Application of Stereo-Imaging Technology to Medical Field

남경원,박정윤,김인영,김광기 대한의료정보학회 2012 Healthcare Informatics Research Vol.18 No.3

Objectives: There has been continuous development in the area of stereoscopic medical imaging devices, and many stereoscopic imaging devices have been realized and applied in the medical field. In this article, we review past and current trends pertaining to the application stereo-imaging technologies in the medical field. Methods: We describe the basic principles of stereo vision and visual issues related to it, including visual discomfort, binocular disparities, vergence-accommodation mismatch, and visual fatigue. We also present a brief history of medical applications of stereo-imaging techniques, examples of recently developed stereoscopic medical devices, and patent application trends as they pertain to stereo-imaging medical devices. Results: Three-dimensional (3D) stereo-imaging technology can provide more realistic depth perception to the viewer than conventional two-dimensional imaging technology. Therefore, it allows for a more accurate understanding and analysis of the morphology of an object. Based on these advantages, the significance of stereoscopic imaging in the medical field increases in accordance with the increase in the number of laparoscopic surgeries, and stereo-imaging technology plays a key role in the diagnoses of the detailed morphologies of small biological specimens. Conclusions: The application of 3D stereo-imaging technology to the medical field will help improve surgical accuracy, reduce operation times, and enhance patient safety. Therefore, it is important to develop more enhanced stereoscopic medical devices.

한국형 심실 보조 인공심장과 자연심장 간의 counterpulsation 제어 알고리즘의 개발

남경원,최성욱,정진한,김욱은,민병구 대한의용생체공학회 2002 의공학회지 Vol.23 No.1

A Velltricular Assist Device (VAD) 15 used to support the injured natural he柳 · t. 50, when consid鮮ing a control algorithm for VAD, it 15 imPortant to reduce a natural heart '5 load to enhance its recovery condition. To reduce natural heart 's foad, a counterpulsation algorithm 15 used commonly. In this study, we developed a counterpulsation control algorithm for moving: actuator type VAD and tested its usefulness using in vitro MOCK circulatory system. To notice a natural heart 's pumping status, electrocardiogram (ECG) signal was used and as a result of test, the counterpulsation effect between VAD and a natural heart was occurred and Aut0matic Control M0de Trans1tion was 0ccurred pr0periy. Key words : Counterpulsation. Ventricular assist device, Control algorithm, Electrocardiogram 심실보조장치 (ventricular assist device, VAD) 는 그 특성상 손상된 자연심장의 기능을 보조하기 위해서 사용된다. 따라서, 심실보조장치 의 제어 알고리즘을 고려할 때에는 가능한 한 자연심장에 걸리는 부하를 최소한으로 줄여주는 것이 중요하다. 이처럼 자연심장에 걸리는 부하를 줄 여 주기 위 해 가장 일 반적 으로 사용되 는 제 어 방식 이 바로 자연심 장과 심 실보조장치 상호간의 동시 박출을 방지 하는 counterpulsation 제 어 방식 이 다. 실제로 Nanas[ 1」 [이 등은 동물실험을 통해 좌심실이 손상된 상황에서 counterpulsation 장치가 혈류역학적으로 어떠한 영향을 미치는가를 연구하였다. 본 연구에서는, 현재 서울대학교 인공심장연구실과 (주) 바이오메드랩에서 공동으로 개발 중인 이동작동기형 심실보조장지 (AnyHeartT쐬 에 사용할 수 있는 counterpulsation 제 어 알고리 즘을 개 발하고, 개 발된 알고리 즘을 실제 동물 실험 에 적 용하기 에 앞서 모의 순환장 치를 이용하여 개발된 알고리즘의 효용성을 검증하여 보았다. 자연심장의 박출 상태를 실시간으로 파악하기 위해 심전도 (electlocaldiogram, ECG) 신호를 입력으로 받아들여 제어를 수행하는 방식을 채택하였으며, 모의순환장치에서의 샬험 결과 심실보조장치와 자연심장 간의 동시 박출 방지 효과가 정상적으로 일어남을 확인할 수 있었다.

합성환경 하에서의 수중운동체 HILS/MILS 구현 기법 연구

남경원 한국군사과학기술학회 2002 한국군사과학기술학회지 Vol.5 No.2

In this paper, development procedures of an Underwater Vehicle HILS/MILS System in SE(Synthetic Environment) are described. As this System is developed, we can obtain the more powerful tool which can be used to test and verify operational logics and algorithms of an Underwater Vehicle as well as its hardware in various tactical situations.

A New Computerized Diagnostic Algorithm for Quantitative Evaluation of Binocular Misalignment in Patients with Strabismus

남경원,김인영,강호철,양희경,윤창기,황정민,김영재,김태윤,김광기 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.7

Accurate measurement of binocular misalignment between both eyes is important for proper preoperative management, surgical planning, and postoperative evaluation of patients with strabismus. In this study, we proposed a new computerized diagnostic algorithm that can calculate the angle of binocular eye misalignment photographically by using a dedicated three-dimensional eye model mimicking the structure of the natural human eye. To evaluate the performance of the proposed algorithm, eight healthy volunteers and eight individuals with strabismus were recruited in this study, and the horizontal deviation angle, vertical deviation angle, and angle of eye misalignment were calculated and the angular differences between the healthy and strabismus groups were evaluated using the nonparametric Mann뻎hitney test and the Pearson correlation test. The experimental results demonstrated that there was a statistically significant difference between the healthy and strabismus groups (p = 0.015 < 0.05), but there was no statistically significant difference between the proposed method and the Krimsky test (p = 0.912 > 0.05). The measurements of the two methods were highly correlated (r = 0.969, p <0.05). From the experimental results, we believe that the proposed diagnostic method has a potential to be a diagnostic tool that measures the physical disorder of human eye to diagnose the severity of strabismus non-invasively.

심전도 신호를 이용한 이동 작동기형 심실 보조장치와 자연심장 간의 Counterpulsation을 위한 제어 알고리즘의 개발

남경원,김욱은,최성욱,민병구 제주대학교 인공심장이식연구소 2000 인공심장 연구 Vol.1 No.2

본 연구의 목적은 현재 서 물대학교에서 개발중인 이식형 심실보조장치(ventricular assist device, VADI와 자연심장 간의 좌심실 동시 박출 방지를 위한 제어 알고리즘을 개발하고, 개발된 알고리즘을 실제 동물 실험에 적용하기에 앞서 모의순환장치를 이용하여 알고리즘의 효용성을 검증하기 위함이다. 자연심장의 박출 상태를 실시간으로 파악하기 위해 심전도(electrocardiogram, ECG) 신호를 입력으로 받아들여 제어를 수행하는 방식을 채택하였다. 또한, 심실보조장치와 자연심장 간의 좌심실 동시 박출을 방지하고, 동시에 자연심장의 박출량에 무관하게 심실보조장치에서 적정수준 이상의 혈액 박출량이 항상 유지되도록 하는 두 가지 목표를 달성하기 위해 알고리즘을 작성하였다. 이를 위해 심전도 시뮬레이터에서 발생한 신호를 입력으로 받아 자연심장의 현재 박출 상태를 검출하고, 현재 자연심장의 박출 상태에 따라 심실보조장치의 제어 인자들과 사전에 정의된 박출 모드들을 자동적으로 변경하는 방식으로 연구를 수행하였다. 모의순환장치에서의 실험 결과 심실보조장치와 자연심장 간의 동시 박출 방지 章과가 실제로 일어남을 확인할 수 있었으며, 동시에 적정 수준의 박출량 유지를 위해 선택된 박출 모드에 따라 제어 인자들이 자동적으로 변경됨을 확인할 수 있었다. The objectives of this study are to develope control algorithm for counterpulsation between moving-actuator type ventricular assist device and natural heart, and to test its peformance before applying animal experiment using mock circulation system. Electrocardiogram is used to detect the pumping status of the natural heart. Maln obiectives of algorithm are twofold. The one is the counterpulsation between ventricular assist device and natural heart. The other is the maintenance of pumping output above propel level. To do this, we use patient simulator to generate electrocardiogram signal. In the mock test, it is shown that counterpulsation between ventricular assist device and electrocardiogram signal is actually occurred, and that automatic changes of control parameters and pumping modes are occurred to maintain pumping output at proper level.

무지 외반증에 대한 Chevron 절골술의 결과

강창수,남경원 啓明大學校 醫科大學 1999 계명의대학술지 Vol.18 No.3

Many surgical procedures are available for treating the hallux valgus. Of these, the chevron osteotomy is one of the most widely used distal metatarsal osteotomies. We performed chevron osteotomy for hallux valgus on 89 feet in 60 patients. The results were as follows; 1. There were 3 men and 57 women, and the average age at operation was 46 years old. The bilateral hallux valgus deformity was found in 29 patients. 2. The average hallux valgus angle was 34.7 degrees preoperatively and corrected to 15.7 degrees postoperatively. The first-second intermetatarsal angle was 12.9 degrees preoperatively and corrected to 9.7 degrees postoperatively. 3. The metatarsalgia of the great the was completely removed in 67 feet(71%) and in 62 cases(70%), the patients were satisfied with the cosmetic results of the operation.

공압을 이용한 수중운동체의 수압시뮬레이터 설계 연구

전우선,정원지,김원제,남경원 國立 昌原大學校 産業技術硏究所 2000 産技硏論文集 Vol.14 No.-

HILS(Hardware In Loop Simulation) is an effective means of testing unmanned underwater vehicle under extreme operational conditions and a variety of operational environments. In order to verify the vehicle performance under time-varying pressure conditions, a reliable pressure simulator is vital to an integrated system for the HILS. This paper presents the results of design research for the pressure simulator using pneumatic pressure (nitrogen), a high speed solenoid valve and a PWM control method. The test and evaluation results of the pressure simulator show that the simulator can generate an appropriate level of desired pressure with an average error below 1m depth for time-varying pressure change conditions corresponding to vehicle dynamics. In addition, the levels of overshoot and vibration have been shown to be under the requirements of design specifications.

신세포암종 조직에서 암에 특이한 RNase Isozyme과 Inhibitor의 성상에 관한 연구

남경원,강진호,한중수,고재경 한양대학교 의과대학 1996 한양의대 학술지 Vol.16 No.1

Activities of ribonuclease (RNase) and RNAse inhibitor reported to be involved in carcinogenesis process were determined in the renal cell carcinoma tissue. RNase and RNAse inhibitor specific to the cancer were isolated from the renal cell carcinoma tissue. substrate specificity and other properties of th enzyme and enzyme inhibitor were studied and their interaction was investigated. RNase activity in the renal cell carcinoma tissue was significantly dicreased with the use of poly C as substrate and unchanged with the use of RNA as substrate. Ratio of RNA/poly C for RNase activity was higher in the cancer tissue than the control tissue. Activity of RNAse inhibitor was significantly increased and inhibitor/RNAse ratio was markedly higher in the cancer tissue. Proteins in the renal cell carcinoma tissue were separated by a DEAE-cellulose column chromatography into 6 peaks, of which five peak proteins exhibited RNASe and RNase inhibitor activities. Activities of RNase and RNAse inhibitor in for RNASE isozyme fractions except for RNAse isozyme I were lower in the cancer tissue than in the control tissue, but RNA/poly C ratio for RNase activity and inhibitor/RNase ratio were higher in th cancer tissue than the control tissue than the control, and RNA/poly C ratio for the RNase activity and inhibitor/RNA ratio were markedly higher in the isozyme I fraction of the cancer tissue. The RNase isozyme I isolated from the renal cell carcinoma tissue was highly active toward poly AC and AU, the activity being decreased toward poly C,AU, U, RNA, poly CIU, CU, CI in order. Noactivity was observed toward poly AGU, AG, GU, poly dA and dT. Substrate specificity of the RNAse isozyme I from the cancer tissue was similar to that of the isozyme I from the control tissue in pattern but differ in that relative activity toward poly CU, AC, ACU, U and RNA was higher in the isozyme I from the cancer tissue than from the control tissue. The present study were summerized that (1) RNAse acitivity was significantly decreased and RNAse inhibitor activity was increased in the renal cell carcinoma tissue, (2) ratio of RNA/poly C for RNAse activity and inhibitor/RNase ratio were higher in the RNAse isozyme I from the renal cell carcinoma tissue than that from the renal control tissue and (3) substrate specificity was different between the two tissues. These results indicatd that the RNase isozyme I isolated from the renal cell carcinoma tissue is specific to the cancer and that the isozyme appears to be regulated strongly by the RNase inhibitor, suggesting an important role of the isozyme in carcinogenesis of the renal cell carcinoma.

A Comparison of Frequency-invariant Beamforming Algorithms for Hearing Aids: Differential Microphone-based Beamformers and the Broadband Beamformer

조경원,남경원,이준창,홍성화,See Youn Kwon,Jonghee Han,Dongwook Kim,이상민,김인영 대한의용생체공학회 2014 Biomedical Engineering Letters (BMEL) Vol.4 No.2

Purpose Recently, some research groups have suggested thepossibility of using the broadband beamformer (BBF)algorithm for hearing aid applications. However, there havebeen no previous reports to have quantitatively evaluatedthe relative performance between conventional differentialmicrophone (DM)-based frequency-invariant beamformingalgorithms and the broadband beamformer. Methods In this study, we evaluated the performance ofDM-based beamformer algorithms and the BBF algorithm invitro using the four objective indices of signal-to-noise ratio(SNR), perceptual evaluation of speech quality (PESQ),noise distortion (Cbak) and weighted spectral slope (WSS) ina non-reverberant environment. Results The experimental results showed that the DM-basedalgorithms were superior in terms of SNR, WSS and Cbak,and the BBF algorithm was superior in terms of PESQ. Conclusions Considering the limited performance of hearingaid processors and the experimental results, DM-basedfrequency-invariant algorithms with a first-order compensation filter are more feasible for real hearing aids. However,additional in vitro and clinical evaluations are required to moreaccurately verify the clinical feasibility of these algorithms.

3D 프린팅 기술의 의료기기 수리 적용에 대한 국내 규제 이슈 및 기술적 적합성 평가

윤성욱,남경원,Yun, Sung Uk,Nam, Kyoung Won 대한의용생체공학회 2020 의공학회지 Vol.41 No.2

In large-scale hospitals, the department of biomedical engineering should always provide quick repair service for damaged medical devices to guarantee continuous patient treatment. However, in actual circumstances, there are so many time-consuming issues that delays device repair for weeks or even months; therefore, it is required to prepare alternative ways for quick repair service. In this study, we first mentioned about the regulation issues in Korea about the 3D printing-based medical device repair, and then introduced the results of our preliminary study that evaluated the feasibility of 3D printing-based medical device repair before real-field application. Results of the study demonstrated that, in all of the 23 cases, parts for repair that were manufactured by 3D-printing were successfully fixed and connected to the main body of the original device, and showed sufficient rigidity for protecting internal parts of the device. Considering the experimental results, medical device repair by applying 3D printing technology can be a promising alternative in cases when regular repair process is not available or takes too much time.