• 한국환경성돌연변이발암원학회:학술대회논문집
• /
• 한국환경성돌연변이발암원학회 2002년도 Molecular and Cellular Response to Toxic Substances
• /
• pp.198-198
• /
• 2002

• 한국환경성돌연변이발암원학회지
• /
• 제19권2호
• /
• pp.95-101
• /
• 1999

Risk Assessment is an important area in toxicology and the methodology for risk assessment has been developed. Mathematical models used for risk assessment include one-hit multi-hit, two-stage, probit logistic, multistage, and linearized multistage models. For the assessment of exposure dose, environmental monitoring has been applied, but it has limitation to accurately assess exposure level because the levels in the air, water, foods, and soil may vary depending on time of sampling. In addition, humans can be exposed to various sources of exposure and thus it will be impossible to estimate the total level of exposure in humans by environmental monitoring. To eliminate the limitation of environmental monitoring, a direct measurement of toxic materials or modified biomolecules (called biomarkers) associated with the exposure of toxic materials is needed. Here, scientific basis of biomarkers and future direction have been considered for the assessment of carcinogen exposure and cancer risk in humans.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2002년도 Molecular and Cellular Response to Toxic Substances
• /
• pp.198-198
• /
• 2002

Occurrence of Chinese Herbs Nephropathy (CHN) has been reported in young women who had taken a slimming pills containing some chinese herbs. Aristolochic acid (AA) known as a carcinogen, was suspected as the major causal factor of CHN. AA is major component of fruit of A. contorta was used in Korean Traditional Medicine.(omitted)

• 한국의학물리학회지:의학물리
• /
• 제28권3호
• /
• pp.111-121
• /
• 2017

Verification of dose distribution is an essential part of ensuring the treatment planning system's (TPS) calculated dose will achieve the desired outcome in radiation therapy. Each measurement have uncertainty associated with it. It is desirable to reduce the measurement uncertainty. A best approach is to reduce the uncertainty associated with each step of the process to keep the total uncertainty under acceptable limits. Point dose patient specific quality assurance (QA) is recommended by American Association of Medical Physicists (AAPM) and European Society for Radiotherapy and Oncology (ESTRO) for all the complex radiation therapy treatment techniques. Relative and absolute point dose measurement methods are used to verify the TPS computed dose. Relative and absolute point dose measurement techniques have a number of steps to measure the point dose which includes chamber cross calibration, electrometer reading, chamber calibration coefficient, beam quality correction factor, reference conditions, influences quantities, machine stability, nominal calibration factor (for relative method) and absolute dose calibration of machine. Keeping these parameters in mind, the estimated relative percentage uncertainty associated with the absolute point dose measurement is 2.1% (k=1). On the other hand, the relative percentage uncertainty associated with the relative point dose verification method is estimated to 1.0% (k=1). To compare both point dose measurement methods, 13 head and neck (H&N) IMRT patients were selected. A point dose for each patient was measured with both methods. The average percentage difference between TPS computed dose and measured absolute relative point dose was 1.4% and 1% respectively. The results of this comparative study show that while choosing the relative or absolute point dose measurement technique, both techniques can produce similar results for H&N IMRT treatment plans. There is no statistically significant difference between both point dose verification methods based upon the t-test for comparing two means.

• 미생물학회지
• /
• 제49권4호
• /
• pp.360-368
• /
• 2013

최근 국내의 각종 시설들에서 경관과 여름철 물놀이를 위한 바닥분수 설치가 선호되어, 그 수가 연간 50% 이상 급증하고 있다. 본 연구는, 정량적 미생물학적 위해성 평가 방법으로, 아동이 바닥분수에서 물놀이를 하는 동안 Legionella spp.에 의한 감염 위해도가 어느 정도인지 정량 하였다. 용수 중 Legionella균의 농도를 $10^{-1}-10^6$ CFU/L로 상정하고, 공기 중으로 에어로졸과 함께 비산하게 되는 Legionella균의 농도와 노출시간, 호흡률의 분포, 폐까지 도달하는 에어로졸의 비율을 곱하여 아동들의 노출량을 산정하고, Legionella pneumophila의 위해도를 도출하는 것으로 알려진 지수함수 모델에 따라, 감염 위해도로 변환하였다. 최고 위험군은 뛰어다니면서 물놀이를 하는 신체가 큰, 혹은 연령이 높은 아동이었으며, 이들이 $10^4$ CFU/L 이상의 Legionella균이 존재하는 분수 용수를 1회 이상 이용 시 0.05 이상의 위해도가 발생하였다. 이 결과에 따르면, $10^3$ CFU/L 미만의 Legionella균 농도를 공중이용시설의 모든 배관용수에 대하여 허용하는 현행 질병관리본부의 레지오넬라증 관리지침은 타당한 것으로 판정된다. 그러나, 이 기준은 건강한 성인 대상으로는 적합하나 아동의 면역력이 낮은 점을 감안하지 않았으므로, 아동에게 적합한 감염위해도 모델을 연구하여, 보다 철저한 관리 기준을 적용할 필요성이 있다.

• Nuclear Engineering and Technology
• /
• 제25권3호
• /
• pp.437-446
• /
• 1993

가동중 원자력 시설에서 방출되는 방사성 핵종의 년간 인체 흡수량을 보다 현실적으로 평가하기 위한 계산 모델을 수립하였다. 이 모델을 적용하기 위해서는 평가년도 중에 소비되는 식량 및 사료 작물의 수확년도와 실제 가동된 전기간내 매년의 공기중 및 수중 평균농도가 고려되어야 한다. 한국인에 대한 평형 섭식경로 평가코드인 KFOOD 코드를 수립된 계산모델에 따라 수정하였다. 가상적인 10 년간의 균일방출에 대하여 개선된 방식, KFOOD 방식, 그리고 또다른 현존 방식에 의한 평가가 이루어 질 수 있도록 입력 데이타 파일을 차례로 변경하여 수정된 코드를 실행시키고 세가지 결과들을 비교하였다. Mn-54, Co-60, Sr-90, I-131 그리고 Cs-137의 흡수를 통한 한국 성인의 년간 예탁실효선량을 개선된 방식으로 계산한 결과는 KFOOD 방식에 비해 각각 11, 2, 5, 60, 3%정도 낮았다. 개선된 방식에 따른 평가에 있어서는 Sr-90을 제외한 핵종들의 인체흡수에 대해서는 엽면흡수 경로의 기여가 훨씬 컸으나 Sr-90의 경우에는 뿌리흡수 경로의 기여가 훨씬 컸다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제43권5호
• /
• pp.337-341
• /
• 2020

Although the screening with a mammography has been shown to be economical, simple and effective in detecting breast cancer, it is accompanied by the risk from radiation. Therefore, this study analyzed the glandular dose and organ dose according to the target-filter combination and the presence and absence of implants using Monte Carlo simulation. The results indicate that at a tube voltage of 30 kV and a tube current of 50 mAs, the dose increased in the order of Mo/Mo. Mo/Rh, Rh/Rh and W/Rh in proportion to the atomic number of the target-filter. In addition, in phantom without implant a reduction in dose was seen when compared to the phantom with implant. The organ dose was highest in the lens except for the breast on the examination side regardless of the presence or absence of the implant. These results may contribute to use basic data for the diagnostic reference level of breast plastic surgery patients.

• 치과방사선
• /
• 제25권2호
• /
• pp.309-318
• /
• 1995

In head and neck region, the critical organ and tissue doses were determined, and the risks were estimated from lateral, posteroanterial and basilar cephalometric radiography. For each cephalometric radiography, 31 TLDs were placed in selected sites(18 internal and 13 external sites) in a tissue-equivalent phantom and exposed, then read-out in the TLD reader. The results were as follows: 1. From lateral cephalometric radiography, the highest effective dose recorded was that delivered to the salivary gland(3.6pSv) and the next highest dose was that received by the bone marrow(3pSv). 2. From posteroanterial cephalometric radiography, the highest effective dose recorded was that delivered to the salivary gland(2pSv) and the next highest dose was that received by the bone marrow(1.8pSv). 3. From basilar cephalometric radiography, the highest effective dose recorded was that delivered to the thyroid gland(31A p Sv) and the next highest dose was that received by the salivary gland(13.3 p Sv). 4. The probabilities of stochastic effect from lateral, posteroanterial and basilar cephalometric radiography were $0.72{\times}10^{-6}$, $0.49{\times}10^{-6}$ and $3.51{\times}10^{-6}$, respectively

• 한국임상약학회지
• /
• 제22권4호
• /
• pp.291-303
• /
• 2012

As respiratory tract infections (RTI) account for about 60% of all antibiotic prescriptions in outpatient care setting, there are significant concerns about emerging resistance that are largely due to the excessive or inappropriate use of antibacterial agents for viral respiratory infections. This study was aimed to develop retrospective drug utilization review (DUR) program of antibiotics for RTIs using Delphi methods. Retrospective DUR criteria of antibiotics for RTIs were identified based on clinical practice guidelines and opinion of experts. Expert panel members were clinical doctors and pharmacists and Delphi method was applied by survey on 16 members of panels. The claim data from Korean Health Insurance Review & Assessment (HIRA) were used to examine trends in outpatient antibiotic prescription between Janunary to December of 2008. As results, Quality index for RTI was assessed for the claim type, antibiotics use of quantity, duration, number and cost. Antibiotic prescription rate for RTIs, Defined Daily Dose (DDD), and duration of antibiotics use were more recognized as significant quality index by experts' opinion. Use of first line agents suggested by guidelines was low and duration of antibiotics use was shorter compared to the recommendations. Antibiotics were over prescribed for RITs. However, dose and duration of antibiotics were under-used.

• 한국물환경학회지
• /
• 제22권6호
• /
• pp.1107-1108
• /
• 2006

As expanding municipal and industrial areas since started the economic development plan in earnest in 1970's, the water resource, mainly river surface water has been seriously polluted. Nevertheless, being upgraded in their treatment technologies for the drinking water, the safety has been issued one of crucially social problem in Korea. The water authorities has tried to improve the quality such as amending the drinking water quality standard to be monitored; hazardous chemicals and microorganis have been added and now 55 items, before 47 items, since in 2002. The Water Authorities of Seoul, the capital city of Korea, planned to assess the safty of drinking water quality after amended the standard. This study was conducted to assess the risk due to polluted chemicals including 21 heavy metals, VOCs, pesticides, PAHs, DBPs and organic chemicals among the regulated items. The risk assessment were undertaken hazard identification, exposure assessment, dose-response assessment and risk characterization. For the exposoure assessment, tap water, bottled water and purified water were sampled and analyzed in February, 2004. Risk characterization of detected chemicals was categorized into carcinogenecity and noncarcinogenecity, and estimated the excess of carcinogens and compapared with the reference dose (RfD) of noncarcinogenns. The excess risk of carcinogens from samples were considered comparatively in the acceptable levels; $10^{-6}$ for cancer risk and hazard quotient (HQ) 1.0 for noncancer risk. The deteced levels were estimated in $10^{-5}{\sim}10^{-6}$ of cancer risk and below 1.0 of HQ of noncancer risk. While three kinds of water were determined within the acceptal levels, DBPs were detected in tap water and purified were and some undesireable chemicals such as more fluoride detected rather than the quality stanadard. For the drinking water safety, it shoud be continuously monitored, assessed and managed as well risk communiction between the authoritis and public.