• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.37-42
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• 2017

We measured the absorbed dose and the area dose using an ionization chamber type of area dose product (DAP) meter and measured the calibration factor in the X-ray examination. In the indirect dose measurement method, the detector was installed in the radiation part of the X-ray equipment, and the measured value was calculated as the dose at the exposure part. The instrument used to calculate the calibration factor was an X-ray equipment (DK-550R / F, DongKang Medical Co., Ltd., Seoul, Korea). The calibration method for the calibration factor was to connect the DAP meter (PD-8100, Toreck Co. Ltd., Japan) to the calibration dosimeter tube voltage of 70 kV, tube current of 500 mA, 0.158 sec. The reference dosimeter used a semiconductor (DOSIMAX plus A, Scanditronix, $Wellh{\ddot{o}}fer$, Germany). After installing the DAP meter on the front of the multi-collimator of the ionization chamber, the calibration factor of the dosimeter was obtained using the reference dosimeter for accurate dose measurement. Experimental exposure values and values from the calibration dosimeter were calculated by multiplying each calibration factor. The calibration factor was calculated as 1.045. In order to calculate the calibration coefficient according to the tube voltage in the ionization type DAP dosimeter, the absorbed dose and the area dose were calculated and the calibration factor was calculated. The corrective area dose was calculated by calculating the calibration factor of the DAP meter.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.825-833
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• 2022

In 3D printing technology, materials that can be printed are increasing along with the development of material engineering, and materials that can be used in the field of radiation are also increasing. Therefore, depending on the composition and density of the materials used, the applied field can be different and applied, so the composition and characteristics of the materials must also be considered. In this study, 10 filaments with different properties were selected using a 3D printer of the FDM (Fused Deposition Modeling) method, and the brightness change of each filament was checked using a diagnostic X-ray generator, and the CT number was measured through CT. I wanted to find a material similar to bone. As a result, a material called silicon carbide was found, which has a similar brightness and CT number to bone. It is thought that further research will be presented as basic data for various studies with a density similar to that of human bones.

• Journal of the Korean Society of Radiology
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• v.6 no.4
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• pp.313-320
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• 2012

Current medical institutions with the development of medical technology to the increased demand for health use of radiation equipment is increasing rapidly. Direct radiation from the patient receives the aim of reducing exposure as much as possible is important and the spatial dose of scattered radiation with in the space to engage in reducing healthcare physician, radiation workers and carers need to reduce indirect exposure. X-ray radiation workers and caregivers in the X-ray room to wearing of protective clothing is advised. However Radiation worker sand caregivers of patients with secondary is done, by wearing protective clothing to wear protective clothing because of the weight and discomfort have been neglected. In this study, based on the presence or absence of clothing scattered radiation from space to measure distances, depending on the horizontal and height by measuring the angle of the importance of wearing protective clothing were investigated.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.245-249
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• 2013

Neutron sources from photonuclear reaction with 46-MeV electron linear accelerator at Research Reactor Institute, Kyoto University used for resonance energy measurement of natural tantalum. BGO($Bi_4Ge_3O_{12}$) scintillation detectors used for measurement of the prompt gamma ray from the natural tantalum sample. The BGO spectrometer was composed geometrically as total energy absorption detector. The electric signal from the spectrometer was analyzed for TOF(Time-of-Flight) spectrum which is used identification of neutron capture resonance energy. In this study, the neutron energy region is from 1 to 200 eV, because of strong X-ray effect produced photonuclear reaction in Ta target, the measurement was performed to below 1 keV energy region. The resonance energy was compared with the evaluated values(ENDF/B-VI, Mughabghab). All of the resonances from 4.28 ~ 200 eV were seen in the present measurement except 144.3 eV resonance.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.50-51
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• 2003

강한 세기의 레이저가 원자에 입사하먼 원자내의 쿨룽 퍼텐셜이 심하게 왜곡되어 전자가 터널링 이온화된다. 이 이온화된 전자가 레이저 장에 의해 가속되었다가 레이저 장의 방향이 바뀌면 원래의 원자와 결합하면서 고에너지의 광자를 발생시킨다. 레이저의 주기적인 상호작용에 의해 생성된 광자의 에너지는 입사하는 레이저 에너지의 홀수 배에 해당하게 되며, 이를 고차조화파(high-order harmonics)라 한다. 특히 고차조화파는 연엑스선 영역의 빛을 작은 규모의 장치와 적은 비용으로도 발생시키기 때문에 연엑스선의 광원으로서 각광을 받고 있으며, 여러 분야에 사용되어지기 위한 연구가 폭넓게 이루어지고 있다. (중략)

• Radiation Oncology Journal
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• v.4 no.2
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• pp.115-128
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• 1986

Hyperthermia can enhance the radiation effect as a synergistic reaction in combined X-ray irradiation and hyperthermia; hyperthermia sensitize radioresistant S-phase cells and inhibit cellular recovery from sublethal damage. We fabricated 100 watts, 2450 MHz microwave applicator for hyperthermia and planned the method and condition of heating and measured the temperature by using Agar phantom as a preliminary test. For biological examination, 102 rats were divided into 4 groups as hyperthermia, X-ray irradiation (6Gy-15Gy), combined X-ray and hyperthermia, and normal control groups. Microscopic examination of the rectum and bladder was done and the results were as followings: 1. The microwave generator with 100 watts, 2450MHz magnetron could be heating up to $40^{\circ}{\sim}50^{\circ}C$ for one hour in living tissue. 2. The thermal distribution in tissue equivalent phantom with microwave can be maintained at $40^{\circ}{\sim}44^{\circ}C$ in area of 3cm in depth and 2-10cm in diameter. 3. In Hyperthermia alone group, there was submucosal edema of the rectum but no histologic change in the urinary bladder was seen. 4. The minimal necrosis of the mucosa was appeared in the rectum and bladder after 15 days of 6 Gy and 8 Gy irradiation respectively. The minimal necrosis of the muscle layer of rectum and bladder was appeared after 15 days of 8Gy and 60days of 10Gy irradiation respectively. 5. In combined group of radiation and hyperthermia, thermal enhancement ratio (calculated at necrosis of mucosa and muscle layer) of rectum and bladder was 1.0, and it suggest that there is no change of tolerance dose of normal rectum and bladder.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.176-181
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• 2011

$Y_{1-x}BO_3:Ce_x^{3+}$ ceramic phosphors were synthesized with changing the concentration of $Ce^{3+}$ ion by using a solid-state reaction method. The crystal structure, surface morphology, and optical properties of the blue phosphors were investigated by using X-ray diffractometer (XRD), scanning electron microscopy, and photoluminescence and photoluminescence excitation spectrophotometry, respectively. The XRD results showed that the main peak of the phosphor powders occurs at (401)와 ($31\bar{2}$) planes. As for the optical properties, the excitation spectrum occurred at 243 nm and the value of blue emission intensity peaking at 469 nm reached the maximum when the concentration of $Ce^{3+}$ ion was 0.10 mol.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.147-154
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• 2020

In this study, four types of composite added filtration (aluminum, nickel, copper, and zinc) were combined for each thickness to evaluate dose reduction and optimal images due to X-ray attenuation. To evaluate dose and image quality. X-ray generators, Dose Area Product(DAP) and ICY programs with RQR9 standard quality were used. In the image quality evaluation element (PSNR, RMSE, SSIM), only images with PSNR value of 30 dB or more were analyzed. As a result, the best combination in dose evaluation was 3 mmAl + 0.6 mmNi (0.16µGy㎡), and the best filter in image quality evaluation was 0.9 mmAl (PSNR 34.24dB, RMSE 79.52, SSIM 0.24). In this study, the dose aspect and the image quality aspect are mentioned, So it is considered that further studies on patient's exposure dose and optimal image will be needed in the future.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.215-222
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• 2016

X-ray mammography is the most effective method for the diagnosis of calcified lesions of various breast diseases. To reduce patient dose and to obtain optimal image required for diagnosis, the performance of the mammography system should be maintained continuously. Because the target (anode) angle of the X-ray tube is measured from the central X-ray, the effective angle can be slightly different in view of the position on the detector, which can result in degrading spatial resolution of the imaging within the field of view. In this study, we measured the MTF to examine spatial resolution for positions on the detector in the digital mammography system. For a tungsten wire of $50{\mu}m$ diameter, the highest spatial frequency was obtained. It meant that a wire diameter for measuring MTF through LSF should be small compared to the pixel size of the detector used in the mammography system. The spatial resolution showed slightly different performance according to positions on the detector. The center position gave the best spatial resolution and positions away from the center showed the degraded performance although the difference of the spatial resolution was small. The effective focal spot size of the full width at half maximum also showed similar result. It concluded that the slightly increase of the effective focal spot size gave the degradation of the spatial resolution for positions on the detector.

• Journal of radiological science and technology
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• v.26 no.2
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• pp.37-42
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• 2003

Purpose : Computed tomographic equipment is essential for diagnosis by means of radiation. With passage of time and development of science computed tomographic was developed time and again and in future examination by means of this equipment is expected to increase. In this connection these authors measured rate of scatter ray generation at front of lead glass for patients within control room of computed tomographic equipment room and outside of entrance door for exit and entrance of patients and attempted to ind out method for minimizing exposure to scatter ray. Material and Method : From November 2001 twenty five units of computed tomographic equipments which were already installed and operation by 13 general hospitals and university hospitals in Seoul were subjected to this study. As condition of photographing those recommended by manufacturer for measuring exposure to sauter ray was use. At the time objects used DALI CT Radiation Dose Test Phantom fot Head (${\oint}16\;cm$ Plexglas) and Phantom for Stomache(${\oint}32\;cm$ Plexglas) were used. For measurement of scatter ray Reader (Radiation Monitor Controller Model 2026) and G-M Survey were used to Survey Meter of Radical Corporation, model $20{\times}5-1800$, Electrometer/Ion Chamber, S/N 21740. Spots for measurement of scatter ray included front of lead glass for patients within control room of computed tomographic equipment room which is place where most of work by gradiographic personnel are carried out and is outside of entrance door for exit and entrance of patients and their guardians and at spot 100 cm off from isocenter at the time of scanning the object. The results : Work environment within computed tomography room which was installed and under operation by each hospital showed considerable difference depending on circumstances of pertinent hospitals and status of scatter ray was as follows. 1) From isocenter of computed tomographic equipment to lead glass for patients within control room average distance was 377 cm. At that time scatter ray showed diverse distribution from spot where no presence was detected to spot where about 100 mR/week was detected. But it met requirement of weekly tolerance $2.58{\times}10^{-5}\;C/kg$(100 mR/week). 2) From isocenter of computed tomographic equipment to outside of entrance door where patients and their guardians exit and enter was 439 cm in average, At that time scatter ray showed diverse distribution from spot where almost no presence was detected to spot with different level but in most of cases it satisfied requirement of weekly tolerance of $2.58{\times}10^{-6}\;C/kg$(100 mR/week). 3) At the time of scanning object amount of scatter ray at spot with 100 cm distance from isocenter showed considerable difference depending on equipments. Conclusion : Use of computed tomographic equipment as one for generation of radiation for diagnosis is increasing daily. Compared to other general X-ray photographing field of diagnosis is very high but there is a high possibility of exposure to radiation and scatter ray. To be free from scatter ray at computed tomographic equipment room even by slight degree it is essential to secure sufficient space and more effort should be exerted for development of variety of skills to enable maximum photographic image at minimum cost.