선형가속기를 이용한 뇌수막종의 뇌정위적 방사선수술

류경식,손병철,김문찬,서태석,계철승,윤세철,강준기,Ryu, Kyung-Sik,Son, Byung-Chul,Kim, Moon-Chan,Suh, Tae-Suk,Kay, Chul-Seung,Yoon, Sei-Chul,Kang, Joon-Ki 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.3

Objective : To evaluate the role of stereotactic LINAC radiosurgery in treatment of meningiomas, the authors retrospectively analyzed the result of radiosurgery in our institute. Method: During last ten years, twenty patients underwent stereotactic LINAC radiosurgery(LINAC SRS) for meningiomas. The mean age of the patients was 51 years(22-78 years). The most common tumor location for radiosurgery was parasagittal, sphenoid wing and tentorial area. With regards to indications of radiosurgery for meningiomas, LINAC radiosurgery was done for primary treatment in six patients, for postoperative residual tumors in eleven patients, for postoperative regrowth in three patients. Mean tumor volume was $5.14cm^3$($0.28-15.1cm^3$), mean field diameter was 2.01cm(1.2-3cm). The mean marginal dose was 20.55Gy(13-30Gy). The follow-up evaluation was done annually with radiologic findings and clinical status. The mean follow-up period was 46.8(24-120) months. Result : In the radiologic response, the tumor volume was reduced in five(25%) of twenty patients, fourteen showed arrested growth(70%), but one patient showed increased growth(5%). In the clinical response, nine patients improved clinically(45%), ten patients was stable(50%) and one patient worsened during follow-up period. With regards to correlation with radiologic and clinical response, in nineteen patients who showed radiologic response to radiosurgery(decreased and arrested growth after radiosurgery), nine patients(47.4%) improved and ten patients (52.6%) showed no change, one patient(5%) had symptomatic radiation necrosis at four years after SRS, which needed craniotomy. Conclusion : The overall control rate of meningiomas with LINAC radiosurgery was 95% in radiologic follow up and 95% clinically. The radiation complication rate was 5%. These results indicate that LINAC radiosurgery can be considered as safe and effective method for meningiomas.

Gamma 및 비Gamma군 분포모형에 의한 강우의 지점 및 지역빈도 비교분석 (I)

류경식,이순혁,Ryoo, Kyong-Sik,Lee, Soon-Hyuk 한국농공학회 2004 한국농공학회논문집 Vol.46 No.4

This study was conducted to derive the design rainfall by the consecutive duration using the at-site frequency analysis. Using the errors, K-S tests and LH-moment ratios, Log Pearson type 3 (LP3) and Generalized Extreme Value (GEV) distributions of Gamma and Non-Gamma Family, respectively were identified as the optimal probability distributions among applied distributions. Parameters of GEV and LP3 distributions were estimated by the method of L and LH-moments and the Indirect method of moments respectively. Design rainfalls following the consecutive duration were derived by at-site frequency analysis using the observed and simulated data resulted from Monte Carlo techniques. Relative root-mean-square error (RRMSE) and relative efficiency (RE) in RRMSE for the design rainfall derived by at-site analysis in the observed and simulated data were computed and compared. It has shown that at-site frequency analysis by GEV distribution using L-moments is confirmed as more reliable than that of GEV and LP3 distributions using LH-moments and Indirect method of moments in view of relative efficiency.

지점 및 지역빈도분석에 의한 설계강우량의 추정

류경식,이순혁,맹승진 한국수자원학회 2004 한국수자원학회 학술대회 Vol.2004 No.1

노령기 골다공증성 흉요추 방출성 압박 골절에서 수술 중 척추성형술을 이용한 후방 경유 수술법

류경식,박춘근 대한신경외과학회 2003 Journal of Korean neurosurgical society Vol.33 No.3

Objective:Treatments of osteoporotic bursting vertebral body fracture(OBF) of thoracic and lumbar spines have been limited to conservative managements especially in the elderly patients. The authors correct kyphosis and stabilize the spine by the posterior approach with intraoperative polymethylmethacrylate(PMMA) vertebroplasty. Methods:From March 1999 to June 2000, eight patients with OBF underwent posterior approach with intraoperative vertebroplasty. The patients included 7 women and 1 man aged 54-82 year. Average T-score on bone marrow density was -3.02. In the case of old fracture with sclerosis in the posterior wall, after laminectomy, the retropulsed posterior wall of the fractured spine was reduced with L-shaped micro-bone impactor through the lateral epidural spaces, in prone position. About 6cc of PMMA was injected into the fractured vertebral body via transpedicular route, and then, small amount of PMMA was also injected into each entry point of the screws. All patients underwent one above and one below short segment fixation followed by correction of kyphotic deformity. Results:The preoperative clinical symptoms improved gradually in all patients. During postoperative follow-up for more than 7 months, there was no recurrence of the preoperative clinical symptoms, aggravation of kyphosis or instrumentation failure. Conclusions:It is suggested that posterior approach with short segment fixation and intraoperative PMMA vertebroplasty could be a new surgical modality for osteoporotic bursting fracture of the thoracic and lumbar spines especially in the aged. Key words:Osteoporosis;Bursting fracture;Short segment fixation;Vertebroplasty.

유역 물관리 차원에서의 용수량 적용방안

류경식 한국농공학회 2006 韓國農工學會誌 : 전원과 자원 Vol.48 No.2

수리시설물별 관개면적을 고려한 유출변화특성분석

류경식,이상진 한국수자원학회 2008 한국수자원학회논문집 Vol.41 No.6

본 연구는 소규모 수리시설물이 장기유출에 끼치는 영향에 대해 시 공간적으로 상세히 분석하고, 분석된 결과를 토대로 장기유출 모의모형에 소규모 수리시설물의 영향을 반영할 수 있도록 구성함으로서 유역의 장기유출 모의결과의 신뢰도를 증진시키는 것이 목적이다. 따라서 본 연구에서는 대상유역의 소규모 수리시설물 현황을 파악하고 각 수리시설물별로 하천유량에 끼치는 영향을 분석한 후, 수리시설물의 영향을 고려할 수 있도록 강우-유출 모형을 구축하였다. 수리시설물에 This study was conducted to promote reliability of the simulated result for the long-term streamflow in Daecheong watershed. This system was constructed by the SSARR model that considered the effect of small scale irrigation facilities. We investigated th

Non-OS 임베디드 시스템에서 개선된 알고리즘을 적용한 요구 페이징 기법

류경식,전창규,김용득,Lew, Kyeung Seek,Jeon, Chang Kyu,Kim, Yong Deak 대한임베디드공학회 2010 대한임베디드공학회논문지 Vol.5 No.4

In this paper, we try to improve the performance of the demand paging loader suggested to use the demand paging way that is not based on operating system. The demand paging switching strategy used in the existing operating system can know the recently used pages by running multi-processing. Then, based on it, some page switching strategies have been made for the recently used pages or the frequently demanded pages. However, the strategies based on operating system cannot be applied in single processing that is not based on operating system because any context switching never occur on the single processing. So, this paper is trying to suggest the demand paging switching strategies that can be applied in paging loader running in single process. In the Return-Prediction-Algorithm, we saw the improved performance in the program that the function call occurred frequently in a long distance. And then, in the Most-Frequently-Used-Page-Remain-Algorithm, we saw the improved performance in the program that the references frequently occurred for the particular pages. Likewise, it had an enormous effect on keeping the memory reduction performance by the demand paging and reducing the running time delay at the same time.

관측년수변화에 따른 설계강우량의 변동추이

류경식,황만하,고익환 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

만성 추간판인성 요통 환자에서 추간판내 열 치료법의 치료효과 ; 예비보고

류경식,박춘근,Ryu, Kyung Sik,Park, Chun Kun 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.6

Objective : The IDET(Intradiscal electrothermal therapy) appears as a new therapeutic modality for intractable discogenic back pain. We carried out a prospective study to analyze and evaluate the therapeutic effects of IDET. Methods & Results : During a six month period, we performed IDET in 39 patients with chronic low back pain using RITA Model 30 Electrosurgical device. The patients included 21 men and 18 women. The mean patient age was 50.2 years(range 21-73 years). All patients underwent preoperative plain radiography and MRI for excluding non-discogenic back pain. We conducted discography-CT to reveal painful discs in all patients. During the study, we measured intradiscal pressure subjectively. The area of annular tear, which identified with post-discography CT scan, was coagulated in $90^{\circ}C$ of temperature for 15 minutes. Of the 17 patients who were followed up more than three months after surgery, the 10 patients(58.8%) experienced clinical improvement. Three patients had high intradiscal pressure on discography, other three patients had loss of disc height more than 30% of normal on plain radiography, and one patient suffered from postoperative epidural abscess. All of these patients were included in the remaining no improvement group(41.2%). Conclusion : The IDET procedure could be an alternative modality for discogenic back pain. It appears that a patient who has low intradiscal pressure on discography and intact disc height on plain radiography is considered a good candidate for IDET.

요추부 인공추간판치환술

류경식,박춘근 대한척추신경외과학회 2009 Neurospine Vol.6 No.4

In surgical treatments of degenerative lumbar disc disease, arthrodesis is well known to be a gold standard; however various disadvantages related to elimination of the segmental motion and the procedures of fusion surgery have become a matter of concern. To this end, total disc replacement (TDR) was recently highlighted as one of alternative surgical modalities and being used widely. However, although it has been almost 10 years since lumbar TDR was int- roduced and actively used in the clinic, its clinical usefulness is still in dispute. The authors review and put together the history, biomechanics, and currently available prostheses of lumbar TDR in the present study. Some of the recent preliminary, mid-term and long-term clinical results of lumbar TDR in degenerative lumbar spine diseases are also reviewed. Lastly, we look out over the future prospect of lumbar TDR. In surgical treatments of degenerative lumbar disc disease, arthrodesis is well known to be a gold standard; however various disadvantages related to elimination of the segmental motion and the procedures of fusion surgery have become a matter of concern. To this end, total disc replacement (TDR) was recently highlighted as one of alternative surgical modalities and being used widely. However, although it has been almost 10 years since lumbar TDR was int- roduced and actively used in the clinic, its clinical usefulness is still in dispute. The authors review and put together the history, biomechanics, and currently available prostheses of lumbar TDR in the present study. Some of the recent preliminary, mid-term and long-term clinical results of lumbar TDR in degenerative lumbar spine diseases are also reviewed. Lastly, we look out over the future prospect of lumbar TDR.