• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.864-870
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• 2014

To propose a basis for the selection of personal dosimeters to measure radiation dose administration of radiation workers as a way to evaluate the usefulness dosimeter. For the dosimetry of the radiation workers 2012, during 1 year, 30 were radiation workers to measure personal dose. By personal exposure is measured cumulative dose, is investigated the performance of the TLD, PLD, OSLD. And comparing the measured value of each dosimeter dose and analyzed. Medical institutions, inspection work and quarterly confirmed the cumulative exposure dose of radiation workers. Using DAP and Ion-Chamber, to measure to compare TLD, PLD, OSLD dosimeter performance. A comparison of the directly through the X-ray dosimeter and The absolute value of the Ion-Chamber, OSLD more similar than in the TLD and PLD showed the dose values so the excellent ability to measure the results. Also in radiation generating area dose of radiation workers is higher than that in OSLD. Consequently, in terms of the individual exposure management OSLD is appropriated and beneficial than others.

• Journal of radiological science and technology
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• v.41 no.2
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• pp.129-134
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• 2018

The present study made a phantom for gamma ray of 140 keV radiated from $^{99m}Tc$, examined shielding effect of lead by thickness of the shielding material, and measured surface dose and depth dose by body depth. The OSL Nano Dot dosimeter was inserted at 0, 3, 15, 40, 90, and 180 mm depths of the phantom, and when there was no shield, 0.2 mm lead shield, 0.5 mm lead shield, The depth dose was measured. Experimental results show that the total cumulative dose of dosimeters with depth is highest at 366.24 uSv without shield and lowest at 94.12 uSv with 0.5 mm lead shield. The shielding effect of 0.2 mm lead shielding was about 30.18% and the shielding effect of 0.5 mm lead shielding was 74.30%, when the total sum of the accumulated doses of radiation dosimeter was 100%. The phantom depth and depth dose measurements showed the highest values at 0 mm depth for all three experiments and the dose decreases as the depth increases. This study proved that the thicker a shielding material, the highest its shielding effect is against gamma ray of 140 keV. However, it was known that shielding material can't completely shield a body from gamma ray; it reached deep part of a human body. Aside from the International Commission on Radiation Units and Measurements (ICRU) recommending depth dose by 10 mm in thickness, a plan is necessary for employees working in department of nuclear medicine where they deal with gamma ray, which is highly penetrable, to measure depth dose by body depth, which can help them manage exposed dose properly.

• Progress in Medical Physics
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• v.2 no.2
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• pp.129-139
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• 1991

The method of etching tracks in PN-3 dosimeter has been applied to tracks of recoil protons from a neutron source. Both the etch and the detection response of PN-3 has been studied as a function of etched-track diameters against various parameters. We could obtain very useful informations about charge, energy, and mass of particles and the relationship between the track etching rate and the track forming procedure in order to analyze the particle recorded in the solid state track detector. The best etching condition could be found by means of changing the etching circumstances for various energies and particles in order to detect the charged particle accurately. It could be influenced widely that the polymer plastic detector could develep the detecting technique for the low energy level neutron and could be used as a neutron dosimeter in the radiation field such as the nuclear power station, the medical institute and the nondtructive testing institute.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.6.1-6.6
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• 2014

Objectives Hospitalized patients are vulnerable to sleep disturbances because of environmental stresses including noise. While most previous studies on hospital noise and sleep have been performed for medical machines in intensive care units, there is a limited data for patients hospitalized in medical wardrooms. The purpose of present study was to measure noise level of medical wardrooms, identify patient-perceived sources of noise, and to examine the association between noise levels and sleep disturbances in hospitalized patients. Methods Noise dosimeters were used to measure noise level in 29 inpatient wardrooms at a university hospital. Sleep pattern and disturbance were assessed in 103 hospitalized patients, using the Pittsburgh Sleep Quality Index (PSQI) and Leeds Sleep Evaluation Questionnaire. Results The mean equivalent continuous noise level for 24 hours was 63.5 decibel A (dBA), which was far higher than 30 dBA recommended by the World Health Organization for hospital wardrooms. Other patients sharing a room were perceived as the most common source of noise by the patients, which was usually preventable. Of the patients in the study, 86% had bad sleep as assessed by the PSQI. The sleep disturbance was significantly correlated with increasing noise levels in a dose response manner. Conclusions Systemic organizational interventions are needed to keep wardrooms private and quiet to reduce sleep disturbance.

• The Journal of Korean Society for Radiation Therapy
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• v.1 no.1
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• pp.63-69
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• 1985

High energy electron beams took effect for tumor radio-therapy, however, had a lot of problems in clinical application because of various conversion factors and complication of physical reactions. Therefore, we had experimentally studied the important properties of high energy electron beams from the linear accelerator, LMR-13, installed in Yonsei Cancer Center. The results of experimental studies on the problems in the 8, 10, 12 Mev electron beam therapy were reported as following. 1. On the measurements of the outputs and absorbed does, the ionization type dosimeters that had calibrated by $^{90}Sr$ standard source were suitable as under $3\%$ errors for high energy electrons to measure, but measuring doses in small field sizes and the regions of rapid fall off dose with ionization chambers were difficult. 2. The electron energy were measured precisely with energy spectrometer consisted of magnet analyzer and tele-control detector and the practical electron energy was calculated under $5\%$ errors by maximum range of high energy electron beam in the water. 3. The correcting factors of perturbated dose distributions owing to radiation field, energy and material of the treatment cone were checked and described systematically and variation of dose distributions due to inhomogeneous tissues and sloping skin surfaces were completely compensated. 4. The electron beams, using the scatters; i.e., gold, tin, copper, lead, aluminium foils, were adequately diffused and minimizing the bremsstrahlung X-ray induced by the electron energy, irradiation field size and material of scatterers, respectively. 5. Inproving of the dose distribution from the methods of pendulum, slit, grid and focusing irradiations, the therapeutic capacity with limited electron energy could be extended.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.315-333
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• 1990

This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography (l4 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator(60㎜ in diameter, 20㎝ in length) and rectangular collimator(35㎜ × 44㎜, 40㎝ in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rates of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling techniuqe, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

• Imaging Science in Dentistry
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• v.40 no.1
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• pp.15-23
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• 2010

Purpose : This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. Materials and Methods : 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Results : Effective doses in ${\mu}Sv$ ($E_{2007}$) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. Conclusion : From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

• Progress in Medical Physics
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• v.2 no.1
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• pp.17-28
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• 1991

Generally, it is an accurate radiation measurement technique for processors fo thermoluminescent dosimenters(TLDs) to characterize each element they use by producing element correction factors(FCFs). TLDs are classified into three groups such as reference. control, and field TLDs. Reference TLDs are used only for the production of ECFs for the control and field TLDs. They are kept locked in a safe place except when it is necessary to use a subset of them to produce ECFs for the control and field TLDs. The ECF of a given element is a measure of the response of the element relative to the mean response of an arbitrarily selected group of reference elements. As TLDs are used in the field, their relative responses to radiation might be decreased due to muliple readings and physical abuse. Therefore, the producditon of ECFs are performed initially and periodically during the field use. This element correction method provides an excellent tool to examine new TLDs and to monitor the reliability of old TLDs. This paper discuss the 10 step procedures developed to produce and examine ECFs.

• Journal of Environmental Health Sciences
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• v.37 no.2
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• pp.94-101
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• 2011

Objectives: The purpose of this study is to evaluate the noise exposures of firefighters according to their time-dependent activity patterns. Methods: Personal exposure levels were measured for six days and nights using noise dosimeters; three days and nights for on-duty tasks, the other days and nights for off-duty activities. Results: The total amount of time spent in the workplace was 13,677 min (67%), outside areas 4,833 min (23%), in transit 1,002 min (5%), and other indoor area 807 min (4%) during a working period. However, during off-days they spent 10,858 min (76%) at home, 1,382 min (10%) outdoors, 1,225 min (9%) other indoors, and 493 min (3%) in transit. As a result of individual exposure levels, TWA did not exceed 90 dBA of the occupational exposure limit for the majority of the firefighters, whereas the levels of Lmax were 119 dBA, which were higher than the noise levels of firefighters in USA. Sometimes during dispatching the levels of Lpeak exceeded the ACGIH exposure standard (140 dBC). The Leq levels in transit were higher than the levels in home and other indoors even though the activity time is short. Conclusions: This paper characterized the noise exposure patterns of firefighters in Korea. We suggest that special noise sources, including sirens and speaker phones, should be readjusted to reduce noise exposure.

• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.189-198
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• 1994

An angular dependence experiment was made and a performance test of the Teledyne dosimetry system was done in accordance with the ANSI N13.11-1992. The angular dependence experiment was performed with $^{137}Cs$ and low energy X-ray beam. Teledyne dosimetry system performed well at the $0^{\circ}$ angle of incidence for all dosimeters in both vertical and horizontal irradiations. It would have easily passed the 0.5 tolerance limit. But the dosimetry system was not performed well at the ${\pm}60^{\circ}$ angle of incidence for low energy X-ray beam. The accuracy for $^{137}Cs$ beam at all angles of incidence was within the 0.5 tolerance limit. Therefore performance of the dosimetry system could be considered acceptable in case that the dosimeter is irradiated to $^{137}Cs$ beam. However, it could not be acceptable for the dosimeter irradiated to low energy X-ray, especially at more than ${\pm}40^{\circ}$