• Journal of Haehwa Medicine
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• v.10 no.2
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• pp.91-96
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• 2002

We arrived at the following conclusions after we have studied esophagitis through the literatures of oriental and western medicine. 1. The western medical causes of acute esophagitis are corrosiveness chemical material, esophageal or gastric disease, trauma, blister stomatitis, filamentous fungus infection and uremia of chronic patient etc, and the oriental medical causes are qi and blood stagnation, blood stasis and stagnation, stagnant phlegm by coldness, heating, dyspepsia and food poisoning etc. 2. The western medical causes of chronic esophagitis are malfunction of lower esophageal sphincter, esophageal tom chink and hernia, increase of gastric pressure by overeating, fatness, pregnancy and ascites etc, and the oriental medical causes are asthenic cardiac qi, hepatic qi attacking stomach by seven kinds of depression, cold-damp stagnation and insufficiency of gastric qi by overeating, excessive drinking and sexual indulgence etc. 3. The main symptoms of acute esophagitis are severe chest pain, instantly vomiting, swallowing pain etc, and chronic esophagitis are occasionally light chest pain, heart bum, anorexia, dysphagia, dizziness, general body weakness etc. These symptoms are come under thoracic obstruction, acid regurgitation, vomiting and chest pain of oriental medicine. 4. The western medical diagnoses of acute and chronic esophagitis have used radiation test, esophageal endoscopy, esophageal pressure test and biopsy etc, and the oriental medical diagnoses have used syndrome differentiation by four examination of inspection, listening and smelling examination, inquiring, pulse-taking and palpitation. 5. The western medical treatments of acute esophagitis have regarded preservation stability of esophagus as a principle, and the oriental medical treatments mainly have used expelling pathogen of expelling cold and regulating qi, cooling and removing stasis, promoting blood circulation to remove blood stasis, eliminating phlegm and regulating qi. 6. The western medical treatments of chronic esophagitis have regarded decrease flowing backward of gastric juice as a purpose, and the oriental medical treatments mainly have used strengthening body resistance of replenishing and strengthening cardioqi, dispersing stagnated hepatoqi, expelling cold and dehygrosis, invigorating stomach and nourishing qi.

• Nuclear Engineering and Technology
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• v.5 no.4
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• pp.291-309
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• 1973

Exposure rates due to leakage gamma-rays from operating reactors TRIGA Mark II and III were measured in a horizontal plane by means of scintillation spectrometry using a 3"$\times$3" cylindrical Nal(T1) detector associated with a 400 channel pulse height analyzer under varied conditions of reactor operation. In determining exposure rate due to the leakage gamma-rays at each point of measurement, Moriuchi's spectrum-exposure rate conversion theory was applied instead of using conventional responce matrix method which necessitates very complicated procedures to convert a spectrum into exposure rate. The results show that a basic pattern of "typical" spectrum of the reactor leakage gamma-rays is neither affected by thermal output of the reactor, nor influenced by overall attenuation in radiation intensity. It was indicated that he attenuation of the leakage gamma-rays in air in terms of exposure rate as a whole follows an exponential law, and the total exposure rate due to the leakage gamma-rays at a certain point is nearly proportional to thermal output of the reactor. The complexity in spectrum measured for a movable core reactor, TRIGA Mark III, was analyzed through spectrum resolution, and proper judgement of the leakage gamma-rays in a complex spectrum was discussed.ctrum was discussed.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3406-3412
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• 2021

A real-time digital time-stamp sorting algorithm used in the In-Beam positron emission tomography (In-Beam PET) is presented. The algorithm is operated in the field programmable gate array (FPGA) and a small amount of registers, MUX and memory cells are used. It is developed for sorting the data of annihilation event from front-end circuits, so as to identify the coincidence events efficiently in a large amount of data. In the In-Beam PET, each annihilation event is detected by the detector array and digitized by the analog to digital converter (ADC) in Data Acquisition Unit (DAQU), with a resolution of 14 bits and sampling rate of 50 MS/s. Test and preliminary operation have been implemented, it can perform a sorting operation under the event count rate up to 1 MHz per channel, and support four channels in total, count rate up to 4 MHz. The performance of this algorithm has been verified by pulse generator and ²²Na radiation source, which can sort the events with chaotic order into chronological order completely. The application of this algorithm provides not only an efficient solution for selection of coincidence events, but also a design of electronic circuit with a small-scale structure.

• Radiation Oncology Journal
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• v.4 no.1
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• pp.15-20
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• 1986

From 1979 to 1984, 39 local allograft irradiations were given to 29 patients: 10 irradiations were administered for prevention and 29 for reversal of acute rejection of transplanted kidney. Three doses of 150 cGy every other day were combined with high-dose of methylprednisolone pulse (1 gm/day) for 3 days. For prevention of acute rejection, local irradiation was delivered on the days 1, 3, and 5 after the transplantation, and for reversal, irradiation started after the diagnosis of acute rejection. Eight out of 10 patients irradiated for prevention had acute allograft rejection, and, what is more, there was no surviving graft at 15 months after transplantation. Reversal of acute rejection was achieved in $71\%$. When the pre-irradiation level of serum creatinine was below $5.5mg\%$, the reversal rate was $93\%$, but above $5.5mg\%$ the reversal rate was only $17\%$ (p<0.01). Reirradiation after failure was not successful. Among 15 reversed patients, $7(47\%)$ had subsequent rejection (s). The functional graft survivals at 6 month, 1, 2, and 3 year were $70\%,\;65\%,\; 54\%,\;and\;54\%$, respectively. Therapeutic irradiation resulted in better graft survival when serum creatinine was below $5.5mg\%$ (p<0.001) or when irradiation started within 15 days after the diagnosis of acute rejection (p<0.001).

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.199-205
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• 2014

In the field of neutron detections, $^3He$ gas, the so-called "the gold standard," is the most widely used material for neutron detections because of its high efficiency in neutron capturing. However, from variable causes since early 2009, $^3He$ is being depleted, which has maintained an upward pressure on its cost. For this reason, the demands for $^3He$ replacements are rising sharply. Research into neutron converting materials, which has not been used well due to a neutron detection efficiency lower than the efficiency of $^3He$, although it can be chosen for use in a neutron detector, has been highlighted again. $^{10}B$, which is one of the $^3He$ replacements, such as $BF_3$, $^6Li$, $^{10}B$, $Gd_2O_2S$, is being researched by various detector development groups owing to a number of advantages such as easy gamma-ray discrimination, non-toxicity, low cost, etc. One of the possible techniques for the detection is an indirect neutron detection method measuring secondary radiation generated by interactions between neutrons and $^{10}B$. Because of the mean free path of alpha particle from interactions that are very short in a solid material, the thickness of $^{10}B$ should be thin. Therefore, to increase the neutron detection efficiency, it is important to make a $^{10}B$ thin film. In this study, we fabricated a $^{10}B$ thin film that is about 60 um in thickness for neutron detection using well-known technology for the manufacturing of a thin electrode for use in lithium ion batteries. In addition, by performing simple physical tests on the conductivity, dispersion, adhesion, and flexibility, we confirmed that the physical characteristics of the fabricated $^{10}B$ thin film are good. Using the fabricated $^{10}B$ thin film, we made a proportional counter for neutron monitoring and measured the neutron pulse height spectrum at a neutron facility at KAERI. Furthermore, we calculated using the Monte Carlo simulation the change of neutron detection efficiency according to the number of thin film layers. In conclusion, we suggest a fabrication method of a $^{10}B$ thin film using the technology used in making a thin electrode of lithium ion batteries and made the $^{10}B$ thin film for neutron detection using suggested method.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.253-259
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• 2014

Large volume of $6{\times}6{\times}12mm^3$ CdZnTe ${\gamma}$-ray detector was fabricated with CdZnTe single crystals grown by Traveling Heater Method (THM) to evaluate the energy resolution of 662 keV in $^{137}Cs$. Hole tailing effect which originated from the large mobility difference in electron and hole degrade energy resolution of radiation detector and its effects become more severe for a large volume detectors. Generally, single carrier collection technique is very useful method to remove/minimize hole tailing effect and thereby improvement in energy resolution. Virtual Frisch-grid technique is also one of single charge collection method through weighting potential engineering and it is very simple and easily applicable one. In this paper, we characterized CZT detector grown by THM and evaluated the effectiveness of virtual Frisch-grid technique for a high energy gamma-ray detector. The proper position and width of virtual Frisch-grid was determined from electric field simulation using ANSYS Maxwell ver. 14.0. Energy resolution of 2.2% was achieved for the 662 keV ${\gamma}$-peak of $^{137}Cs$ with virtual Frisch-grid CdZnTe detector.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1185-1192
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• 2008

In this paper, a wideband LC oscillator which is composed of a high voltage switch and a fat dipole antenna was designed and radiation characteristics are analyzed. A Marx generator was used as a high voltage pulse generator of the proposed wideband LC oscillator and $90^{\circ}$ corner reflector was used to obtain high directivity. According to simulated and measured results, 3 dB bandwidth of high voltage switch without fat dipole based on the received power is about 9%(${\lambda}_1=0.7\;m$) and bandwidth Is about 30%(${\lambda}_2=1\;m$) by using the LC oscillator containing high voltage switch and fat dipole. Consequently, fat dipole affects not only radiating power but also operating frequency and bandwidth of the LC oscillator. This study will be useful to determine operating frequency and radiating power when we design LC oscillator which uses a high voltage switch and a fat dipole.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.475-480
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• 2018

In lower abdominal MRI scan, patients have been tested by physically contacting with the body array coil. In this study, we have designed the acrylic assistant equipment (ACR) which allows the contactless scan of the patient to the coil and evaluated the feasibility by comparing the acquired images with ACR to those obtained without ACR. We tested 10 cases (F: 5, m: 5) by using the Ingenia $3.0T^{TM}$ MR system and dStreamTM torso coil (Philips Healthcare, Netherlands). We implemented T1 AX TSE and eTHRIVE (GRE) techniques. The scanned images were quantitatively and qualitatively assessed. In qualitatively, the TSE shows 4.44 and 4.56 mean values with and without the ACR and 4.34 and 4.28 at the GRE, respectively. In quantitatively, the TSE shows 12.15 CNR, 17.95 SNR and 12.71 CNR, 18.96 SNR with and without the ACR. And GRE shows 17.72 CNR, 22.59 SNR and 18.26 CNR, 24.47 SNR with and without the ACR, respectively. We have designed and implemented the acrylic assistant equipment to lower abdominal patients. Our data indicate that it is possible to obtain similar image qualities to current lower abdominal MRI scan without the physical contact to the patient.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.5
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• pp.556-563
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• 2007

We carried out a laboratory scale experiment about the characteristics of chemically active species produced in hybrid gas-liquid discharges. The electrode configuration which had high voltage electrode in the gas phase and ground electrode in the liquid was utilized while high voltage electrode has been typically positioned in the liquid in other studies. Our electrode was configured in such a way as to increase the energy efficiency of chemical reactions by creating a higher electrical field strength and a narrower pulse width than the typical electrode configuration. The highest ozone concentration was obtained at 45 kV which was the medium value in operating voltages. The decrease of solution conductivity increased the resistance of liquid phase and the electric field strength through the gas phase, so ozone gene-ration rate was enhanced. The increase of voltage promoted the production rate of hydrogen peroxide by increasing the electric field strength. In a lower voltage, the increase of solution conductivity increased the degradation rate of $H_2O_2$, so the $H_2O_2$ generation rate decreased. On the other hand, the effects of UV radiation, shock waves etc. increased the $H_2O_2$ generation rate as the solution conductivity increased. A higher rate of $H_2O_2$ generation can be achieved by mixing argon to oxygen which generates a stronger and more stable discharges.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.299-306
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• 2009

Purpose : To compare radiation dose for coronary CT angiography (CTA) obtained with 6 examination protocols such as a retrospectively ECG gated helical scan, a prospectively ECG gated sequential scan, low kVp technique, and cardiac dose modulation technique. Materials and Methods : Coronary CTA was performed by using 6 current clinical protocols to evaluate effective dose and organ dose in primary beam area with anthropomorphic female phantom and glass dosimetric system in 64 channel multi-detector CT. After acquiring topograms of frontal and lateral projection with 80 kVp and 10 mA, main coronary scan was done with 0.35 sec tube rotation time, 40 mm collimation ($0.625\;mm{\times}64\;ea$), small scan field of view (32 cm diameter), 105 mm scan length. Heart beat rate of phantom was maintained 60 bpm in ECG gating. In constant mAs technique 120 kVp, 600 mA was used, and 100 kVp for low kVp technique. In a retrospectively ECG gated helical CT technique 0.22 pitch was used, peak mA (600 mA) was adopted in range of $40{\sim}80%$ of R-R interval and 120mA(80% reduction) in others with cardiac dose modulation. And 210 mAs was used without cardiac dose modulation. In a prospectively ECG gated sequential CT technique data were acquired at 75% R-R interval (middle diastolic phase in cardiac cycle), and 120 msec additional padding of the tube-on time was used. For effective dose calculation region specific conversion factor of dose length product in thorax was used, which was recommended by EUR 16262. Results : The mean effective dose for conventional coronary CTA without cardiac dose modulation in a retrospectively ECG gated helical scan was 17.8 mSv, and mean organ dose of heart was 103.8 mGy. With low kVp and cardiac dose modulation the mean effective dose showed 54.5% reduction, and heart dose showed 52.3% reduction, compared with that of conventional coronary CTA. And at the sequential scan(SnapShot pulse mode) under prospective ECG gating the mean effective dose was 4.9 mSv, this represents an 72.5% reduction compared with that of conventional coronary CTA. And heart dose was 33.8 mGy, this represents 67.4% reduction. In the sequential scan technique under prospective ECG gating with low kVp the mean effective dose was 3.0 mSv, this represents an 83.2% reduction compared with that of conventional coronary CTA. And heart dose was 17.7 mGy, this represents an 82.9% reduction. Conclusion : In coronary CTA at retrospectively ECG gated helical scan, cardiac dose modulation technique using low kVp reduced dose to 50% above compared with the conventional helical scan. And the prospectively ECG gated sequential scan offers substantially reduced dose compared with the traditional retrospectively ECG gated helical scan.