The effects of low-dose radiation therapy in patients with mild-to-moderate Alzheimer’s dementia: an interim analysis of a pilot study

Aryun Kim(Aryun Kim),Jeonghwan Lee(Jeonghwan Lee),Hansol Moon(Hansol Moon),Chulhan Kim(Chulhan Kim),Min Young Yoo(Min Young Yoo),Woo Yoon Park(Woo Yoon Park),Won Dong Kim(Won Dong Kim),Young-Seok Seo( 대한방사선종양학회 2023 Radiation Oncology Journal Vol.41 No.2

Purpose: We aimed to determine whether low-dose radiotherapy (LDRT) is effective in patients with Alzheimer disease (AD). Materials and Methods: We included patients according to the following criteria: probable Alzheimer's dementia according to the New Diagnostic Criteria for Alzheimer’s Disease; confirmation of amyloid plaque deposits on baseline amyloid positron emission tomography (PET); a Korean Mini-Mental State Examination 2nd edition (K-MMSE-2) score of 13–26; and a Global Clinical Dementia Rating (CDR) score of 0.5–2 points. LDRT was performed six times at 0.5 Gy each. Post-treatment cognitive function tests and PET-CT examinations were performed to evaluate efficacy. The medication for AD treatment was maintained throughout the study period. Results: At 6 months after LDRT, neurological improvement was seen in 20% of patients. Patient #2 showed improvement in all domains of the Seoul Neuropsychological Screening Battery II (SNSB-II). Moreover, the K-MMSE-2 and Geriatric Depression Score-Short Form scores improved from 20 to 23 and from 8 to 2, respectively. For patient #3, the CDR score (sum of box score) improved from 1 (4.0) to 1 (3.5) at 3 months follow-up. Moreover, the Z scores for language and related functions, memory, and frontal executive function improved to -2.56, -1.86, and -1.32, respectively at the 6-month follow-up. Two patients complained of mild nausea and mild hair loss during LDRT, which improved after treatment. Conclusion: One of the five patients with AD treated with LDRT experienced a temporary improvement in SNSB-II. LDRT is tolerable in patients with AD. We are currently under follow-up and will conduct cognitive function tests after 12 months after LDRT. A large-scale randomized controlled trial with a longer follow-up period is warranted to determine the effect of LDRT on patients with AD.

Subspace based face synthesis method for cancelable face biometrics

Chulhan Lee,Hyunggu Lee,Jeung-Yoon Choi,Jongsun Kim,Jaihie Kim 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

The Impact of the Amendment of the Health Insurance Coverage for F-18 Fluorodeoxyglucose Positron Emission Tomography on the Healthcare Behaviors for Breast Cancer: An Interrupted Time Series Analysis of the Korean National Data From 2013 to 2018

Kim Chulhan,Chun Sung-Youn,Kim Sun Jung,Yang Ki Hwa,Baek Ji Hyeon,Shin Ji Hyeon,Yoo Ji Won,Chang Young Woo,Kang Keon Wook,Hwang Jinwook 대한의학회 2022 Journal of Korean medical science Vol.37 No.19

Background: F-18 Fluorodeoxyglucose positron emission tomography (F-18 FDG PET), which can cover the body from the skull base to the thigh in one scan, is beneficial for evaluating distant metastasis. F-18 FDG PET has interested policymakers because of its relatively high cost. This study investigated the effect of the F-18 FDG PET reimbursement criteria amendment on healthcare behavior in breast cancer using an interrupted time series (ITS) analysis. Methods: We retrospectively analyzed the inpatient and outpatient data from Korea’s Health Insurance Review and Assessment Service (HIRA) from January 1, 2013 to December 31, 2018. ITS analysis was performed for the number of each medical imaging modality and the total medical imaging cost of the breast cancer patients. Results: The annual number of breast cancer patients has been increasing steadily since 2013. The trend of F-18 FDG PET increased before the reimbursement criteria was amended, but intensely decreased immediately thereafter. The chest and abdomen computed tomography scans showed a statistically significant increase immediately after the amendment and kept steadily increasing. A change in the total medical imaging cost for the breast cancer patient claimed every month showed an increasing trend before the amendment (β = 5,475, standard error [SE] = 1,992, P = 0.008) and rapid change immediately after (β = −103,317, SE = 16,152, P < 0.001). However, there was no significant change in the total medical imaging cost at the long-term follow-up (β = −912, SE = 1,981, P = 0.647). Conclusion: Restriction of health insurance coverage for cancer may affect healthcare behaviors. To compensate for it, the policymakers must consider this and anticipate the impact following implementation.

A Study of Changeable Biometrics for Fingerprint Recognition

Chulhan Lee,Hyunggu Lee,Jeung-Yoon Choi,Jaihie Kim 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

To enhance security and privacy in biometric systems, changeable (or cancelable) biometric systems have been developed. These systems can revoke and re-issue biometric data when it is compromised. The proposed method generates changeable fingerprint templates by using a single reference point. In our experiments, performance the proposed method were evaluated and the experimental results showed that the proposed method is a useful way of constructing changeable biometric systems.

The Method of Iris Region Extraction for Iris Recognition

ChulHan Lee,SeungIn No,Jaihie Kim 대한전자공학회 2003 ITC-CSCC :International Technical Conference on Ci Vol.2003 No.7

가변 얼굴 영상의 합성 방법에 관한 연구

이형구(Hyunggu Lee),이철한(Chulhan Lee),최정윤(Jeung-Yoon Choi),김재희(Jaihie Kim) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.11

Cancelable biometrics has been introduced for secure usage of biometric data in biometric recognition system. Cancelable template is a revocably and non-invertibly transformed version of original biometric data. Normally, the face biometric data can be interpreted by machine and human. However, due to non-invertible transform, cancelable template cannot be understood by human. In this paper, we propose a method about human interpretable face image synthesis. Because, face image is synthesized using revocable cancelable template, synthesized face image is also revocable. In other words, we can simply regenerate face image with newly issued cancelable template.

Online signature verification using temporal shift estimated by the phase of Gabor filter

Yi, Jonghyon,Lee, Chulhan,Kim, Jaihie Institute of Electrical and Electronics Engineers 2005 IEEE transactions on signal processing Vol.55 No.1

A new online signature-verification method using temporal shift estimation is presented. Local temporal shifts existing in signatures are estimated by the differences of the phase outputs of Gabor filter applied to signature signals. In the proposed signature-verification algorithm, an input signature signal undergoes preprocessing procedures including smoothing, size normalization and skew correction, and then its feature profile is extracted from the signature signal. A Gabor filter with the predetermined center frequency ω is applied on a feature profile, and a phase profile is computed from the phase output. The feature profile and the phase profile are length normalized and quantized so that a signature code of fixed size is generated. The temporal shifts existing between two signatures are computed by using the differences between the phase profiles. The information about the temporal shifts is used as offsets for comparing the two feature profiles. Therefore, two kinds of dissimilarities are proposed. Temporal dissimilarity is a measure reflecting the amount of total temporal disturbance between the two signatures. The difference between the two signature profiles is computed at each corresponding point pair and is accumulated into temporally arranged feature profile dissimilarity. The decision boundary is represented as a straight line in the dissimilarity space whose two axes are the two dissimilarity measures. The slope and the position of the decision boundary are computed using the distribution of the dissimilarities among the sample signatures involved in the enrollment procedure. The experimental results show that through the compact and fixed size of signature data representation and relatively simple comparison methods, the proposed method can compare signatures 400 times faster than the conventional DP matching based signature-verification method.

Evaluation of Green House Gases (GHGs) Reduction Plan in Combination with Air Pollutants Reduction in Busan Metropolitan City in Korea

Jang Pyo Cheong,Chulhan Kim,장재수 한국대기환경학회 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.4

Since most Green House Gases (GHGs) and air pollutants are generated from the same sources, it will be cost-effective to develop a GHGs reduction plan in combination with simultaneous removal of air pollutants. However, effects on air pollutants reduction according to implementing any GHG abatement plans have been rarely studied. Reflecting simultaneous removal of air pollutants along with the GHGs emission reduction, this study investigated relative cost effectiveness among GHGs reduction action plans in Busan Metropolitan City. We employed the Data Envelopment Analysis (DEA), a methodology that evaluates relative efficiency of decision-making units (DMUs)producing multiple outputs with multiple inputs, for the investigation. Assigning each GHGs reduction action plan to a DMU, implementation cost of each GHGs reduction action plan to an input, and reduction potential of GHGs and air pollutants by each GHGs reduction action plan to an output, we calculated efficiency scores for each GHGs reduction action plan. When the simultaneous removal of air pollutants with the GHGs reduction were considered, green house supply-insulation improvement and intelligent transportation system (ITS) projects had high efficiency scores for cost-positive action plans. For cost-negative action plans, green start network formation and running, and daily car use control program had high efficiency scores. When only the GHGs reduction was considered, project priority orders based on efficiency scores were somewhat different from those when both the removal of air pollutants and GHGs reduction were considered at the same time. The expected action plan priority difference is attributed to great difference of air pollutants reduction potential according to types of energy sources to be reduced.

노이즈에 강인한 지문 융선의 방향 추출 알고리즘

이상훈(Sanghoon Lee),이철한(Chulhan Lee),최경택(Kyoungtaek Choi),김재희(Jaihie Kim) 대한전자공학회 2008 電子工學會論文誌-SP (Signal processing) Vol.45 No.1

지문의 방향 정보는 융선 강화, 정합, 분류기 등과 같이 전반적인 지문 인식 알고리즘의 기반 정보로 사용하므로 방향 정보의 오차는 지문 인식 성능에 직접적인 영향을 준다. 지문의 방향은 대부분의 영역에서는 융선의 흐름이 완만하게 변하는 전역적인 특성과 중심점(core point)이나 삼각주(delta point)와 같은 특이점(singular point) 부근에서 융선의 흐름이 급격히 변하는 지역적인 특성을 모두 갖고 있다. 따라서 융선의 방향 추출 시에 지역적인 특성만 강조하면 특이점 부근에서의 방향 변화를 민감하게 표현해 줄 수 있지만 노이즈에 취약한 단점이 발생하고 전역적인 특성만 강조하면 노이즈에 강인한 특성을 보이지만 특이점 부근에서 방향 변화에 둔감해진다. 본 논문에서는 지역적인 특성에 민감하면서도 노이즈에 강인한 적응적 지문 방향 추출 방법에 대하여 제안하였다. 또한, 상처에 의해 발생되는 방향성 노이즈는 반복 회귀 진단으로 이상치(outlier)들을 선별하여 제거함으로써 이에 대한 영향을 최소화하였다. 그리고 영역별로 측정 사이즈를 다르게 하여 노이즈에 강인하면서 특이점 부근에서는 융선 변화에 민감하게 방향을 추정하였다. 제안 방법의 평가를 위해 인조 지문(synthetic fingerprint)과 지문 인식의 성능 평가용으로 많이 사용되는 FVC 2002 데이터베이스를 사용하였다. 융선 방향 추출의 정확성은 융선의 방향 값을 사전에 알고 있는 인조 지문 데이터를 생성하여 평가하였고 최종 지문 인식 성능의 평가는 FVC 2002 데이터베이스를 사용하였다. Ridge orientations of fingerprint image are crucial informations in many parts of fingerprint recognition such as enhancement, matching and classification. Therefore it is essential to extract the ridge orientations of image accurately because it directly affects the performance of the system. The two main properties of ridge orientation are 1) global characteristic (gradual change in whole part of fingerprint) and 2) local characteristic (abrupt change around core and delta points). When we only consider the local characteristic, estimated ridge orientations are well around singular points but not robust to noise. When the global characteristic is only considered, to estimate ridge orientation is robust to noise but cannot represent the orientation around singular points. In this paper, we propose a novel method for estimating ridge orientation which represents local characteristic specifically as well as be robust to noise. We reduce the noise caused by scar using iterative outlier rejection. We apply adaptive measurement resolution in each fingerprint area to estimate the ridge orientation around singular points accurately. We evaluate the performance of proposed method using synthetic fingerprint and FVC 2002 DB. We compare the accuracy of ridge orientation. The performance of fingerprint authentication system is evaluated using FVC 2002 DB.

Multiresolution Independent Component Analysis for Its Iris Identification

Seung-In Noh,Kwanghuk Pae,Chulhan Lee,Jaihie Kim 대한전자공학회 2002 ITC-CSCC :International Technical Conference on Ci Vol.2002 No.7