• Radiation Oncology Journal
• /
• 제17권2호
• /
• pp.136-140
• /
• 1999

목적: 전립선특이항원(prostate specific antigen, PSA)은 전립선암의 진단, 수술이나 방사선치료 후 결과 판정 및 추적관찰 등에 널리 사용된다. 근치적방사선치료를 시행한 전립선암 환자에 있어 혈중 PSA 농도가 감소되는 양상 및 이에 영향을 미치는 인자 등에 대한 고찰을 통하여, 환자의 방사선치료 후 결과 판정 및 추적관찰 시 PSA 를 이용한 경과 판정에 필요한 자료를 마련하고자 후향적 분석을 시행하였다. 대상 및 방법 : 1993년 4월부터 1998년 5월까지 서울대학교병원 치료방사선과에서 근치적방사선치료를 받은 전립선암 환자로, 호르몬치료나 항암화학요법을 시행 받지 않은 20명을 대상으로 하였다. 방사선치료는 전골반에 45 내지 50Gy 조사 후 축소조사야로 14 내지 20Gv를 추가하여, 전립선에 총 63 내지 70Gy를 조사하였다. 추적관찰기간은 13개월 내지 66개월로 중앙값은 26개월이었다. 방사선치료 후 혈중 PSA 농도의 정상화 기준은 3.0ng/ml 미만으로 하였다. 결과 : 혈중 PSA의 농도는 방사선치료 후 서서히 감소하는 경향을 보였으며, 반감기는 0.6 내지 4.0개월로 평균 2.1(${\pm}$0.9)개월, 중앙치는 1.9개월이었다. 20명의 환자 중 19명(95%)에서 PSA 농도가 정상 범위에 도달하였고, 정상범위에 도달하는데 소요된 기간은 방사선치료 종료 직후 내지 12개월로 평균 5.3(${\pm}$2.7)개월, 중앙치는 5.0개월이었다. 방사선치료 전의 PSA 농도가 10ng/ml 미만이었던 8명 중 2명에서 방사선치료 종료 시 PSA 농도가 정상화되었고, 10ng/m1 이상이었던 12명에서는 치료 종료 시까지 정상화되지 않았다. PSA 농도가 정상화된 19명의 환자에서 근치적방사선치료 후 혈중 최저 PSA 농도(nadir PSA)는 0.2 내지 1.8ng/ml로 평균 0.8(${\pm}$0.5)ng/ml, 중앙치는 0.6ng/ml 였다. 최저 PSA 농도에 도달하는데 소요되는 기간은 6 내지 23개월로 평균 13.5(${\pm}$4.3)개월, 중앙치 14.0개월이었다. 치료 후 추적관찰 중 2명에서 PSA 농도가 임상적 재발 진단 6개월 및 20개월 전에 증가되었다. 결론 : 혈중 PSA 농도가 방사선치료 후 12개월 이내에 정상화되지 않는 경우 전립선내의 잔류암이나 원격전이를 의심할 수 있으며, 치료 후 추적 관찰 시 재발의 조기진단에 유용하다는 것을 알 수 있었다.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1234-1245
• /
• 2018

The risk of multi-unit nuclear power plants (NPPs) at a site has received considerable critical attention recently. However, current probabilistic safety assessment (PSA) procedures and computer code do not support multi-unit PSA because the traditional PSA structure is mostly used for the quantification of single-unit NPP risk. In this study, the main purpose is to develop a multi-unit Level 2 PSA method and apply it to full-power operating six-unit OPR1000. Multi-unit Level 2 PSA method consists of three steps: (1) development of single-unit Level 2 PSA; (2) extracting the mapping data from plant damage state to source term category; and (3) combining multi-unit Level 1 PSA results and mapping fractions. By applying developed multi-unit Level 2 PSA method into six-unit OPR1000, site containment failure probabilities in case of loss of ultimate heat sink, loss of off-site power, tsunami, and seismic event were quantified.

• Nuclear Engineering and Technology
• /
• 제34권4호
• /
• pp.331-343
• /
• 2002

We performed an importance analysis of In-Service Testing (157) components for Ulchin Unit 3 using the integrated evaluation method for categorizing component safety significance developed in this study. The developed method is basically aimed at having a PSA expert perform an importance analysis using PSA and its related information. The importance analysis using the developed method is initiated by ranking the component importance using quantitative PSA information. The importance analysis of the IST components not modeled in the PSA is performed through the engineering judgment, based on the expertise of PSA, and the quantitative and qualitative information for the 157 components. The PSA scope for importance analysis includes not only Level 1 and 2 internal PSA but also Level 1 external and shutdown/low power operation PSA. The importance analysis results of valves show that 167 (26.55%) of the 629 IST valves are HSSCs and 462 (73.45%) are LSSCs. Those of pumps also show that 28 (70%)of the 40157 pumps are HSSCs and 12 (30%) are LSSCs.

• Nuclear Engineering and Technology
• /
• 제52권5호
• /
• pp.975-983
• /
• 2020

Since the Fukushima Daiichi accident in 2011, concerns for the safety of multi-unit Nuclear Power Plant (NPP) sites have risen. This is because more than 70% of NPP sites are multi-unit sites that have two or more NPP units and a multi-unit accident occurred for the first time. After this accident, Probability Safety Assessment (PSA) has been considered in many countries as one of the tools to quantitatively assess the safety for multi-unit NPP sites. One of the biggest concerns for a multi-unit accident such as Fukushima is that the consequences (health and economic) will be significantly higher than in the case of a single-unit accident. However, many studies on multi-unit PSA have focused on Level 1 & 2 PSA, and there are many challenges in terms of public acceptance due to various speculations without an engineering background. In this study, two kinds of multi-unit Level 3 PSA for multi-unit site have been carried out. The first case was the estimation of multi-unit risk with conservative assumptions to investigate the margin between multi-unit risk and QHO, and the other was to identify the effect of time delays in releases between NPP units on the same site. Through these two kinds of assessments, we aimed at investigating the level of multi-unit risk and understanding the characteristics of risk in a multiunit context.

• Nuclear Engineering and Technology
• /
• 제30권1호
• /
• pp.58-74
• /
• 1998

A PC window-based computer code, CONPAS (CONtainment Performance Analysis System), has been developed to integrate the numerical, graphical, and results-operation aspects of Level 2 probabilistic safety assessments (PSA) for nuclear power plants automatically. As a main logic for accident progression analysis, it employs a concept of the small containment phenomenological event tree (CPET) helpful to trace out visually individual accident progressions and of the detailed supporting event tree (DSET) for its detailed quantification. For the integrated analysis of Level 2 PSA, the code utilizes five distinct, but closely related modules. Its computational feasibility to real PSAs has been assessed through an application to the UCN 3&4 full scope Level 2 PSA. Compared with other existing computer codes for Level 2 PSA, the CONPAS code provides several advanced features: (1) systematic uncertainty analysis / importance analysis / sensitivity analysis, (2) table / graphical display & print, (3) employment of the recent Level 2 PSA technologies, and (4) highly effective user interface. The main purpose of this paper is to introduce the key features of CONPAS code and results of its feasibility study.

• Journal of Ginseng Research
• /
• 제2권1호
• /
• pp.17-33
• /
• 1977

1. 인삼증에 함유된 danlmarane계 glycoside 성분들 중의 한 성분인 panax saponin A(ginsenoside Rgl)(약자 : PSA)에 $^{14}C$ 또는 $^{3}H$를 도입한 방사능 표지 사포닌을 합성하였다. 2. $^{3}H$-PSA의 방사능을 생체내 에서 추적한 결과 PSA는 위장관내에서 쉽게 흡수되어 생체 내 전장기에 골고루 분포된다. 3. 각 장기에 분포된 PSA는 세포 내에 섭취되며 세포 내에 섭취 되는 양은 일정한 포화점이 있다. 4. 포화점을 초과하여 섭취된 PSA는 즉시 뇨를 통하여 배설되며 섭취된 PSA는 세포 내에 장기간 잔유한다.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1246-1254
• /
• 2018

The importance of performing Level 3 probabilistic safety assessments (PSA) along with a general interest in assessing multi-unit risk has been sharply increasing after the Fukushima Daiichi nuclear power plant (NPP) accident. However, relatively few studies on multi-unit Level 3 PSA have been performed to date, reflecting limited scenarios of multi-unit accidents with higher priority. The major difficulty to carry out a multi-unit Level 3 PSA lies in the exponentially increasing number of multi-unit accident combinations, as different source terms can be released from each NPP unit; indeed, building consequence models for the astronomical number of accident scenarios is simply impractical. In this study, a new approach has been developed that employs the look-up table method to cover every multi-unit accident scenario. Consequence results for each scenario can be found on the table, established with a practical amount of effort, and can be matched to the frequency of the scenario. Preliminary application to a six-unit NPP site was carried out, where it was found that the difference between full-coverage and cut-off cases could be considerably high and therefore influence the total risk. Additional studies should be performed to fine tune the details and overcome the limitations of the approach.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권13호
• /
• pp.5261-5264
• /
• 2015

Purpose: To examine the effectiveness of serum free-to-total prostate specific antigen ratio (%fPSA) for the detection of prostate cancer (PCa) in men with different serum total PSA (tPSA) categories. Materials and Methods: From January 2010 to December 2013, a total of 225 patients with lower urinary tract symptoms (LUTS) underwent tPSA and %fPSA measurements. Histological examination with calculation of Gleason score and whole body bone scans were performed in identified cases of PCa. Results: PCa was diagnosed in 44 (19.6%) patients and the remaining 181 patients had benign prostate disease. PCa was detected in 5 (23.8%), 13 (8.7%) and 26 (47.3%) cases with tPSA level ranges ${\leq}4ng/ml$, 4 to 10 ng/ml and >10 ng/ml, respectively. The average Gleason score was $7.2{\pm}0.2$. Some 6 (13.6%) out of 44 PCa patients had bone metastases. The sensitivity was 80% and specificity was 81.3% at the cut-off %fPSA of 15% in PCa patients with a tPSA level below 4 ng/mL. A lower %fPSA was associated with PCa patients with Gleason score ${\geq}7$ than those with Gleason score ${\leq}6$ ($11.7{\pm}0.98$ vs. $16.5{\pm}2.25%$, P=0.029). No obvious relation of %fPSA to the incidence of bone metastasis was apparent in this study. Conclusions: The clinical application of %fPSA could help to discriminate PCa from benign prostate disease in men with a tPSA concentration below 4 ng/mL.

• 대한약침학회지
• /
• 제3권2호
• /
• pp.41-54
• /
• 2000

This study was undertaken to determine if Plantaginis Semen Herbal Acupuncture(PSA) has a protective effect against glycerol-induced acute renal failure in rats. Rats were dehydrated for 24hr and then injected with 8 ml/kg of $50\%$ glycerol, one-half of dose in each hindlimb muscle. In experiments for PSA effect, rats received 0.1 ml of PSA extraction in both sides of corresponding Shenso($BL_{23}$) of human body for 3 days after injection of glycerol. The experimental group were di vided into the Normal group, the Control group, the PSA group. Glycerol injection decreased glomerular filtration rate and increased urine volume, serum creatinine, BUN level and fractional excretion of glucose, $Na^+$, $K^+$ and $CI^-$. These result show that glycerol injection result in acute renal failure. PSA significantly increased glomerular filtration rate and significantly decreased serum creatinine, BUN level and fractional excretion of glucose, $Na^+$ and $CI^-$ as compared Control group. This suggests that PSA could be used in prevention and treatment of acute renalfailure. However, the precise mechanisms of PSA protection remain to be determined.

• Nuclear Engineering and Technology
• /
• 제51권5호
• /
• pp.1297-1306
• /
• 2019

Probabilistic safety assessments (PSA) have been used for several decades to visualize the risk level of commercial nuclear power plants (NPPs). Since the role of a human reliability analysis (HRA) is to provide human error probabilities for safety critical tasks to support PSA, PSA quality is strongly affected by HRA quality. Therefore, it is important to understand the underlying limitations or problems of HRA techniques. For this reason, this study conducted a survey among 14 subject matter experts who represent the HRA community of domestic Korean NPPs. As a result, five significant HRA issues were identified: (1) providing a technical basis for the K-HRA (Korean HRA) method, and developing dedicated HRA methods applicable to (2) diverse external events to support Level 1 PSA, (3) digital environments, (4) mobile equipment, and (5) severe accident management guideline tasks to support Level 2 PSA. In addition, an HRA method to support multi-unit PSA was emphasized because it plays an important role in the evaluation of site risk, which is one of the hottest current issues. It is believed that creating such a catalog of prioritized issues will be a good indication of research direction to improve HRA and therefore PSA quality.