• Biomedical Engineering Letters
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• 제8권4호
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• pp.383-392
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• 2018

For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.

• 대한의생명과학회지
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• 제27권1호
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• pp.35-43
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• 2021

Human Sapovirus (HuSaV) is one of the major causes of acute gastroenteritis in humans, and it is used as a molecular diagnostic technique based on polymerase chain reaction (PCR) from humans, food, shellfish, and aquatic environments. In this study, the HuSaV diagnosis technique was used in an aquatic environment where a number of PCR inhibitors are included and pathogens, such as viruses, are estimated to exist at low concentration levels. HuSaV-specific primers are improved to detect 38 strains registered in the National Center for Biotechnology Information (NCBI). The established optimal condition and the composition, including the RT-nested PCR primers and SL® Non-specific reaction inhibitor, were found to have 100 times higher sensitivity based on HuSaV plasmid than the previously reported methods (100 ag based on HuSaV plasmid 1 ng/μL). Through an artificial infection test, the developed method was able to detect at least 1 fg/μL of HuSaV plasmid contaminated with total nucleic acid extracted from groundwater. In addition, RT-nested PCR primer sets for HuSaV detection can react, and a positive control is developed to verify false positives. This study is expected to be used as a HuSaV monitoring method in the future and applied to the safety response to HuSaV from water environments.

• Physical Therapy Rehabilitation Science
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• 제12권1호
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• pp.43-47
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• 2023

Objective: To present a case study of a 69-year-old woman with COVID-19 who developed neurological complications due to Extracorporeal Membrane Oxygenation (ECMO) therapy and highlight the importance of daily neurological examinations and rehabilitation in the early detection and management of ECMO-related neurological complications in an isolation ICU. Design: A case report Methods: The patient received ECMO therapy, followed by neurological monitoring and rehabilitation in an isolation ICU. Daily neurological examinations were conducted to monitor the patient's neurological symptoms. Computed tomography was performed to confirm the presence of a hematoma in the left hamstring, which was identified as the cause of the neurological complication. Ultrasound-guided aspiration was immediately performed, and sciatic neuropathy predominantly involving the peroneal division was identified after aspiration. Results: Successful recovery was made possible by the early detection of neurological complications and rehabilitation in an isolation ICU. Although electrodiagnostic tests were not performed due to limited access to the isolation ICU, the appropriate intervention time could be determined through daily neurological examinations and rehabilitation, thereby minimizing neurological sequelae. Conclusions: ECMO-related neurological complications are well known, and their recognition in the ICU can be challenging. The presented case highlights the importance of daily neurological examinations and rehabilitation in the early detection and management of ECMO-related neurological complications in an isolation ICU, which can minimize neurological sequelae.

• 대한의생명과학회지
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• 제30권1호
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• pp.24-31
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• 2024

Mercury is a chemical pollutant widely present in the environment. Humans are generally exposed to mercury in the form of organic Hg (methylmercury) through the consumption of seafood. Koreans enjoy eating fish therefore blood mercury concentration is usually higher than in developed countries. By investigating blood mercury concentration according to the frequency of seafood consumption and sociodemographic factors, we aimed to identify recent trends in blood mercury concentration in Korean adults. This study was conducted using KoNEHS cycle 4 (2018~2020) from the National Institute Environmental Research Survey. The geometric mean concentration of blood mercury of the subjects was 2.959 (±1.018) ㎍/L, which was significantly higher in men than in women. It was observed that as the frequency of fish and shellfish consumption increased, the blood mercury concentration increased. In adjusted logistic regression, fish consumption was associated with 36.7% increased risk of blood mercury levels [Odds ratio, 1.367; 95% confidence interval (CI), 1.246~1.500], and shellfish consumption was associated with 26.5% increased risk of blood mercury levels [Odds ratio, 1.265; 95% confidence interval (CI), 1.134~1.410]. Blood mercury concentration was also found to increase as the socioeconomic level increased. In conclusion, the geometric mean concentration of blood mercury was increased compared to the one in the 3rd KoNEHS (2015~2017) and seafood consumption and socioeconomic level were still significantly associated with increasing blood mercury concentration in Korea. Therefore, it is necessary to encourage healthy seafood consumption habits and conduct continuous monitoring considering various factors to reduce blood mercury levels.

• 감성과학
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• 제18권4호
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• pp.25-34
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• 2015

본 연구에서는 전도성 직물을 기반으로 동작 센서로 구현하여 팔의 굽힘, 폄 동작에 따른 센서의 전기저항의 변화를 측정, 분석함으로써 관절 동작을 효과적으로 측정 할 수 있는 직물 센서의 요건을 탐색하였다. 이를 위해 두 가지 편직물인 'L'직물과 'W'직물 양면에 Single Wall Carbon Nano-Tube(SWCNT) 코팅을 한 후 이를 다양한 형태로 후가공하여 직물 센서를 개발하고 암 밴드에 부착하였다. 직물 센서는 코팅용 바탕 직물의 종류(2가지), 센서의 부착 방법(2가지), 센서의 layer 수(2가지), 센서의 길이(3가지), 센서의 너비(2가지)의 총 48개로 구성되었다. Con-Trex MJ에 48개의 암 밴드를 입힌 인체 모형 팔을 대상으로 직물 동작 센서의 성능을 평가하였다. 인체 모형 팔에 입혀진 총 48개의 암 밴드 각각에 대해서 frequency: 0.5Hz, ROM: $20^{\circ}{\sim}120^{\circ}$ 에서 굽힘과 폄 동작을 반복하도록 조정하였고, 48개 각 사례 당 세 세트(set)씩 반복 측정한 전압값을 기록하였다. 전압값을 peak-to-peak voltage(Vp-p)의 base line의 균일성, 동일 세트 내 Vp-p의 균일성, 세 세트 간의 Vp-p의 균일성을 기준으로 평가하고 분석한 결과, SWCNT 코팅된 'L' 직물을 두 겹으로 구성하여 열고정 방식으로 부착한 $50{\times}5mm$, $50{\times}10mm$, $100{\times}10mm$ 크기의 직물 센서와, SWCNT 코팅된 'W' 직물을 두 겹으로 구성하고 열고정 방식으로 부착한 $50{\times}10mm$ 크기의 직물 센서가 전체 변화율 5%이내의 가장 균일하고 안정적인 신호값을 나타내었다. 이상의 연구 결과를 통해 SWCNT 코팅 소재를 다양한 형태로 가공해 직물 센서로 구현했을 때 인체의 사지 동작을 측정할 수 있는 센서로서 적합함을 확인하였고, 최적의 센서 형태를 규명하였다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.315-319
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• 1996

We have developed a prototype patient monitoring system including module-based bedside units, interbed network, and central stations. A bedside unit consists of a color monitor and a main CPU unit with peripherals including a module controller. It can also include up to 3 module cases and 21 different modules. In addition to the 3-channel recorder module, six different physiological parameters of ECG, respiration, invasive blood pressure, noninvasive blood pressure, body temperature, and arterial pulse oximetry with plethysmogaph are provided as parameter modules. Modules and a module controller communicate with up to 1Mbps data rate through an intrabed network based on RS-485 and HDLC protocol. Bedside units can display up to 12 channels of waveforms with any related numeric informations simultaneously. At the same time, it communicates with other bedside units and central stations through interbed network based on 10Mbps Ethernet and TCP/IP protocol. Software far bedside units and central stations fully utilizes gaphical user interface techniques and all functions are controlled by a rotate/push button on bedside unit and a mouse on central station. The entire system satisfies the requirements of AAMI and ANSI standards in terms of electrical safety and performances. In order to accommodate more advanced data management capabilities such as 24-hour full disclosure, we are developing a relational database server dedicated to the patient monitoring system. We are also developing a clinical workstation with which physicians can review and examine the data from patients through various kinds of computer networks far diagnosis and report generation. Portable bedside units with LCD display and wired or wireless data communication capability will be developed in the near future. New parameter modules including cardiac output, capnograph, and other gas analysis functions will be added.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.160-168
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• 2014

Continuous body temperature monitoring is useful and essential in diverse medical procedures such as infection onset detection, therapeutic hypothermia, circadian rhythm monitoring, sleep disorder assessment, and gynecological research. However, the existing thermometers are too invasive or intrusive to be applied to long-term body temperature monitoring. In our previous study, we invented the bi-medium deep body thermometer which can noninvasively and continuously monitor deep tissue temperature. And the ratio of thermal resistances expressed as K-value should be obtained to estimate body temperature with the thermometer and it can be different under various measurement environments. Although the device was proven to be useful through preliminary simulation test and small group of human study, the experimental environment was restrictive in our previous approach. In this study, a finite element simulation was executed to obtain the K-value and evaluate the accuracy of bi-medium thermometer under various measurement environments. In addition, K-value estimation equation was developed by analyzing the influence of 5 measurement environmental factors (medium length, medium height, tissue depth, blood perfusion rate, and ambient temperature) on K-value. The results revealed that the estimation accuracy of bi-medium deep body thermometer based on computer simulation was very high (RMSE < $0.003^{\circ}C$) in various measurement environments. Also, bi-medium deep body thermometer based on K-value estimation equation showed relatively accurate results (RMSE < $0.3^{\circ}C$) except for one case. Although the K-value estimation technology should be improved for more accurate body temperature estimation, the results of finite element simulation showed that bi-medium deep body thermometer could accurately measure various tissue temperatures under diverse environments.

• 대한의용생체공학회:의공학회지
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• 제16권2호
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• pp.175-182
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• 1995

태아 심음을 측정하기 위한 기존의 자기상관 함수 법은 처리과정이 간편한 반면에 많은 문제점을 가지고 있다. 초음파 도플러 신호가 열악할 경우 고전적인 자기상관 함수 법은 문턱 값의 선정과 창 함수 크기에 매우 민감하다. 특히 데이터 손실이 생길 때 정확한 태아 심박동 수를 찾기가 어렵다. 이들 문제점들을 보완하기 위하여 초음파 도플러 신호로부터 정확한 태아 심박동 수를 찾는 고해상 피치검출 알고리듬이 제안되었다. 이 알고리듬은 자기상관 함수법 보다 정확하고, 잡음에 강하며, 높은 신뢰성을 갖으나 계산량이 많아 실시간 처리가 어렵다. 본 논문에서는 실시간 처리에 적합한 새로운 태아 심음 추출 알고리듬을 제안하고, 제안된 알고리듬을 적용한 실시간 태아 심음 감시시스템에 관하여 연구하였다.

• 전기학회논문지
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• 제62권10호
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• pp.1444-1450
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• 2013

Esophageal stethoscope is used for monitoring the heart sounds and breath sounds of patients during surgery under a general anesthesia. Recently, an electronic esophageal stethoscope (EES)[1] has been developed for the purpose of real-time monitoring these information visually. This system uses only a microphone as the sound sensor. A drawback of the EES system is that it may be difficult to distinguish the first sound ($S_1$) and the second sound ($S_2$) of heart, because their periods are irregular depending on patients. In this paper, we propose an improved EES system in which the infrasound is measured by adding a pressure sensor as well as a sound sensor. We investigate some correlations between the infrasound and characteristics of the heart sound. The proposed system has been tested on 15 patients. The results show that the new system is capable of detecting the first sound more reliably and easily determining the heart rate and breathing period.

• 대한의용생체공학회:의공학회지
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• 제12권4호
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• pp.235-242
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• 1991

This research has reported that the selection and assessment of treatment in anxiety disorders depend to a large extend on patient reports of somatic symptomatology. However, the correspondence between such reports and actual physiological data Is unknown as the physiological measures used were taken in laboratory. The purpose of the ambulatory momboring device is, therefore, to present for analysis physiological data derived from the sub jects during their daily activities. The physiological parameters of interest are heart rate, respiratory rate, skin conductance level/response, skin temperature, and activity level. This device had an microcomputer based data acquisition unit, Interfaced to it for the purpose of data collection. The data is collected usually over a period of 12 hours. The data from the ambulatory monitoring device can be used to assess the psychophysiology of anxiety in the field. The data from the device will also reveal if patients who report different sets of symptoms differ physiologically too. Thls will help physicians for the right kind of treatment and also solve the many uncertainties that have existed thus far in quantizing anxiety.