• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.4
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• pp.16-22
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• 2010

In this paper, we evaluated the effect with respect to the light of 700-1,100 nm NIR(near infrared radiation) for spectrophotometer. Standard, red, yellow, green and blue color paper which was Munsell color paper were used for experiments. Our used light is incandescent lamp, fluorescent lamp, invert fluorescent lamp and combined lamp. Each color paper was measured 20 times. Therefore we concluded that it is possible to build a spectrophotometer for NIR(near infrared radiation) measurement we applied an spectrophotometer to measurement system in incandescent lamp.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.531-531
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• 2007

현재 널리 사용되고 있는 X선 영상 검출기의 문제점을 해결하기 위해 새로운 연구가 활발히 진행되고 있다. 본 논문에서는 새로운 X선 검출기로써의 가능성 제시를 위해 Display용 PDP(Plasma Display panel)를 디지털 X-ray Detector로 적용하기 위한 기본적인 X-ray에 대한 반응성을 검증하였다. PDP의 X-ray Detector로의 사용 가능성을 보기 위하여, 실험에 사용된 panel은 상용화된(commercial) Display용 PDP의 기본적인 구조와 똑같은 구조의 sample을 제작하여 사용하였다. 제작된 panel은 상판에 Substrate glass와 유전체층, 투명전극을 형성하고, 버스 전극층과 MgO층을 형성하였다. 하판에는 격벽을 제작하고 형광체(R.G.B)층을 형성하고, 어드레스 전극을 형성하여 기존의 Display용 PDP와 똑같은 구조를 지니게 하였다. 이렇게 제작된 panel의 X-선 검출기로서의 전기적 특성물 조사하기 위해 누설전류(Dark current), X선 민감도(X-ray sensitivity), 그리고 선형특성(Linearity)을 측정하였다. 측정 결과, 누설전류가 낮고 X-선 검출기로서의 가능성이 충분한 민감도를 보이며, 선형적 특성 또한 우수한 결과를 보이는 등 안정된 전기적 동작특성을 보였다. 이러한 결과로부터 기존에 사용되어오던 디스플레이용 PDP의 구조적 변경을 통하여 상용화된 PDP룰 디지털 X-선 검출기로서의 적용 가능성을 확인할 수 있었다.

• Journal of Biomedical Engineering Research
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• v.42 no.3
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• pp.116-124
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• 2021

It is important to differentiate between the target tissue (or organ) and the rest of the tissue before incision during surgery. And when it is necessary to preserve the differentiated tissues, the blood vessels connected to the tissue must be preserved together. Various non-invasive medical imaging methods have been developed for this purpose. We aimed to develop a medical imaging system that can simultaneously apply fluorescence imaging using indocyanine green (ICG) and laser speckle contrast imaging (LSCI) using laser speckle patterns. We designed to collect images directed to the two cameras on a co-axial optical path and to compensate equal optical path length for two optical designs. The light source used for fluorescence and LSCI the same 785 nm wavelength. This system outputs real-time images and is designed to intuitively distinguish target tissues or blood vessels. This system outputs LSCI images up to 37 fps through parallel processing. Fluorescence for ICG and blood flow in animal models were observed throughout the experiment.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.25-29
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• 2004

Among the digital radiography systems, the computed radiography Image Plate Detector System is most frequently being used for the general radiography and also this system commonly diffracts the x-ray images since it is the system that is influenced by the light diffusion from the fluorescent substances. In this study, by using the X-ray Generator, a comparative analysis has been made between 2 different models of computer radiography image plate investigate each model's resolution and sharpness through the modulation transfer function(MTF) measurement. For the analysis, two image plates for general radiography one Fuji ST-VN model(more than 3years old) and one Fuji ST-VL model(less than 2years old) that are currently being used in "Hospital A" were sampled for the MTF measurement here. As the experimental method for this study, the resolution chart method has been carried out by using X-ray generator. Also all the experimental data were printed out by laser printer and measured by microdensitometer. As the results of the experiment carried out in this study, some differences have been found between the two different IP models and Fuji ST-VL has shown its excellence in both of the resolution and the sharpness fields.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.1
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• pp.17-23
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• 2008

Purpose: Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. but imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Materials and Methods: Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in seperately H&N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. Results: The results of the measured skin dose are described in here. The skin dose of Head & Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Conclusion: Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low mAs technique.

• Radiation Oncology Journal
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• v.27 no.1
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• pp.42-48
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• 2009

Purpose: The introduction of image guided radiation therapy/four-dimensional radiation therapy (IGRT/4DRT) potentially increases the accumulated dose to patients from imaging and verification processes as compared to conventional practice. It is therefore essential to investigate the level of the imaging dose to patients when IGRT/4DRT devices are installed. The imaging dose level was monitored and was compared with the use of pre-IGRT practice. Materials and Methods: A four-dimensional CT (4DCT) unit (GE, Ultra Light Speed 16), a simulator (Varian Acuity) and Varian IX unit with an on-board imager (OBI) and cone beam CT (CBCT) were installed. The surface doses to a RANDO phantom (The Phantom Laboratory, Salem, NY USA) were measured with the newly installed devices and with pre-existing devices including a single slice CT scanner (GE, Light Speed), a simulator (Varian Ximatron) and L-gram linear accelerator (Varian, 2100C Linac). The surface doses were measured using thermo luminescent dosimeters (TLDs) at eight sites-the brain, eye, thyroid, chest, abdomen, ovary, prostate and pelvis. Results: Compared to imaging with the use of single slice non-gated CT, the use of 4DCT imaging increased the dose to the chest and abdomen approximately ten-fold ($1.74{\pm}0.34$ cGy versus $23.23{\pm}3.67$cGy). Imaging doses with the use of the Acuity simulator were smaller than doses with the use of the Ximatron simulator, which were $0.91{\pm}0.89$ cGy versus $6.77{\pm}3.56$ cGy, respectively. The dose with the use of the electronic portal imaging device (EPID; Varian IX unit) was approximately 50% of the dose with the use of the L-gram linear accelerator ($1.83{\pm}0.36$ cGy versus $3.80{\pm}1.67$ cGy). The dose from the OBI for fluoroscopy and low-dose mode CBCT were $0.97{\pm}0.34$ cGy and $2.3{\pm}0.67$ cGy, respectively. Conclusion: The use of 4DCT is the major source of an increase of the radiation (imaging) dose to patients. OBI and CBCT doses were small, but the accumulated dose associated with everyday verification need to be considered.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.422.2-422.2
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• 2014

가스장 이온원(GFIS: Gas Field Ionization Source)은 전자현미경보다 분해능이 향상된 이온현미경의 광원으로 사용하기 위하여 연구되고 있고, 큰 각전류 밀도, 작은 크기의 가상 이온원 그리고 좁은 에너지 퍼짐을 특징으로 한다. 여러 가지 장점을 가지고 있는 GFIS을 개발하기 위해서는 GFIS에서 발생된 이온빔의 형상을 관찰 것이 매우 중요하며, 이러한 관찰을 위한 시스템에는 주로 마이크로 채널 플레이트 (MCP: Micro Channel Plate)가 사용된다. MCP는 채널내부에 입사한 입자의 에너지에 의해서 생성된 이차전자를 수 천 배에서 수 백 만 배 이상 증폭시켜 형광판에 조사하고 발광시키는 방법으로 작은 신호를 영상으로 관찰 할 수 있도록 한다. MCP의 큰 증폭비는 작은 크기의 신호를 큰 신호로 증폭하여 관찰하는데 용이하여, GFIS 방법으로 생성된 이온빔(이온빔 전류 값은 pA 수준)을 관찰하기에 적합하다. 그러나 MCP를 이용하여도 증폭된 이온빔의 세기가 매우 작기때문에 생성된 이온빔 형상을 정확하게 관찰하기 위해서는 MCP의 형광판을 촬영하는 카메라 노출시간을 길게하여 데이터 수집 시간을 늘려야 하는 문제가 있다. 본 발표에서는 이온빔 형상 관찰에 소요되는 시간을 단축하기 위하여 MCP의 잡음이 GFIS의 이온빔 이미지 관찰에 미치는 영향을 분석하고 이를 제거 방법을 소개한다. 본 연구에서는 GFIS 방출 이온빔의 이미지에 포함된 MCP 잡음 특성을 장(전계)이온현미경 (Field Ion Microscope)실험을 통하여 분석하였고, 디지털 이미지 처리 방법을 이용하여 방출 이온빔 이미지에서 MCP 잡음을 제거하여 방출 이온빔 이미지만 추출할 수 있었다. 본 연구에서 제안한 방법을 GFIS 방출 이온빔 관찰시스템에 적용함으로써 기존 방법에 비해 노출시간을 단축하여 방출 이온빔을 관찰 할 수 있었으며, 노이즈 제거 효과로 향상된 이온빔 형상을 얻을 수 있었다. 본 연구결과의 관찰시간 단축과 향상된 이온빔 형상 획득은 이온현미경 개발에 필수적인 단원자 이온빔을 보다 효율적으로 개발할 수 있으며 디지털 이미지 처리로 GFIS 이온빔 생성을 자동화하는데 응용할 수 있다. 더불어 기존방법에 비해 이미지 획득을 위한 MCP의 노출시간을 단축할 수 있으므로 실험장비 수명 단축 방지 및 관리에 큰 장점이 있다.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.767-773
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• 1990

The effect of storage conditions on the oxidative stability of cholesterol in butter was studied by quantifying cholesterol oxides by GC-MS. Experimental variables for storage conditions were packaging, storage temperature, light source, and storage period. No cholesterol oxides were detected from packaged butter under all storage conditions. When unpackaged butter was stored under ultraviolet light at ambient temperature, $7{\alpha}-hydroxycholesterol,\;7{\beta}-hydroxycholesterol$, cholesterol ${\beta}-epoxide$, cholesterol ${\alpha}-epoxide$, cholestane-triol were detected after 2, 4, 6 and 8 weeks of storage. The amounts of cholesterol oxide species produced were different depending on the storage periods. The amounts of each cholesterol oxides, $7{\alpha}-hydroxycholesterol,\;7{\beta}-hydroxycholesterol$, cholesterol ${\beta}-epoxide$, cholesterol ${\alpha}-epoxide$, and cholestane-triol, produced after 2 weeks of storage were 34.2, 14.0, 12.1, 1.30, and 0.50 ppm, respectively, and after 8 weeks of storage were 68.1, 29.1, 56,3, 8.50, and 4.00 ppm, respectively with trace amounts of 3,5-cholestadien-7-one. When fluorescent light was used instead of ultraviolet light with other conditions remained the same, the same species of cholesterol oxides were detected but with lesser amounts.

• Journal of dental hygiene science
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• v.16 no.5
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• pp.349-354
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• 2016

The purpose of this study was to evaluate the efficacy of the newly-developed $Qraypen^{TM}$ (All In One Bio, Korea) system for the diagnosis of early proximal caries by comparing it with the conventional methods of visual inspection and periapical radiography. This study was carried out from July 2015 to April 2016 targeting 32 children aged 7~12 years who visited Y-Dental Clinic for school oral health examinations. Two investigators selected and examined a total of 153 primary molars that had not undergone restorative treatment. Comparisons were carried out between visual inspections, readings of posterior periapical radiography images, and readings of $Qraypen^{TM}$ images. This study revealed that the percentage of interproximal surfaces of primary molar teeth without caries incidence was 83.7% using $Qraypen^{TM}$ imaging and 84.9% using visual inspection and periapical radiography. The differences between the two methods were not statistically significant. Thus, $Qraypen^{TM}$ is expected to be a useful and convenient auxiliary diagnostic device that can facilitate the detection of hidden proximal caries in primary molars.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.189-194
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• 2014

In this study, from a new x-ray detector that combines a columnar CsI:Na scintillation layer with a photosensitive mercuric iodide layer was investigated. In this structure, X-rays are converted into visible light on a thick CsI:Na layer, which is then converted to electric charges in a thin $HgI_2$ bottom layer. The thin coplanar mercuric iodide films as a photosensitive converter requiring only a few tens of volts of bias, associated with a thick columnar coating of phosphor layer, were simulated and designed. The results of this research suggest that the new coplanar x-ray detector with a hybrid-type structure can resolve the following problems: high voltage from the a-Se, and low conversion efficiency from the indirect conversion method. The results of this research suggest that the new CsI:Na/$HgI_2$ x-ray detector with a double-layer type structure can resolve the following problems: high voltage from the direct conversion method, and low conversion efficiency from the indirect conversion method.