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      • 뇌암 및 두경부암 체적변조방사선치료시 Jaw-Tracking 기법의 선량학적 유용성 평가

        김희성,문재희,김군주,서정민,이정진,최재훈,김성기,장인기,Kim, Hee Sung,Moon, Jae Hee,Kim, Koon Joo,Seo, Jung Min,Lee, Joung Jin,Choi, Jae Hoon,Kim, Sung Ki,Jang, In-Gi 대한방사선치료학회 2018 대한방사선치료학회지 Vol.30 No.1

        목 적 : 체적변조회전방사선치료(VMAT)는 종양의 모양에 맞게 균일하면서도 정밀한 방사선 조사를 하면서 동시에 정상조직의 방사선 손상위험을 줄이는 장점이 있어 뇌암, 두경부암 및 전립선암 등의 종양과 정상장기가 가까운 암의 치료에 사용되고 있다. 본 연구의 목적은 뇌암 및 두경부암 환자의 VMAT 방사선 치료 시 Jaw-Tracking technique(JTT)의 선량학적 유용성을 평가하고자 한다. 대상 및 방법 : 본원에서 VMAT 치료기법으로 방사선치료를 받은 뇌암 및 두경부암 환자 8명을 선택하였다. 환자의 종양 및 정상 장기의 윤곽그리기(contouring) 정보를 Velocity(Varian, USA)의 deformable registration을 이용하여 Rando phantom에 fusion하였다. Varian Eclipse(ver 15.5, Varian, USA)를 사용하여 Jaw-Tracking 사용 유무를 제외하고 환자 치료 시 사용한 beam parameter와 동일하게 치료계획을 진행하였다. 평가 지표로써 target과 OAR의 최대선량, 평균선량을 사용하여 비교하였고 치료계획 검증을 위해 Portal dosimetry를 시행하였다. 결 과 : JTT를 사용했을 경우는 Static-Jaw technique(SJT)을 사용하였을 경우보다 OAR의 상대 선량이 각각 평균선량은 5.24 %, 최대선량은 7.05 % 감소한 것으로 나타났다. 다양한 OAR에서 평균선량과 최대선량의 감소의 범위는 각각 0.01~3.16 Gy, 0.12~6.27 Gy로 나타났다. Target의 경우는 JTT의 경우가 SJT보다 GTV, CTV, PTV의 최대선량이 각각 0.17 %, 0.43 %, 0.37 % 감소하였으며, 평균선량은 0.24 %, 0.47 %, 0.47% 감소하였다. 감마분석은 3 %/3 mm, 통과율 95 % 이상을 통과 기준으로 설정하였고 JTT, SJT 통과율은 각각 $98{\pm}1.73%$, $97{\pm}1.83%$이었다. 실험에 적용된 모든 OAR의 선량을 비교해 보았을 때, JTT을 사용하였을 경우가 SJT보다 MLC 외에 추가적인 jaw 차폐로 인하여 선량이 유의미하게 줄어들었다는 것을 알 수 있었다. 결 론 : VMAT 치료계획을 이용한 방사선 치료시 뇌암, 두경부암과 같이 종양과 정상 장기가 인접한 경우와 MLC를 통한 누설선량을 증가시킬 수 있는 넓은 조사야 및 높은 에너지의 사용을 필요로 하는 방사선 치료 시 JTT를 적용함으로써 종양주변 정상조직의 피폭선량을 낮추고 이로 인해 PTV의 target coverage를 높일 수 있을 것이라 판단된다. Purpose : Volumetric Modulated Arc Therapy(VMAT) has the advantage of uniformly and precisely irradiating the tumor to the shape of the tumor while reducing the risk of radiation damage to normal tissues. such as brain cancer, head and neck cancer and prostate cancer, It is being used for treatment. The purpose of this study is to evaluate the usefulness of the Jaw-Tracking technique(JTT) in VMAT for brain and head and neck cancer. Materials and Methods : We selected eight patients with brain and head and neck cancer(4 Brain, 4 head and neck) who were treated with the VMAT treatment technique. Contouring information of the patient's tumor and normal organ was fused to the Rando phantom using the deformable registration of Velocity(Varian, USA). A treatment plan was developed using the Varian Eclipse(ver 15.5, Varian, USA) with the same patient actual beam parameters except for the use of jaw-tracking. As the evaluation index, the maximum dose and mean dose of target and OAR were compared and a portal dosimetry was performed for the treatment plan verification. Results : When using JTT, the relative dose of OAR decreased by 5.24 % and the maximum dose by 7.05 %, respectively, compared with the Static-Jaw technique(SJT). In the various OARs, the mean dose and maximum dose reduction ranges ranged from 0.01 to 3.16 Gy and from 0.12 to 6.27 Gy, respectively. In the case of the target, the maximum dose of GTV, CTV, PTV decreased by 0.17 %, 0.43 %, and 0.37 % in JTT, and the mean dose decreased by 0.24 %, 0.47 % and 0.47 %, respectively. Gamma analysis The JTT and SJT passing rates were $98{\pm}1.73%$ and $97{\pm}1.83%$ on the basis of 3 % / 3 mm, respectively. Comparing the doses of all OARs applied to the experiment, it was found that the use of JTT resulted in a significant decrease in dose due to additional jaw shielding besides MLC than SJT. Conclusion : In radiation therapy using VMAT treatment plan, we can apply JTT in the case of adjacent tumor and normal organs such as brain cancer and head and neck cancer, and in radiotherapy required large field and high energy caused increase leakage dose through MLC. It is considered that the target dose of PTV can be increased by lowering the dose of normal tissue surrounding the tumor.

      • 소아에 시행한 복강경 담낭 절제술

        김희성,남소현,김대연,김성철,김인구,Kim, Hee-Seong,Nam, So-Hyun,Kim, Dae-Yeon,Kim, Seong-Chul,Kim, In-Koo 대한소아외과학회 2006 소아외과 Vol.12 No.2

        Laparoscopic cholecystectomy has been increasingly used because of several advantages, less pain, better expectation for cosmesis (requires small incisions), and more rapid recovery compared with open cholecystectomy. Oral intake is tolerated on the day of operation or on the next. In this study, we evaluated the effectiveness and safety of laparoscopic cholecystectomy in children. Nine cases of laparoscopic cholecystectomy for acute and chronic cholecystitis in children were performed at Asan Medical Center between April 2002 and April 2004. Laparoscopic cholecystectomy was performed on a total of 10 patients, but one of them was excluded because of the simultaneous splenectomy for sickle cell anemia. Clinical presentation, operative findings, operation time, length of hospital stay, and postoperative complications were analyzed. Mean age was 10.4 (4.15) years, and only 3 of patients were less than 10 years. One patient was female. In 8 the diagnosis was calculous cholecystitis. Mild adhesions were found in 3 cases and intraoperative bile leakage in 2. There was no conversion to open surgery and there were no vascular, bowel, or bile duct injuries. Mean operation time was 82.2 (20.160) minutes; mean length of hospital stay was 2.1 (1.3) day. There was no postoperative complication. Laparoscopic cholecystectomy in children was remarkably free of side effects and complications and had a short recovery time. Laparoscopic cholecystectomy for cholecystitis is considered to be a standard procedure in children.

      • KCI등재

        운용시험을 통한 KASS 성능 분석

        김희성,손민혁,이병석,이백준,Heesung Kim,Minhyuk Son,ByungSeok Lee,Baeckjun Yi 항법시스템학회 2024 Journal of Positioning, Navigation, and Timing Vol.13 No.2

        The Korea Augmentation Satellite System (KASS) has been certified by the Ministry of Land, Infrastructure and Transport (MOLIT) and commenced Safety-of-Life (SoL) service at the end of 2023. KASS complies with the APV-I signal-in-space performance requirements defined in the International Civil Aviation Organization (ICAO) Standards and Recommendation Practices (SARPs). The performance of KASS is verified through two steps. In the first step, design conformity from the aspect of performance is verified by both review and analysis of design and simulation. In the second step, operational conformity is tested and assessed by operational testing using real data and a deployed system with operational SWs and configurations. This paper presents a methodology, a procedure and results for the KASS operational testing. Finally, performance degradation events and results by month and region during the operational testing are presented and analyzed.

      • KCI등재

        고혈압을 동반한 당뇨병에서 유병기간에 따른 뇌졸중 위험도

        김희성,Kim, Hee Sung 대한임상검사과학회 2020 대한임상검사과학회지(KJCLS) Vol.52 No.3

        Stroke is a major cause of death and disorder, and diabetes mellitus (DM) is a significant risk factor of stroke. This study examined the importance of target blood pressure (<140/<90 mmHg) management in patients with DM. Based on the data of the 6th National Health and Nutrition Examination Survey, a total of 16,389 patients aged 18 to under 80 were assessed through regression analysis to estimate the risk of stroke through blood pressure control. The prevalence of stroke according to the presence or absence of DM was higher in the diabetic group, and a longer duration of DM indicated a higher risk of hypertension and stroke. The hazard ratio of stroke was lower in the maintenance group (0.57) of target blood pressure (<140/<90 mmHg) compared to the high blood pressure group(>140/>90 mmHg). Despite the accompanying treatment for DM and hypertension, the frequency of hypertension increased, and the prevalence of stroke increased after five years of DM. Hence, effective blood pressure management at this time is important. The risk of stroke should be reduced by continuously managing blood pressure in DM. 뇌졸중은 사망발생 및 장애를 일으키는 주요 원인 질환이며, 당뇨병은 뇌졸중의 주요 위험인자이다. 당뇨병 환자가운데 뇌졸중을 동반한 환자에서 적정 혈압 관리의 중요성을 알아보고자 한다. 제6기 국민건강영양조사 자료를 바탕으로 18세 이상 80세 미만자 총 16,389명을 대상으로 회귀분석을 통하여 당뇨병 유병기간에 따른 혈압조절을 통한 뇌졸중의 위험도를 산정하였다. 당뇨병 유무에 따른 뇌졸중의 유병률은 당뇨병 환자 군에서 높았고, 당뇨병의 유병기간이 길어질수록 고혈압과 뇌졸중의 위험도는 상승하였으며, 당뇨병과 고혈압에 대한 치료 비율은 높았다. 고혈압군에 비해 적정 혈압 유지군(<140/<90 mmHg)에서 뇌졸중 위험비(HR)는 0.57 낮았다. 당뇨병과 고혈압에 대한 치료가 동반됨에도 불구하고 고혈압의 빈도는 상승하였고, 당뇨병 유병기간 5년 이후 뇌졸중의 유병률이 상승함에 따라 이 시기의 효과적인 혈압관리가 더욱 중요하다. 당뇨병 환자에서 지속적으로 적정 혈압으로 관리함으로써 뇌졸중 위험도를 낮추는 것이 중요하다.

      • 강도수준을 고려한 원주형 공시체에 대한 콘크리트 압축강도의 크기효과

        김희성,진치섭,어석홍,Kim, Hee-Sung,Jin, Chi-Sub,Eo, Seok-Hong 한국콘크리트학회 1999 콘크리트학회지 Vol.11 No.2

        콘크리트 원주형 공시체의 크기에 따른 압축강도의 감소현상은 많은 관심을 받아 왔으나, 지금까지도 이에 대해 제시된 모델식이 드문 실정이다. 기존의 연구결과에 의하면 콘크리트의 강도는 부재의 크기가 증가할수록 감소하며 그 파괴거동을 규명하기 위해서는 비선형 파괴역학 이론을 적용해야 함을 알 수 있다. 표준형 및 비표준형 공시체의 크기에 따른 압축강도의 변화를 파괴역학 이론에 따라 연구하고 실용적인 예측 모델식이 제시된 바 있지만 콘크리트의 강도수준에 따른 파괴메카니즘의 차이를 고려한 관계식은 전무한 상황이다. 따라서, 본 논문에서는 공시체의 크기와 h/d의 영향 및 콘크리트 압축강도수준을 고려하여 보다 일반화된 압축강도 예측 모델식을 제시한다. The reduction phenomena of concrete compressive strength with the size of specimens have been extensively investigated, but till now the adequate analysis technique is not fixed. The existing research results show that the bigger the member size, the smaller the strength. This means the nonlinear fracture mechanics theory is needed in order to analyze the fracture behaviors of concrete and the size effect. There is a few model equations that is to predict the size effect of compressive strength of standard and non-standard cylindrical specimen. However, theses equations did not considered the difference of fracturing mechanism which depends on the strength level. In this paper, model equations to predict compressive strength of concrete considering the size effect and strength level are suggested. The size effect model suggested in this paper shows good prediction compared with the existing test data of various concrete size and strength level.

      • SCOPUSKCI등재

        최근 일반 건강인에 대한 매독 혈청 검사 양성율 - 1995년

        김희성,이한승,이민걸,이정복 ( Hee Sung Kim,Han Sung Lee,Min Geol Lee,Jung Bock Lee ) 대한피부과학회 1997 大韓皮膚科學會誌 Vol.35 No.3

        Background: The VDRL is used as a screening test for syphilis worldwide. In addition, reactive rates of the VDRL test are used to estimate the incidence of syphilis. The prevalence of syphilis reported in Korea varies according to the study population, district and time. Reports on prevalence of syphilis indicate that reactive rates of the serologic test for syphilis showed an increasing tendency in the 1960s and has steadily decreased in the 1990s. We have already reported VDRL positive rates periodically since the late 1970s in similar areas with similar population groups and methods in order to standardize the results for accurate analysis of the prevalence of syphilis in Korea. Objective : This study was performed utilizing the VDRL test in order to find out if the decreasing trend of syphilis prevalence is still continuing. Methods : The ser ologic tests for syphilis were carried out on 13,426 apparently normal adults aged twenty-years-old or over(8,250 blood donors in the Seoul area, 2,461 physical examinees examined at Severance Hospital, Yonsei University and 2,715 pregnant women at delivery at Severance Hospital, Yonsei University ) from January to December 1995. We hve performed the VDRL quantitative test in VDRL-reactive persons among blood donors and pregnant women. Results : The reactive rate of the serum VDRL test was 0.2% in 13,426 healthy adults(blood donors.0.2%, physical examinees:0,2%, pregnant women:0.3%). There was a statistically decreasing tendency compared to 0.4% in 1990(p<0.001). The VDRL quantitative test resulted in levels below the 1:2 titer in 92% of the VDRL-reactive physical exarninees and pregnant women. Conclusion . From the comparison of VDRL reactive rates for syphilis in an apparently normal Korean population obtained by the present author group since 1977, i.e., 2.5% in 1977, 1.1% in 1981, 0.6% in 1986, 0.4% in 1990 and 0.2% in 1995, it is clear that the prevalence of syphilis has been rapidly decreasing since the mid 1970s in Korea. (Kor J Dermatol 1997;35(3): 514-519)

      • 구절 동사와 전치사 수반동사의 의미에 따른 음성적 실현

        김희성,송지연,김기호,Kim, Hee-Sung,Song, Ji-Yeon,Kim, Kee-Ho 대한음성학회 2007 말소리 Vol.63 No.-

        Verb phrase could have two different meanings according to which is followed after verb; adverb or preposition. The meaning of 'verb+adverb' is deduced from a figurative meaning which is idiomatic expression, and 'verb+preposition' is interpreted as the literal meaning. The purpose of this study is to observe how English native speakers and Korean leaners of English distinguish two sentences of the same word strings with acoustic cues like pause and duration. According to the result, as pause was used for meaning distinction, it was likely that the pause length preceding prepositions was longer than that of following adverbs. To distinguish two sentences of the same word strings, all participants seemed to use pause, verb lengthening and adverb/preposition lengthening. Among them, there is a hierarchical significance; in sequence, pause, verb lengthening, adverb/preposition lengthening.

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