• Radiation Oncology Journal
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• 제7권2호
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• pp.213-225
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• 1989

An analysis has been made of two hundred seven patients who were treated at the department of Radiation Oncology of Korea University Hospital for lung cancer from January 1981 through December 1986. There were 137 patients of nonsmall cell carcinoma (137/207, 66%), 26 patients of small cell carcinoma (26/207, 12.5%) and 44 patients of unproven histology. By aims of treatment, there were 104 patients (104/207, 50%) treated for cure, 89 patients (89/207, 42.9%) for palliation and 14 patients treated postoperatively. In 22 out of 207 patients, chemotherapy was done with radiotherapy, 12 of which were patients with small cell carcinoma. Stage II patients were 49 (49/207, 23.6%), stage III patients were 157 (157/207, 75.8%) and one patient had an occult cancer The tumor was initial Iy measured by CAT scan and chest X-rays in the 165 (165/207, 79.7%) patients, among which 117 patients had tumor diameter more than 5cm and 48 patients less than 5cm. Radiation therapy was given with Cobalt 60 teletherapy unit and the treatment volume encompassed primary tumor and the mediastinum. For curative aim, daily tumor dose of 180 cGy was given up to the range of 5,400~6,120cGy/30~34F/6~7 week period and for palliative aim, daily tumor dose of 300 cGy was given up to the range of 3,600~4,500 cGy/12~15F/2~3 week period. Postoperatively, mediastinum was treated for total dose of 5,040 cGy/28F/5.5 week period. 123 patients (123/207, 59%) were followed up after completion of radiotherapy for 14 months to 7 years. Local tumor response to the irradiation was measured by chest X-ray taken at one month follow up and was evaluated for response rate, if they were regressed more than 50% or less than 50% of the initial tumor size. The treatment results were as follows; 1. The median survival time was 8.5 months and survival rates for 1 year, 2 year and 5 year was 25%, 3.5% and 1% of nonsmall cell lung ca of 74 evaluable patients. 2. More than 50% of local tumor response rate was obtained in about half of overall cases; 90.5% for small cell ca, 50% for squamous cell ca, 25% for adenoca and 57% for large cell ca. 3. Response rate more than 50% was seen in the 50% of the patient group with tumor diameter more than 5cm and in the 55% of those with tumor diameter less than 5cm. 4. By total raidation dose given, patient group which was given 5,400~6,120 cGy equivalent dose or higher showed tumor response rate more than 50% in 53% of the patients, whereas the group with dose less than 5,400cGy equivalent, in 25% of the patients. 5. Survival rate for 6 month, 1 year and 2 year was compared between the group of local tumor response rate more than 50% vs. group with response rate less than 50%; 74% vs. 43%, 33% vs, 23%, 10% vs. 1%, respectively. 6. Local failure was seen in 21%(44/207) of the patients, which occured mostly within 15 months after completion of radiation therapy. Distant metastases were seen in 49.7%(103/207) of the patients, of which 43 cases were found before initiation of radiotherapy. The most common metastatic sites were bone and brain. In this sutdy, 1 year,2 year and S year survival rates were somewhat poor compared to the other studies. It mainly seems to be due to the poor general status of the patients and the far-advanced stage of the disease. In nonsmall cell cancer patients who had limited local disease and had small primary tumor size, we observed better local response. In addition, dose higher than 6,000 cGy group showed better tumor control than lower dose group. Survival rate was better for the local control group. For imporvement of local control of the lung cancer and hence, the survival of the patients with lung cancer, proper radical radiotherapy with high dose for localized disease is needed. New modality of treatment such as high LET beam in radiation therapy or drugs for the advanced disease as well as early diagnosis is also needed.

• Radiation Oncology Journal
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• 제16권4호
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• pp.441-446
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• 1998

목적 : 식도암의 빈도는 계속 증가하고 있다. 근치적 수술이 가장 적절한 치료방법으로 알려져 있으나 수술의 대상이 되는 환자는 많지 않으며 방사선치료가 중요한 역할을 하고 있다. 저자들은 방사선치료만으로 치료를 받은 식도암 환자를 대상으로 후향적 분석을 시행하였다. 대상 및 방법 : 1979년 6월에서 1992년 12월까지 289명의 식도암 환자가 서울대학교병원 치료방사선과에서 치료를 받았다. 이 중에서 84명은 다음의 이유로 분석대상에서 제외되었다; 쇄골상림프절 외의 원격전이 22명, 4500cGy 미만의 불완전 방사선치료 52명, 추적관찰 불가능 10명. 따라서 205명이 이 분석의 대상이며, 생존한 환자의 추적관찰 기간은 77개월에서 180개월이었다. AJCC 분류법에 의한 병기 분포는 I기 2명, IIA기 104명, IIB기 26명, III기 48명, IV기 25명이었다. 모든 환자는 방사선치료만 시행 받았다. 방사선치료 선량의 범위는 4500 cGy에서 6980cGy까지로 중앙값은 5940cGy 였다. 결과 : 모든 환자의 생존기간의 중앙값은 11개월이었고, 2년과 5년 및 10년 생존률은 각각 22.4$\%$와 10.2$\%$ 및 5.3$\%$ 였다. 대부분의 치료 실패는 국소재발이었다. 재발한 169명의 환자 중에서 111명은 국소재발이 유일한 재발이었고 134명은 국소재발을 포함하고 있었다. 생존율에 대한 예후인자에 대한 단변량분석에서 병기, T-병기, N-병기, 운동수행능력, 병소의 크기 및 치료의 목적이 통계학적으로 유의한 인자였으나, 다변량분석에서는 N-병기와 병소의 크기만이 통계학적으로 유의한 인자였다. 결론 : 식도암 환자를 방사선치료 후 장기 추적관찰한 결과 10.2$\%$의 5년 생존율 및 5.3$\%$의 10면 생존율을 얻을 수 있었다. 다변량분석의 결과 N-병기 및 병소의 크기가 유의한 예후인자였다.

• Childhood Kidney Diseases
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• 제14권1호
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• pp.42-50
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• 2010

목 적 : 단일신을 가진 소아의 임상적 특징과 동반기형 및 장기적 신기능 등에 대해 알아보고자 하였다. 방 법 : 1989년 12월부터 2009년 12월까지 20년간 서울대학교 어린이병원에서 진단된 38예의 단일신 환자를 대상으로 후향적 조사를 하였으며, 단일신은 영상검사를 통해 진단된 일측성 신장 무형성으로 정의하였고, 일측성 이형성 신의 퇴행으로 발생한 단일신은 제외하였다. 결 과 : 진단 연령의 중앙값은 6.5개월(출생직후-13세)이었고, 남자가 12명(31.6%), 여자가 26명(68.4%) 이었다. 19예(50.0%)에서는 좌측 신장이 없었고 19예에서는 우측 신장이 없었다. 산전 초음파에서 진단된 경우가 14예(36.8%), 신장 혹은 요로계 질환에 대한 검사 도중 13예(34.2%), 우연히 발견된 경우가 10예(26.3%)이었다. 동반 기형으로는 방광요관 역류 11예(28.9%)를 포함한 신장기형이 17예(44.7%), 기타 비뇨생식기계의 기형이 16예(42.1%) 그리고 다 기관 증후군 혹은 염색체 이상이 9예(23.7%)에서 진단되었다. 혈청 크레아티닌의 중간값은 0.6 mg/dL이었으며 만성 신부전이 2예(5.3%)에서 확인되었다. 결 론 : 단일신은 신장의 선천성 기형 중 상대적으로 흔한 질환이며, 일반적으로 증상이 없다. 그러나 일부에서는 단일신은 다른 기관의 이상과 연관이 되어있거나 관련된 증상이 발생한다. 단일신을 가진 소아의 연관 기형의 조기 발견과 추적 관찰이 장기적인 신 손상의 위험을 감소시키기 위해 필요하다.

• 핵의학기술
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• 제21권1호
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• pp.15-22
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• 2017

본원에서 시행하는 Brain SPECT 검사는 $^{99m}Tc-ECD$ 또는 $^{99m}Tc-HMPAO$를 주사 한 후 뇌 영상을 얻어 뇌 관류상태를 평가하는 검사이다. 하지만 검사 중 일부 환자 상태가 불안정할 경우 움직임이 발생하여 재촬영이나 검사실패로 이어지는 경우가 발생 된다. 이에 현재의 Step and Shoot Mode(SSM)이 아닌 움직임이 발생되더라도 재구성을 통해 영상 구현이 가능한 Dynamic Continuous Mode(DCM)를 적용하여 환자의 재촬영과 피폭선량을 감소시키고 검사실에 운영 효율성을 높이고자함에 있다. Deluxe PET/SPECT Phantom과 Hoffman 3D Brain Phantom으로 Filtered Back Projection(FBJ)과 Iterated Reconstruction(IR)으로 재구성하여 영상을 구현하였다. 이미지를 가지고 핵의학과 5년이상의 임상경력이 있는 의사 5명과 방사선사 5명을 대상으로 리커트 5점 척도(Likert 5 Scale)와 블라인드 판독 테스트를 실시 하였다. 판독의 블라인드 테스트 결과 최소 DCM 3Repeat (30%)에서 7Repeat (50%)까지 판독에 영향을 주지 않는다고 답해 주었다. DCM으로 검사 시 환자 움직임이 발생되면 불필요한 부분을 제거하여 재촬영, 재주사의 감소를 가져올 수 있고, 장비 오류 시 영상을 재구성 후 구현 할 수 있어 검사실 운영 효율도 높을 수 있을 것으로 기대된다. 또한 SPECT검사뿐 만 아니라 SPECT/CT검사 에서도 활발한 연구가 적용 될 거라 기대 되며 마지막으로 실제 환자 적용은 환자 데이터의 충분한 수집 후 병원 판독 실정에 맞게 도입이 필요 하리라 사료된다.

• 대한유전성대사질환학회지
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• 제18권3호
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• pp.87-94
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• 2018

선천성 염소성 설사를 가진 환아에서 국소 분절 사구체경화증이 발생하여 말기 신장병으로 발전한 사례를 보고 하고자 한다. 20세 여자 환자로, 본원에서 출생 전 산전진단에서 양수과다 및 초음파 소견으로 선천성 염소성 설사가 의심되었으며, 출생 직후 확진 되어 신생아기 때부터 KCl 보충을 통하여 증상 조절을 시작하였다. 환아는 이후 특별한 건강의 문제가 없었으나 12세에 단백뇨가 관찰되었고, 16세때 본원에서 국소분절 사구체경과증 과 2기 만성신장병 진단을 받았다. 이후 보존적 치료를 하였으며, 지속적인 단백뇨에 대한 재 평가를 위하여 입원하게 되었다. 입원 후 확인된 검사에서 사구체여과율(GFR)은 4기 신장병으로 악화되어 있었으며 신생검에서도 국소분절 사구체신염으로 인한 만성 신장병이 재 확인 되었다. 환아 및 가족을 대상으로 시행한 유전자 검사(diagnostic exome sequencing)에서는 SLC26A3 유전자의(c.2063-1G>T) 동형 접합체 변이가 각각 부모에서 전달된 것을 확인하였다. 선천성 염소성 설사 환자는 적절한 전해질 보충에도 불구하고 신기능 손상이 되기 쉬운 경향이 있으며, 따라서 조기 진단 및 충분한 전해질 보충이 이루어지는 경우에서도 환자의 신장 기능에 대한 정기적 관찰 및 적절한 보조 치료가 필요할 것으로 사료된다.

• 대한정형외과학회지
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• 제56권1호
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• pp.34-41
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• 2021

목적: 70세 이상 고령의 환자에서 시행한 슬관절 단일구획치환술의 장기 임상 결과와 합병증 및 치환물의 장기 생존율 등을 알아보고자 했다. 대상 및 방법: 2002년 3월부터 2004년 2월까지 70세 이상의 고령 환자에서 가동형 치환물을 사용하여 내측 슬관절 단일구획치환술을 시행하고 10년 이상 경과한 39명, 46예를 대상으로 장기 추시 결과를 평가했다. 수술 시 환자의 평균 연령은 74.0세였으며 수술 전 진단은 모두 퇴행성 관절염이었다. 결과: 총 46예 중 치환물의 실패로 인한 재수술이 4예 발생했고, 사망 14예 및 추시 소실 6예를 제외한 22예에서 수술 후 10년 이상 추시가 가능했다. 평균 13.1년 추시상 슬관절 점수는 수술 전 평균 53.0점에서 최종 추시 시 89.4점으로 유의미하게 향상되었고(p<0.001), 슬관절 기능 점수도 수술 전 평균 52.5점에서 최종 추시 시 80.9점으로 유의미하게 향상되었다(p<0.001). 슬관절 운동 범위는 수술 전 평균 128.8°에서 최종 추시시 132.5°로 회복되었으며 대퇴경골각은 수술 전 외반 0.1°에서 외반 5.9°로 변화했다. 수술 후 합병증으로 인한 실패는 총 4예에서 발생했으며 그중 가장 많이 발생한 합병증은 가동성 삽입물의 탈구(2예)였고 외측 구획의 관절염 및 폴리에틸렌 삽입물의 마모로 인한 실패가 각각 1예였다. 치환물의 10년 누적 생존율은 95.0%, 15년 누적 생존율은 85.7%였으며 추시 소실된 6예를 제외한 40예중 36예(90.0%)에서 재수술 없이 사망할 때까지 사용했거나 최종 추시 때까지 사용하고 있었다. 결론: 70세 이상의 고령 환자에서 시행한 슬관절 단일구획치환술은 장기 추시상 우수한 슬관절의 기능과 만족할만한 치환물의 장기 생존율을 보여주었다. 따라서 슬관절 단일구획치환술은 70세 이상 고령 환자에서도 퇴행성 슬관절염의 치료에 유용한 방법이 될 수 있을 것이다.

• 대한정형외과학회지
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• 제54권5호
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• pp.427-434
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• 2019

목적: 본 연구의 목적은 단일 술자가 시행한 슬관절 부분 치환술의 장기 임상적, 방사선적 결과 및 생존율을 분석하는 것이다. 또한 치환물의 생존에 영향을 미치는 인자를 분석하고 그에 따른 생존 곡선을 비교하는 것이다. 대상 및 방법: 1982년 12월부터 1996년 1월까지 시행된 슬관절 부분 치환술 99예를 대상으로 하였다. Modular II 10예, Microloc 44예, Allegretto 45예였다. 평균 추시기간은 16.5년이었다. 임상적 평가로 술 전, 술 후 1년, 최종 추시 hospital for special surgery(HSS) 점수와 관절운동범위를 조사하였다. 방사선적 평가로 술 전, 술 후 2주, 최종 추시 대퇴 경골각을 조사하였다. Kaplan-Meier 생존 분석을 이용하여 생존율을 분석하였다. Cox 비례위험모형을 이용하여 나이, 성별, 체질량 지수, 술 전 진단, 치환물의 종류 중 생존에 영향을 미치는 요인을 조사하였다. 생존에 영향을 미치는 인자에 따라 군을 나누어 생존 곡선을 비교하였다. 결과: 전체 HSS 점수는 평균 술 전 57.7점, 술 후 1년 92.7점, 최종 추시 79.1점이었다(p<0.001). 관절운동범위는 평균 술 전 134.3도, 술 후 1년 138.4도, 최종 추시 129.3도였다(p<0.001). 전체 대퇴 경골각은 평균 술 전 내반 0.8도, 술 후 2주 외반 4.1도, 최종 추시 외반 3.0도였다(p=0.003). 전체 생존율은 5년 91.8%, 10년 82.9%, 15년 71.0%, 20년 67.0%였다. 부분 치환술의 생존에 영향을 미치는 요인은 환자의 나이와 치환물의 종류였다. 나이가 높을수록 실패 위험이 낮았으며(hazard ratio=0.933), Microloc 사용 시 Modular II와 Allegretto에 비해 위험률이 높았다(hazard ratio=0.202, 0.430, respectively) 60세 미만군의 생존 곡선이 60세 이상 군에 비해 의미 있게 낮았다(p=0.003). Microloc 사용군의 생존 곡선이 Modular II와 Allegretto 사용군에 비해 낮았다(p=0.025). 결론: 고정형 치환물을 사용한 슬관절 부분 치환술의 장기 임상적, 방사선적 결과 및 생존율은 만족스러웠다. 부분 치환물의 장기 생존을 위해 적절한 환자와 치환물의 선택이 중요할 것이다.

• 대한정형외과학회지
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• 제54권1호
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• pp.37-44
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• 2019

목적: 슬관절 주위 악성 골연부 종양 치료 시 종양의 도약전이나 슬관절 내 침범, 종양인공관절 치환술 후 반복적 감염 치료를 위한 인접골 절제, 국소재발 및 기계적 파괴가 발생한 경우 슬관절 상하부 전치환술은 하지와 슬관절 기능을 보존하는 한 방법이다. 이 중 반복된 감염 치료를 위해 슬관절면 반대측 골까지 절제 후 한시적 슬관절 고정술을 한 환자에서 가동관절로 재치환술 시 적응증, 합병증, 치환물의 생존율에 대하여 알아보고자 하였다. 대상 및 방법: 본 연구는 슬관절 상하부 전치환술 환자 34예 중 슬관절 주위 종양인공관절 치환술 후 반복적인 감염으로 슬관절면 반대측 골까지 절제한 후 한시적 슬관절 고정술이 불가피했던 13예를 대상으로 하였다. 진단, 원발병소의 위치, 슬관절 상하부 전치 환술을 받기 전까지 수술 횟수 및 기간, 재 재건술 후 치환물의 생존율, 합병증, 기능적 결과를 분석하였다. 결과: 슬관절 상하부 종양인공관절 치환물의 Kaplan-Meier 법에 의한 5, 10년 생존율은 각각 69.0%±12.8%, 46.0%±20.7%였다. 총 13예 중 6예(46.2%)에서 주 합병증이 발생하여 3예는 내고정물을 제거 후 슬관절 고정술을, 2예는 내고정물의 부분교체를, 나머지 1예는 감염된 육아조직만 제거하였다. 최종 추시상 가동관절을 유지한 10예의 Musculoskeletal Tumor Society 기능평가 점수는 평균 24.6점(21-27점)이었다. 슬관절 상하부 종양인공관절 치환술이 실패하여 슬관절 고정술로 재치환 한 3예의 기능평가 평균 점수는 12.3점(12-13점)이었다. 가동관절을 유지한 10예의 슬관절 가동 범위는 평균 67°였다(0°-100°). 슬관절 능동적 신전제한은 평균 48° (20°-80°)였다. 결론: 슬관절 주위 종양인공 치환술 후 반복적인 감염으로 슬관절면 반대측 골까지 절제 후 한시적 슬관절 고정술이 불가피했던 환자에서 슬관절 상하부 종양인공관절 치환술은 합병증의 위험성은 높으나 슬관절 고정술에 비해 기능적 결과가 월등하므로 시도할 가치가 있는 술식이다. 고정된 슬관절을 가동관절로 치환 시 반흔 조직을 철저히 제거하고 연부조직을 확보하여 종양인공관절을 삽입 후 굴곡 및 신전이 가능할 정도의 공간을 확보하는 것이 술식의 성공에 중요하다고 생각된다.

• 대한의용생체공학회:의공학회지
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• 제6권2호
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• pp.1-8
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• 1985

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70$\pm$1.32mmHg/min)compared to CF dialyzers(4.32$\pm$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500, 550, 570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500, 550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100, 300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3, 000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x In this paper, we describe the design methodology and specifications of the developed module-based bedside monitors for patient monitoring. The bedside monitor consists of a main unit and module cases with various parameter modules. The main unit includes a 12.1" TFT color LCD, a main CPU board, and peripherals such as a module controller, Ethernet LAN card, video card, rotate/push button controller, etc. The main unit can connect at maximum three module cases each of which can accommodate up to 7 parameter modules. They include the modules for electrocardiograph, respiration, invasive blood pressure, noninvasive blood pressure, temperature, and SpO2 with Plethysmograph.SpO2 with Plethysmograph.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1993년도 한국우주과학회보 제2권2호
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• pp.17-17
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• 1993

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70${\pm}$1.32mmHg/min)compared to CF dialyzers(4.32${\pm}$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500,550,570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500,550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100,300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3,000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x In this paper, we describe the design methodology and specifications of the developed module-based bedside monitors for patient monitoring. The bedside monitor consists of a main unit and module cases with various parameter modules. The main unit includes a 12.1" TFT color LCD, a main CPU board, and peripherals such as a module controller, Ethernet LAN card, video card, rotate/push button controller, etc. The main unit can connect at maximum three module cases each of which can accommodate up to 7 parameter modules. They include the modules for electrocardiograph, respiration, invasive blood pressure, noninvasive blood pressure, temperature, and SpO2 with Plethysmograph.