• The KIPS Transactions:PartA
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• v.10A no.2
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• pp.149-156
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• 2003

In the latest medical world, the attempt of reconstructing anatomical human body system using computer graphics technology awakes people's interests. Actually, this trial has been made in dentistry too. There are a lot of practicable technology fields using computer graphics in dentistry For example, 3D visualization and measurement of dental data, detection of implant location, surface reconstruction for restoring artificial teeth in prostheses and relocation of teeth in orthodontics can be applied. In this paper, we propose methods for definitely detecting the geometric features of teeth such as cusp, ridge, fissure and pit, which have been used as most important characteristics in dental applications. The proposed methods are based on the approximate curvatures that are measured on a 3D tooth model made by scanning an impression. We also give examples of the geometric features detected by using the proposed methods. Comparing to other traditional methods visually, the methods are very useful in detecting more accurate geometric features.

• Journal of Radiation Protection and Research
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• v.4 no.1
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• pp.5-13
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• 1979

A simple method for determining the airborne concentration of radon daughter products has been developed, which is based on gross alpha counting of the air filter collections at several time intervals after completion of air sampling. The concentration of each nuclide is then obtained from an equation involving the alpha disintegrations, the sampling time, and the known numerical coefficients. The state of radioactive disequilibrium is also investigated. The atmosphere sampled in the TRIGA Mark-III reactor room was largely in disequilibrium. The extent of radioactive disequilibrium between radon daughter products seems likely depend on sampling times associated with turbulence conditions. The data obtained here will certainly provide useful information on the evaluation of internal exposure and calibration of effluent monitoring instruments.

• Progress in Medical Physics
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• v.17 no.3
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• pp.173-178
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• 2006

The purpose of this study was to evaluate the radiation dose for clinical PET/CT protocols in clinical environments using Alderson phantom and TLDs. Radiation doses were evaluated for both Philips GEMINI 16 slice PET/CT system and GE DSTe 16 slice PET/CT system. Specific organ doses with $^{137}Cs$ transmission scan, high quality CT scan and topogram in philips GEMINI PET/CT system were measured. Specific organ doses with CT scan for attenuation map, CT scan for diagnosis and topogram in GE DSTe PET/CT system were also measured. The organs were selected based on ICRP60 recommendation. The TLDs used for measurements were selected for within an accuracy of ${\pm}5%$ and calibrated in 10 MV X-ray radiation field. The effective doses for $^{137}Cs$ transmission scan, high qualify scan, and topogram in Philips GEMINI PET/CT system were $0.14{\pm}0.950,\;29.49{\pm}1.508\;and\;0.72{\pm}0.032mSv$ respectively. The effective doses for CT scan to make attenuation map, CT scan to diagnose and topogram in GE DSTe PET/CT system were $20.06{\pm}1.003,\;24.83{\pm}0.805\;and\;0.27{\pm}0.008mSv$ respectively. We evaluated the total effective dose by adding effective dose for PET Image. The total PET/CT doses for Philips GEMINI PET/CT (Topogram+$^{137}Cs$ transmission scan+PET, Topogram+high qualify CT+PET) and GE DSTe PET/CT (Topogram +CT for attenuation map+ PET, Topogram+diagnostic CT+ PET) are $7.65{\pm}0.951,\;37.00{\pm}1.508,\;27.12{\pm}1.003\;and\;31.89{\pm}0.805mSv$ respectively. Further study may be needed to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with good image qualify.

• Progress in Medical Physics
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• v.19 no.4
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• pp.209-218
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• 2008

According to improved radiation therapy technology such as IMRT and proton therapy, the accuracy of patient alignment system is more emphasized and IGRT is dominated research field in radiation oncology. We proposed to study the feasibility of cone-beam CT system using simple x-ray imaging systems for image guided proton therapy at National Cancer Center. 180 projection views ($2,304{\times}3,200$, 14 bit with 127 ${\mu}m$ pixel pitch) for the geometrical calibration phantom and humanoid phantoms (skull, abdomen) were acquired with $2^{\circ}$ step angle using x-ray imaging system of proton therapy gantry room ($360^{\circ}$ for 1 rotation). The geometrical calibration was performed for misalignments between the x-ray source and the flat-panel detector, such as distances and slanted angle using available algorithm. With the geometrically calibrated projection view, Feldkamp cone-beam algorithm using Ram-Lak filter was implemented for CBCT reconstruction images for skull and abdomen phantom. The distance from x-ray source to the gantry isocenter, the distance from the flat panel to the isocenter were calculated as 1,517.5 mm, 591.12 mm and the rotated angle of flat panel detector around x-ray beam axis was considered as $0.25^{\circ}$. It was observed that the blurring artifacts, originated from the rotation of the detector, in the reconstructed toomographs were significantly reduced after the geometrical calibration. The demonstrated CBCT images for the skull and abdomen phantoms are very promising. We performed the geometrical calibration of the large gantry rotation system with simple x-ray imaging devices for CBCT reconstruction. The CBCT system for proton therapy will be used as a main patient alignment system for image guided proton therapy.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.123-131
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• 2008

In Oriental medicine, the status of a tongue is the important indicator to diagnose the condition of one's health like the physiological and the clinicopathological changes of internal organs in a body. A tongue diagnosis is not only convenient but also non-invasive, and therefore widely used in Oriental medicine. However, the tongue diagnosis is affected by examination circumstances like a light source, patient's posture, and doctor's condition a lot. To develop an automatic tongue diagnosis system for an objective and standardized diagnosis, segmenting a tongue region from a facial image captured and classifying tongue coating are inevitable but difficult since the colors of a tongue, lips, and skin in a mouth are similar. The proposed method includes preprocessing, over-segmenting, detecting the edge with a local minimum over a shading area from the structure of a tongue, correcting local minima or detecting the edge with the greatest color difference, selecting one edge to correspond to a tongue shape, and smoothing edges, where preprocessing consists of down-sampling to reduce computation time, histogram equalization, and edge enhancement, which produces the region of a segmented tongue. Finally, the systematic procedure separated only a tongue region from a face image with a tongue, which was obtained from a digital tongue diagnosis system. Oriental medical doctors' evaluation for the results illustrated that the segmented region excluding a non-tongue region provides important information for the accurate diagnosis. The proposed method can be used for an objective and standardized diagnosis and for an u-Healthcare system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.493-503
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• 2018

Recently, as living standards have improved, many people are becoming more interested in health, and self-training is increasing through exercise to prevent and manage pre-illness. In general, an imbalance of muscles causes asymmetry of posture, which can cause various diseases by accompanying an adjustment force, circulation action, displacement of internal organs, etc.. In this study, the development of fitness software that can be self - training among smart wears has attracted considerable attention in recent years. In this study, a technology was proposed for the commercialization of self - trainer fitness wear by a simulation through Android - based applications. Self - trainer fitness software was developed by combining a conductive polymer, fashion design, sewing, and electric and electronic technology to monitor the unbalance of the muscles during exercise and make smart wear that can calibrate the asymmetry by oneself. In particular, a polymer sensor was fabricated by deriving the optimal MWCNT concentration, and the electrode signal was collected by attaching the electrode to the optimal position, where the electrode signal line using the conductive fiber was designed and attached to collect the signal. A signal module that converts the bio-signals collected through electrical signal conversion and transmits them using Bluetooth communication was designed and manufactured. Self-trainer fitness software that can be commercialized was developed by combining noise cancellation with Android-based self-training application using a software algorithm method.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.2
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• pp.129-136
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• 1991

The fibrin sealant was first designed as an alternative to surgical suture for the purpose of surface-to-surface union especially in parenchymal organs like the liver, spleen and kidney. The clinical application of currently used fibrin sealant was first introduced in 1972. The fibrin sealant consists of principal two components; lyophilized human fibrinogen and bovine thrombin. The fibrinogen component also contains coagulation factor XIII. A solution of aprotinin, an inhibitor of fibrinolysis is used to dissolve the fibrinogen and to provide the first component, and a solution of calcium chloride is also used to provide the second component. From July to December in 1990, during 6 months, we used fibrin sealant in the 28 patients of 33 various cases, in the following ways; supportive application of fibrin sealant after free autogenouse nerve graft for the repair of inferior alveolar nerve, facial nerve or accessory nerve, treament of hemangioma or lymphangioma to thrombosize and lead to the tumor shrinking, skin grafting to stimulate the adhesion and tissue repair, bone grafting in the patients of cleft alveolus, mandibular reconstruction or orthognathic surgery to facilitate the knitting of bone chips, tissue adhesion after tumor resection, radical neck dissection or flap reconstructions, and supportive adhesion of external auditory cannal after TMJ surgery via postauricular approach. No adverse effects were observed, none of the patients developed hepatitis or other blood transmitted disease, and the wound healing were acceptable.

• Journal of Radiation Protection and Research
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• v.15 no.1
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• pp.9-13
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• 1990

1959년 한국원자력연구소가 창립됨과 동시에 &Health Physics&, 즉 보건물리라고 하는 명칭과 조직이 탄생되어, 방사선안전관리의 실무와 보건물리의 연구가 시작되었다. 최초 10년간은 선진제국의 보건물리분야의 연구와 기술을 추적하여 우리나라의 방사선안전관리 기술의 기초를 다지는 시기로서 개인방사선모니터링기술, 환경방사선(능) 모니터링기술 및 방사선방어용계측기기의 교정기술 개발에 중점을 두고 연구개발이 추진되었으며, TRIGA Mark-II 연구용원자로의 가동에 따라 원자로 생체차폐체의 건전성 검증에 관한 유익한 방사선량 측정자료도 얻게 되었다. 즉 이 기간은 방사선안전관리의 체제정비 및 기초기술 확립에 노력한 기간이었다. 1970년대는 원자력 연구개발에 대한 기본방향과 정책의 변경등으로 보건물리 연구조직은 방사선안전관리, 환경연구 그리고 방사화학분야로 분산되었으며, 그로인하여 연구개발활동은 거의 정체되어 겨우 방사선안전관리 실무만이 그 명맥을 유지하였다. 그 결과 우리나라 방사선안전관리 및 그와 관련된 연구개발의 기반이 흔들리게 되었으나, 그러한 환경하에서도 방사선량측정평가기술, 방사선차폐설계기술 및 원자로사고시 피폭선량평가기술의 선진화에 필요한 지식을 얻었으며, 방사선 안전관리에 유익한 실무경험도 축적하게 되었다. 1980년대는 통합된 원자력 연구개발체제의 구축으로 방사선작업종사자 및 일반공중의 피폭저감화 기술개발에 필요한 각종 최신기술을 도입하였고, 관리업무에 있어서도 측정의 정확도와 신뢰성향상 및 새로운 관리기술의 개발에 많은 노력을 한 결과, 유익한성과를 얻게된 기간이다. 특히, 이 기간은 방사선안전관리기술의 선진화를 위한 지식이 축적되어 90년대의 방사선안전관리기술자립화를 위한 전환기로서, 이와같이 축적된 기술은 원자력의 평화적 이용에 크게 기여할 것으로 기대된다.서 dithiothreitol를 투여한 군에서는 우라늄단독투여군에 비해 cretinine의 배설이 상당히 증가하였다(P<0.05). 6. 우라늄오염에 의한 신장의 소견에 있어 우라늄단독투여군은 근위곡세뇨관상피의 공포화 및 종창, microvilli와 brush border의 손실, 세뇨관 상피의 괴사가 관찰되었으며, 간장의 충혈, 중심성 괴사 및 모세관 확장증도 관찰되었다. 그리고 sodium bicarbonate와 생리적 식염수를 병행투여한 군과 우라늄을 투여하고 30분이 지나서 dithiothreitol를 투여한 군에서는 우라늄 단독투여군에 비해 높은 방호효과가 관찰되었으나 다른 실험군에서는 큰 효과가 없는 것으로 나타났다. 결론적으로 우라늄의 체내오염시에는 sodium bicarbonate와 생리적 식염수를 가능한 빨리 병행투여하거나 dithiothreitol을 체내오염후 30분이 지나서 투여하는 방법이 우라늄오염에 대한 제염에 매우 유효할 것으로 생각되며, 특히 우라늄에 의한 인체장해를 유의하게 경감시켜줄 것으로 사료되었다.내의 어떤 부위와도 관계가 되는 것으로 간주되는데 이것이 $(^3H)$ QNB가 $(^3H)$ NMS보다 높은 최대 결합능력 $(B_{max})$을 나타낼 이유이다. (b) 두 종류의 다른 제제에서 우리는 같은 양상의 결과를 관찰하었기에 결점이 많은 homogenates 제제보다는 intact cell aggregates 제제를 수용체 연구에 대한 새로운 실험모형(experiment model)으로 사용할 수 있는 가능성을 제시하고자 한다.$가 38.8%로 가장 많고, 그 다음이 ${\ulcorner}$l9세(歲)이후${\lrcorner}$가 25.2%로서 전체

• Progress in Medical Physics
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• v.16 no.4
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• pp.161-165
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• 2005

The CT number corresponds to electron density and its influence on dose calculation was studied. Five kinds of CT scanners were used to obtain Images of electron density calibration phantom (Gammex RMI 467), Then the differences between CT numbers for each scanners were ${\pm}2\%$ In homogeneous medium and $9.5\%$ in high density medium. In order to Investigate the influence of CT number to dose calculation, patients' thoracic CT images were analyzed. The maximum dose difference was $0.48\%$ for each organ. It acquired the phantom Images inserted high density material in the water phantom. Comparing the doses calculated with CT Images from each CT scanner, the maximum dose difference was $2.1\%$ in 20 cm in depth. The exact density to CT number conversion according to CT scanner is required to minimize the uncertainty of dose depends on CT number Especially the each hospital with various CT scanners has to discriminate CT numbers for each CT scanner. Moreover a periodic quality assurance is required for reproducibility of CT number.

• Progress in Medical Physics
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• v.17 no.2
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• pp.89-95
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• 2006

The purpose of this study was to evaluate the radiation doses during CT transmission scan by changing tube voltage and tube current, and to estimate the radiation dose during our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan. Radiation doses were evaluated for Philips GEMINI 16 slices PET/CT system. Radiation dose was measured with standard CTDI head and body phantoms in a variety of CT tube voltage and tube current. A pencil ionization chamber with an active length of 100 mm and electrometer were used for radiation dose measurement. The measurement is carried out at the free-in-air, at the center, and at the periphery. The averaged absorbed dose was calculated by the weighted CTDI ($CTDI_w=1/3CTDI_{100,c}+2/3CTDI_{100,p}$) and then equivalent dose were calculated with $CTDI_w$. Specific organ dose was measured with our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan using Alderson phantom and TLDs. The TLDs used for measurements were selected for an accuracy of ${\pm}5%$ and calibrated in 10 MeV X-ray radiation field. The organ or tissue was selected by the recommendations of ICRP 60. The radiation dose during CT scan is affected by the tube voltage and the tube current. The effective dose for $^{137}Cs$ transmission scan and high qualify CT scan are 0.14 mSv and 29.49 mSv, respectively. Radiation dose during transmission scan in the PET/CT system can measure using CTDI phantom with ionization chamber and anthropomorphic phantom with TLDs. further study need to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with same image qualify.