively utillized as radiation measuring instrument. It is expected that this wireless radiation measuring system developed for the first time in Korea, can be used as a radiation monitor as well as a personal dosimeter if we can further improve this system to adopt wireless multichannel communication system.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.346-352
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• 2012

Radiation dose estimation on the newborn and infants during radiation examinations, unlike for the adults, is not actively being progressed. Therefore, as an index to present exposure dose during radiation examinations on newborn and infants, entrance skin dose was measured, and the result was compared with results of monte carlo simulation to raise reproducibility of entrance skin dose measurement, and it was proved that various geometry implementation was possible. The resulting values through monte carlo simulation was estimated using normalization factors for entrance skin dose to calibrate radiation dose and then normalized to a unit X ray radiation field size. Average entrance skin dose per one time exposure was $78.41{\mu}Gy$ and the percentage error between measurement by dosimeter and by monte carlo simulation was found to be -4.77%. Entrance skin dose assessment by monte carlo simulation provides possible alternative method in difficult entrance skin dose estimation for the newborn and infants who visit hospital for actual diagnosis.

• Journal of Radiation Protection and Research
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• v.14 no.2
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• pp.23-29
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• 1989

A Lucas cell was established and calibrated by using the double layer tube standard radon source. The calibration factors were 0.031$\pm$0.002 (pCi/l)/(cph/Cell) at room temperature, and 0.029$\pm$0.001 (pCi/l)/(cph/Cell) at $50^{\circ}C$. Radon and its daughters concentrations were measured in a room air for the demonstrating purpose. The concentrations of 222 Rn, $^{218}Po,\;224\;Pb,\;and\;^{214}Bi$ were 0.87, 0.53, 0.35 and 0.26 pCi/l. The total eqilibrium factor was around 0.40 and the WL is $3.33{\times}10^{-3}$, resulting in 30 mrem/yr at this place.