Dose reconstruction modeling for medical radiation workers

Yeongchull Choi,Eun Shil Cha,Won Jin Lee 대한방사선방어학회 2017 대한방사선방어학회 학술발표회 논문요약집 Vol.2017 No.04

Reconstruction of Radiation Dose Received by Diagnostic Radiologic Technologists in Korea

Choi, Yeongchull,Kim, Jaeyoung,Lee, Jung Jeung,Jun, Jae Kwan,Lee, Won Jin The Korean Society for Preventive Medicine 2016 Journal of Preventive Medicine and Public Health Vol.49 No.5

Objectives: Diagnostic medical radiation workers in Korea have been officially monitored for their occupational radiation doses since 1996. The purpose of this study was to design models for reconstructing unknown individual radiation doses to which diagnostic radiation technologists were exposed before 1996. Methods: Radiation dose reconstruction models were developed by using cross-sectional survey data and the personal badge doses of 8167 radiologic technologists. The models included calendar year and age as predictors, and the participants were grouped into six categories according to their sex and facility type. The annual doses between 1971 and 1995 for those who were employed before 1996 were estimated using these models. Results: The calendar year and age were inversely related to the estimated radiation doses in the models of all six groups. The annual median estimated doses decreased from 9.45 mSv in 1971 to 1.26 mSv in 1995, and the associated dose variation also decreased with time. The estimated median badge doses from 1996 (1.22 mSv) to 2011 (0.30 mSv) were similar to the measured doses (1.68 mSv to 0.21 mSv) for the same years. Similar results were observed for all six groups. Conclusions: The reconstruction models developed in this study may be useful for estimating historical occupational radiation doses received by medical radiologic technologists in Korea.

Economic burden of acute pesticide poisoning in South Korea

Choi, Yeongchull,Kim, Younhee,Ko, Yousun,Cha, Eun S.,Kim, Jaeyoung,Lee, Won J. Blackwell Publishing Ltd 2012 Tropical medicine & international health Vol.17 No.12

<P><B>Abstract</B></P><P><B>Objectives </B> To investigate the magnitude and characteristics of the economic burden resulting from acute pesticide poisoning (APP) in South Korea.</P><P><B>Methods </B> The total costs of APP from a societal perspective were estimated by summing the direct medical and non‐medical costs together with the indirect costs. Direct medical costs for patients assigned a disease code of pesticide poisoning were extracted from the Korean National Health Insurance Reimbursement Data. Direct non‐medical costs were estimated using the average transportation and caregiving costs from the Korea Health Panel Survey. Indirect costs, incurred by pre‐mature deaths and work loss, were obtained using 2009 Life Tables for Korea and other relevant literature.</P><P><B>Results </B> In 2009, a total of 11 453 patients were treated for APP and 1311 died, corresponding to an incidence of 23.1 per 100 000 population and a mortality rate of 2.6 per 100 000 population in South Korea. The total costs of APP were estimated at approximately US<TEX>$ 150 million, 0.3% of the costs of total diseases. Costs due to pre‐mature mortality accounted for 90.6% of the total costs, whereas the contribution of direct medical costs was relatively small.</P><P><B>Conclusion </B> Costs from APP demonstrate a unique characteristic of a large proportion of the indirect costs originating from pre‐mature mortality. This finding suggests policy implications for restrictions on lethal pesticides and safe storage to reduce fatality and cost due to APP.</P>

시스템생물학의 한의학적 응용

박영철,이선동,Park, Yeongchul,Lee, Sundong 대한예방한의학회 2016 대한예방한의학회지 Vol.20 No.1

In Korea and China, traditional medicine's holistic approaches, based on the views of whole-body and whole-person, have been applied to make the solution of health problem. However, these holistic approaches of traditional korea or chinese medicine have been limited in interpreting their theories in a view of modern scientific aspects of medicine. This limitation seems to be mainly due to the reductionism approaches of modern scientific medicine. Traditionally, science has taken a reductionism approach; dissecting biological systems into their constituent parts and studying them in isolation. However, systems biology based on omics technologies is providing a new thought and method for traditional medicine's research and interpretation. Systems biology uses integrity study as the characteristic and bioinformatic technology as the key method for connecting reductionism and holism. Therefore, it has much in common with the theory of traditional medicine. It was reviewed that how systems biology is applied to traditional medicine in Korea and China. Also it was suggested that more future researches on interpretation between traditional medicine and systems biology must be focused on personalized medicine since systems biology will have a major impact on future personalized therapeutic approaches.

일부 동물성 한약재의 독성과 안전성등급화 - 봉독, 사독, 반묘와 오공을 중심으로 -

박영철,이선동,Park, Yeongchul,Lee, Sundong 대한예방한의학회 2016 대한예방한의학회지 Vol.20 No.1

Objectives : About 13% of the medicines used by traditional korean medicines(TKM), are called animal medicines and are derived from non-herbal sources such as animals and insects. However, the clinical use of these preparations from animal medicines is often based on tradition and belief, rather than on evidence of toxicity and efficacy. As a result, animal medicines containing toxin have caused serious problems from injecting patients with venom. Here, various venoms frequently used as TKM were reviewed in terms of their instinct toxity and tried to estimate their safety classification. Methods : The estimation of safety classification was based on human equivalent dose(HED)-based MOS (margin of safety) and clinical dose applied for patients. Results and Conclusions : Except that of snake venom due to no clinical dose, they were evaluated as class 3 for bee venom, class 4 for cantharidin, toxin from blister beetle, and class 1 for venom from scolopendrid. In conclusion, animal medicines showed a wide range of safety classification from class 1 to class 4. This wide range is estimated to result from extremely limited applications of each venom for patients because of their strong toxicity. However, it should be cautious for application in clinics since animal medicines can produce anaphylactic reactions particularly after veinous administration even with a tiny amount of venom.

Work procedures and risk factors for high radiation exposure among radiologic technologists in South Korea

Jaeyoung Kim,EunShil Cha,Yeongchull Choi,Won Jin Lee 대한방사선방어학회 2016 대한방사선방어학회 학술발표회 논문요약집 Vol.2016 No.12

백부자-대체 가능 한약재의 계종버섯에 대한 급성독성시험과 안전성등급화

안민지 ( Minji An ),박영철 ( Yeongchul Park ) 대한본초학회 2017 大韓本草學會誌 Vol.32 No.4

Objectives : Termitomyces albuminosus (Berk.) Heim is one of the famous wild edible mushrooms in the southern part of China. It is known that Termitomyces albuminosus, like Aconitum koreanum used in Korean traditional medicine, contains a kind of cerebroside, termitomycesphin, causing a pharmacologic effect on the neuron system. The pharmacologic effect of Termitomyces albuminosus can be used to possibly replace Aconitum koreanum. However, It needs to be certified as safe before it can be used. Here, a single-oral toxicity test and safety classification was conducted to obtain acute information of the toxicity of dried-Termitomyces albuminosus powder and to secure its safety in clinical applications. Methods : In order to calculate approximate lethal dose(ALD), test substance was orally administered to male and female SD-rat at dose levels of 5,000 and 0 (vehicle control) ㎎/㎏ (body weight). Based on the result of this toxicity, also the estimation of safety classification was calculated using the HED-based (human equivalent dose) MOS (margin of safety). Results : There were no mortalities, test substances treatment-related clinical signs, no changes in the body or organ weights, and no gross or histopathological findings at 14 days after treatment with test substance. Thus, the approximate lethal dose of dried-Termitomyces albuminosus powder was considered over 5,000 ㎎/㎏ in both female and male mice. Conclusions : Based on the limit dose, 5000 ㎎/㎏, it was estimated that dried-Termitomyces albuminosus powder is classified as “Specified class B” indicating that clinical dose is not limited to patients as safe as food.

마우스의 기도 내 점적을 통한 가습기살균제 CMIT/MIT와 사망 간의 원인적 연관성에 관한 연구

김하영(Hayoung Kim),정용현(Yonghyun Chung),박영철(Yeongchul Park) 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.4

Objectives: The deaths of Korean victims exposed to the disinfectant CMIT/MIT have remained unresolved. This is mainly due to a lack of concordance between the few available toxicity tests and the abundant epidemiological data, making it difficult to establish a cause-and-effect relationship. Therefore, this study was carried out to investigate any potential associations between CMIT/MIT exposure and death. Methods: Groups of experimental and control C57BL/6 mice were instilled (in the trachea) with chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) using a visual instillobot. CMIT/MIT was instilled over a period of three days and eight weeks, respectively, to achieve acute and chronic exposures. A threshold dose-response model was applied for estimating the threshold level as one line of evidence for a causal association between CMIT/MIT and death. Results: An acute exposure of 1.2 mg ai/kg/day of CMIT/MIT was estimated to reflect the threshold for death. The dose-response curve with this threshold showed a very steep slope and a narrow range of CMIT/MIT exposures. The narrow range of CMIT/MIT exposures, in particular, indicated an evident boundary between survival and death, thus implicating a strong causal association. A similar threshold dose-response relationship observed following acute exposure was also seen following chronic exposure to CMIT/MIT. Airborne disinfectant exposure was visible as minimal or mild lung damage with no fibrosis, as shown by histopathological tests. However, many observations are considered to be functional respiratory tract or lung failure due to death, as observed in necropsies of the mice that died due to CMIT/MIT exposures. Conclusions: There are two strong lines of evidence for a causal association between death and CMIT/MIT exposure: 1) The threshold dose-response curve, with a very steep slope and a narrow range of CMIT/MIT exposures showing a visible boundary between survival and death; and 2) many cases of functional respiratory or lung failure.

The Burden of Acute Pesticide Poisoning and Pesticide Regulation in Korea

Ko, Seulki,Cha, Eun Shil,Choi, Yeongchull,Kim, Jaeyoung,Kim, Jong-Hun,Lee, Won Jin KOREAN ACADEMY OF MEDICAL SCIENCE 2018 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.33 No.31

<P><B>Background</B></P><P>This study aimed to estimate the burden of acute pesticide poisoning and to determine its trend with recently implemented pesticide regulations.</P><P><B>Methods</B></P><P>Disability-adjusted life-years (DALYs) were calculated as the sum of years of life lost (YLLs) and years lived with disability (YLDs) due to acute pesticide poisoning using the methods of the Global Burden of Disease Study 2013. The values of YLLs, YLDs, and DALYs were stratified by sex, age groups, intentionality of poisoning, and causative agents.</P><P><B>Results</B></P><P>From 2006 to 2014, DALYs decreased by 69% (from 69,550 to 21,742). The decreasing tendency of DALYs was especially marked from 2011. The total burden of acute pesticide poisoning was mainly caused by YLLs and intentional pesticide poisoning. The highest DALYs due to acute pesticide poisoning occurred in those in their 40s and 50s; however, the decreased rates of DALYs were higher in those aged 10–49 years than in those aged more than 50 years. Herbicides including paraquat contributed to the largest proportion of total DALYs.</P><P><B>Conclusion</B></P><P>As this is the first study to quantify the burden of acute pesticide poisoning using DALYs, our results provide comprehensive evidence of the importance of using strict regulations to prevent public health hazards due to acute pesticide poisoning.</P>

한방의료기관이용환자의 부작용 및 독성발생의 특성

이기범(Ki-Bum Lee),박영철(Yeongchul Park),이선동(Sundong Lee) 대한한의학회 2016 대한한의학회지 Vol.37 No.1