• Radiation Oncology Journal
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• v.20 no.1
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• pp.41-52
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• 2002

Purpose : 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. Materials and Methods : The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were peformed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. Results : The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probabiliy. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values $(4\~5\%\;increased)$ for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased $(50\~70\%\;increased)$ for upon extending PTV margins by 2.0 cm. Conclusion : Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.491-498
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• 2022

In our daily life, quality of sleeping is closely related to happiness index. Whether or not people perceive sleep disturbance as a chronic disease, people complain of many difficulties, and in their daily life, they often experience difficulty breathing during sleep. It is very important to automatically recognize breathing-related disorders during a sleep, but it is very difficult in reality. To solve this problem, this paper proposes a mobile-based non-contact sleeping monitoring for health management at home. Respiratory signals during the sleep are collected by using the sound sensor of the smartphone, the characteristics of the signals are extracted, and the frequency, amplitude, respiration rate, and pattern of respiration are analyzed. Although mobile health does not solve all problems, it aims at early detection and continuous management of individual health conditions, and shows the possibility of monitoring physiological data such as respiration during the sleep without additional sensors with a smartphone in the bedroom of an ordinary home.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.324-326
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• 2011

Measuring a biosignal during sleep is an important part of diagnosis and treatment of sleep disorder and also used to determine the general quality of sleep. As in current polysomnography, Contact method, which requires the attachment of electrodes to the skin, is the typical method to measure a biosignal during sleep. The procedure of this test is often considered to be inconvenient and tiresome because it requires attaching the device to the skin for each observation, and also limits free movement throughout the test. For this reason, the research on the acquiring the biosignal information without any attachment of a fixture on the skin is being conducted actively these days. In this study, it is suggested to check the heart rate per minute and the presence of breathing by placing a Piezo, which is a film type of pressure sensor, on the bed.

• Journal of Sensor Science and Technology
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• v.17 no.2
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• pp.133-142
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• 2008

Respiration is induced by muscular contraction of the chest and abdomen, resulting in the abdominal volume change. Thus, continuous measurement of the abdominal dimension enables to monitor breathing activity. Conductive rubber cord has been previously introduced and tested to develop wearable application for respiratory measurements. The present study implemented wireless wearable respiratory monitoring system with the conductive rubber cord in the patient's pants. Signal extraction circuitry was developed to obtain the abdominal circumference changes reflecting the lung volume variation caused by respiratory activity. Wireless transmission was followed based on the zigbee communication protocol in a size of 65mm${\times}$105mm easily put in pocket. Successful wireless monitoring of respiration was performed in that breathing frequency was accurately estimated as well as different breathing patterns were easily recognized from the abdominal signal. $CO_2$ inhalation experiment was additionally performed in purpose of quantitative estimation of tidal volume. Air mixed with $0{\sim}5%\;CO_2$was inhaled by 4 normal males and the respiratory air flow rate, abdominal dimension change, and end tidal $CO_2$ concentration were simultaneously measured in steady state. $CO_2$ inhalation increased the tidal volume in normal physiological state with a correlation coefficient of 0.90 between the tidal volume and the end tidal $CO_2$ concentration. The tidal volume estimated from the abdominal signal linearly correlated with the accurate tidal volume measured by pneumotachometer with a correlation coefficient of 0.88 with mean relative error of approximately 8%. Therefore, the tidal volume was accurately estimated by measuring the abdominal dimension change.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1231-1236
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• 2017

In this study, we developed a system that can change position to improve obstructive sleep apnea. Blocking of the breathing airway caused by obstruction of the apnea, lateral position is provided by the airway to improve the apnea. We used a pressure sensor (FSR402) in the form of an array to determine the position of patient. The air cylinder was controlled to raise and lower the bed. As a result of calculating the pressure difference between the supine position and the lateral position, it was $0.41{\pm}0.30$ and $1.09{\pm}0.73$. In other words, when the patient is lateral position, the difference between the sensor values on the right and left side is large. Therefore, it is confirmed that the system can maintain airway to breath for improvement of obstructive sleep.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.1 no.1
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• pp.1-6
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• 2007

Applying the gyroscopic technology, HeadZmouse has been developed to simulate left and right mouse click, double click, drag and drop, and even a wheel function for navigating web. This device was designed to work on both PC and Macintosh environments using a USB cable. The first time you use this device, you'll find out how much freedom it offers to someone who can't use his or her hands freely. Rather than being tied to your computer, simple manipulation such as blowing an air (breathing) into a sonic sensor can simulate all the functions which standard mouse has, even including a wheel function. Also, a macro-interface device has been developed. By storing repetitive tasks into a memory, you can carry out repetitive tasks just by clicking a button once.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.386-393
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• 1999

Objective : Cardiopulmonary exercise testing in patients with heart and lung problems is used to assess functional capacity, evaluate responses to medical treatment, plan for exercise therapy, assess progression of disease process, and determine prognosis. Particularly in the patients with lung cancer, the exercise pulmonary function test gives significant physiologic assessment of the lung resection candidate. Common exercise modalities are running and cycling. Until now, the comparison of two tests mainly has been done in normal person and patients with cardiac diseases. This study is designed to compare the treadmill and bicycle exercise pulmonary function test in patients with respiratory diseases. Methods : Twenty one patients underwent a progressively incremental exercise test to the symptom-limited stage with the treadmill (Vmax29 Sensor Medics, USA) and the bicycle(model No. 2,900 Sensor Medics, USA) with 7 days apart between the two tests. Measurements were made of the metabolic, cardiorespiratory parameters, blood gases, and symptoms. Results : The results of the treadmill exercise showed significant elevation in the $VO_2$max, VEmax, and anaerobic threshold compared to those of bicycle exercise. In contrast, the results of the breathing and heart rate reserve showed the reverse. Conclusion : These results suggest that the type of exercise should be taken into consideration when interpreting exercise test in patients with respiratory diseases.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.15-22
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• 2019

The purpose of this study is to develop a strain sensor based on a nanoweb by applying electrical conductivity to a polyurethane nanoweb through the use of Graphene. For this purpose, 1% Graphene ink was pour-coated on a polyurethane nanoweb and post-treated with PDMS (Polydimethylsiloxane) to complete a wearable strain sensor. The surface characteristics of the specimens were evaluated using a field emission scanning electron microscope (FE-SEM) to check whether the conductive material was well coated on the surface of the specimen. Electrical properties of the specimens were measured by using a multimeter to measure the linear resistance of the specimen and comparing how the line resistance changes when 5% and 10% of the specimens are tensioned, respectively. In order to evaluate the performance of the specimen, the gauge factor was obtained. The evaluation of the clothing was performed by attaching the completed strain sensor to the dummy and measuring the respiration signal according to the tension using MP150 (Biopac system Inc., USA) and Acqknowledge (ver. 4.2, Biopac system Inc., U.S.A.). As a result of the evaluation of the surface characteristics, it was confirmed that all the conductive nanoweb specimen were uniformly coated with the Graphen ink. As a result of measuring the resistance value according to the tensile strength, the specimen G, which was treated with just graphene had the lowest resistance value, the specimen G-H had the highest resistance value, and the change of the line resistance value of the specimen G and the specimen G-H is increased to 5% It is found that it increases steadily. Unlike the resistance value results, specimen G showed a higher gauge rate than specimen G-H. As a result of evaluation of the actual clothes, the strain sensor made using the specimen G-H measured the stable peak value and obtained a signal of good quality. Therefore, we confirmed that the polyurethane nanoweb treated with Graphene ink plays a role as a breathing sensor.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.122-125
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• 2004

In radiotherapy of tumors in liver, enough planning target volume (PTV) margins are necessary to compensate breathing-related movement of tumor volumes. To overcome the problems, this study aims to obtain patients' body movements by using a moving phantom and an ultrasonic sensor, and to develop respiration gating techniques that can adjust patients' beds by using reversed values of the data obtained. The phantom made to measure patients' body movements is composed of a microprocessor (BS II, 20 MHz, 8K Byte), a sensor (Ultra-Sonic, range 3 cm ${\sim}$3 m), host computer (RS232C) and stepping motor (torque 2.3Kg) etc., and the program to control and operate it was developed. The program allows the phantom to move within the maximum range of 2 cm, its movements and corrections to take place in order, and x, y and z to move successively. After the moving phantom was adjusted by entering random movement data(three dimensional data form with distance of 2cm), and the phantom movements were acquired using the ultra sonic sensor, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using guinea pigs, the real-time respiration gating techniques were drawn by operating the phantom with the reversed values of the data. The result of analyzing the acquisition-correction delay time for the three types of data values and about each value separately shows that the data values coincided with one another within 1% and that the acquisition-correction delay time was obtained real-time (2.34 ${\times}$ 10$^{-4}$sec). This study successfully confirms the clinic application possibility of respiration gating techniques by using a moving phantom and an ultra sonic sensor. With ongoing development of additional analysis system, which can be used in real-time set-up reproducibility analysis, it may be beneficially used in radiotherapy of moving tumors.

• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.24-32
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• 2007

Conductive rubber material was molded in a belt shape to measure respiration. Its resistivity was approximately $0.03{\;}{\Omega}m$ and the resistance-displacement relationship showed a negative exponent. The temperature coefficient was approximately $0.006{\;}k{\Omega}/^{\circ}C$ negligible when practically applied on the abdomen. The conductive rubber belt was applied on a normal male's abdomen with the dimensional change measured during resting breathing. The abdominal signal was differentiated ($F_{m}$) and compared with the accurate standard air flow rate signal ($F_{s}$) obtained by pneumotachometry. $F_{m}$ and $F_{s}$ differed in waveform, but the start and end timings of each breaths were clearly synchronized, demonstrating that the respiratory frequency could be accurately estimated before further processing of $F_{m}$. $F_{m}-F_{s}$ loop showed a nonlinear hysteresis within each breath period, thus 6 piecewise linear approximation was performed, leading to a mean relative error of 14 %. This error level was relatively large for clinical application, though customized calibration seemed feasible for monitoring general variation of ventilation. The present technique would be of convenient and practical application as a new wearable respiratory transducer.