• Title/Summary/Keyword: Estimated Radiation dose

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Radiation-induced DNA strand breaks in EL4 cells and mouse spleen lymphocytes (방사선에 의한 EL4 마우스 백혈병세포 및 정상 마우스 비장 임파구 DNA strand breaks의 측정)

  • Kim, Sung-ho;Kim, Tae-hwan;Chung, In-yong;Yoo, Seong-yul;Cho, Chul-koo;Chin, Soo-yil
    • Korean Journal of Veterinary Research
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    • v.31 no.3
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    • pp.329-335
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    • 1991
  • The filter elution technique was used to assay $^{60}Co$ $\gamma$ ray-induced DNA strand breaks(SB) in EL4 mouse leukemia cell and mouse spleen lymphocyte. The lymphocytes were stimulated with lipopolysaccharide (LPS, $20{\mu}g/ml$) to label $[^3H]$ thymidine. EL4 cells and lymphocytes in suspension were exposed at $0^{\circ}C$ to 0Gy, 1Gy, 5Gy, 10Gy or l5Gy for DNA single strand breaks(SSB) assay and 0Gy, 25Gy, 50Gy, 75Gy or 100Gy for DNA double strand breaks(DSB) assay of $^{60}Co$ radiation and elution procedure was performed at pH12.1 and 9.6. The number of DNA strand breaks increased with increasing doses of r rays. The strand scission factor(SSF) was estimated in each experiment (eluted volume 21ml). The slope of SSB EL4 cells was $0.01301{\pm}0.00096Gy^{-1}$ (n=5), the slope of SSB for lymphocytes was $0.01097{\pm}0.00091Gy^{-1}$ (n=5) and the slope of DSB for lymphocytes was $0.001707{\pm}0.0000573Gy^{-1}$ (n=5). Thus EL4 cells were more sensitive to induction of DNA SSB by ionizing radiation than lymphocytes (p<0.005). The ratio of slope of dose-response relationship (SSF versus dose) of lymphocytes DNA SSB as compared with the slope of DNA DSB was 6.4.

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Effective Dose Equivalent due to Inhalation of Indoor Radon-222 Daughters in Korea (한국인의 라돈-222 자핵종 호흡 실효선량당량 평가)

  • Chang, Si-Young;Ha, Chung-Woo;Lee, Byoung-Hun
    • Journal of Radiation Protection and Research
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    • v.16 no.1
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    • pp.1-13
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    • 1991
  • Effective dose equivalents resulting from inhalation of indoor radon-222 daughters at 12 residential areas in Korea were assessed by a simple mathematical lung dosimetry model based on the measurements of long-term averaged radon concentrations at 340 dwellings. The long-term averaged indoor radon-222 concentrations and corresponding eqilibrium equivalent radon $concentration(EEC_{Rn})$ measured by passive time-integrating CR-39 radon cups are in the range of $33.82{\sim}61.42Bq/m^3(median\;:\;48.90Bq/m^3)$ and of $13.53{\sim}24.57Bq/m^3(median\;:\;19.55Bq/m^3)$, respectively. The effective dose equvalent conversion factor for the exposure to unit $EEC_{Rn}$ derived in this study was estimated $1.07{\times}10^{-5}mSv/Bq\;h\;m^{-3}$ for a reference adult and agreed well with those recommended by the ICRP and UNSCEAR. The annual average dose equivalent to the lung $(H_{LUNG})$ from inhalation exposure to measured $EEC_{Rn}$ was estimated to be 20.90 mSv and resulting effective dose $equivalent(H_E)$ was to be 1.25 mSv, which is about 50% of the natural radiation exposure of 2.40 mSv/y to the public reported by the UNSCEAR.

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Single and Fractionated Irradiation of Mammary Tumor of Rat (백서 유방암의 단일 및 분할 조사시 방사선치료 효과)

  • Ha, Sung-Whan;Huh, Seung-Jae;Park, Charn-Il
    • Radiation Oncology Journal
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    • v.2 no.2
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    • pp.173-175
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    • 1984
  • The therapeutic effect of mammary breast cancer of rat (Sprague Dawley) was estimated by single and 5 fractionated irradiation of $Co^{60}-\gamma-ray$. Response rates over 50a were 20, 43, 67, $80\%$ respectively by single dose irradiation of 800, 1,200, 1,600, 2,000 rad, and 20,38, 57, $88\%$ by 5 fractionated irradiation of 1,400, 2,100, 2,800, 3,500 rad. $50\%$ tumor control dose$(TCD_{50})$ were 1,282rad, 2,312rad respectively with single and fractionated irradiation.

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Parameter Uncertainty and Sensitivity Analysis on a Dose Calculation Model for Terrestrial Food-Chain Pathway (육상식품 섭취경로에 의한 선량계산 모델에서 파라메터의 불확실성 및 민감도 분석)

  • Lee, Chang-Woo;Choi, Yong-Ho;Chun, Ki-Jung;Lee, Jeong-Ho
    • Journal of Radiation Protection and Research
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    • v.16 no.2
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    • pp.67-74
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    • 1991
  • Parameter uncertainty and sensitivity of KFOOD model for calculating the ingestion dose via terrestrial food-chain pathway was analyzed with using Monte-Carlo approach. For the rice ingestion pathway, estimated values from KFOOD code were very conservative. Most sensitive input parameters in model were deposition velocities and soil-to-plant transfer coefficient of radionuclides.

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A Study on the Assessment of Derived Intervention Levels in Foodstuffs Using the Dynamic Ingestion Pathway Model (동적 섭식경로모델을 이용한 음식물에 대한 유도 방사능 개입준위의 산정에 관한 연구)

  • Hwang, Won-Tae;Han, Moon-Hee;Kim, Byung-Woo
    • Journal of Radiation Protection and Research
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    • v.19 no.3
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    • pp.199-208
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    • 1994
  • The derived intervention levels in Korean foodstuffs were estimated using the dynamic ingestion pathway model which was developed considering Korean environment. The derived intervention levels were estimated from the intervention level of dose based on the thyroid committed dose equivalent of infant in the case of I-131, and the whole body committed dose equivalent for age groups and 13 kinds foodstuffs in the cases of Cs-137 and Sr-90. The derived intervention levels were shown as a considerable variation with deposition time and radionuclide. The adult was the most important age group in the estimation of derived intervention levels for Cs-137 and Sr-90. In the adult, the derived intervention levels for rice were 2390 and 47 Bq/kg for Cs-137 and Sr-90 in the case of deposition in summer, respectively, and 198 and 79 Bq/kg in the case of deposition in winter, respectively.

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Radiation-induced Pulmonary Damage in Lung Cancer Patients (폐종양 환자에서 방사선치료에 의한 폐손상)

  • Chung, Su-Mi;Choi, Ihl-Bohng;Kong, Ki-Hun;Kim, In-Ah;Shinn, Kyung-Sub
    • Radiation Oncology Journal
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    • v.11 no.2
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    • pp.321-330
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    • 1993
  • Purpose: A retrospective analysis was performed to evaluate the incidence of radiation induced lung damage after the radiation therapy for the patients with carcinoma of the lung. Method and Materials: Sixty-six patients with lung cancer (squamous cell carcinoma 27, adenocarcinoma 14, large cell carcinoma 2, small cell carcinoma 13, unknown 10) were treated with definitive, postoperative or palliative radiation therapy with or without chemotherapy between July 1987 and December 1991. There were 50 males and 16 females with median age of 63 years (range: 33~80 years). Total lung doses ranged from 500 to 6,660 cGy (median 3960 cGy) given in 2 to 38 fractions (median 20) over a range or 2 to 150 days (median in days) using 6 MV or 15 MV linear accelerator. To represent different fractionation schedules of equivalent biological effect, the estimated single dose (ED) model, $ED=D{\dot}N^{-0.377}{\dot}T^{-0.058}$ was used in which D was the lung dose in cGy, N was the number of fractions, and T was the overall treatment time in days. The range of ED was 370 to 1357. The endpoint was a visible increase in lung density within the irradiated volume on chest X-ray as observed independently by three diagnostic radiologists. Patients were grouped according to ED, treatment duration, treatment modality and age, and the percent incidence of pulmonary damage for each group was determined. Result: In 40 of 66 patients, radiation induced change was seen on chest radiographs between 11 days and 314 days after initiation of radiation therapy. The incidence of radiation pneumonitis was increased according to increased ED, which was statistically significant (p=0.001). Roentgenographic changes consistent with radiation pneumonitis were seen in $100\%$ of patients receiving radiotherapy after lobectomy or pneumonectomy, which was not statistically significant. In 32 patients who also received chemotherapy, there was no difference in the incidence of radiation induced change between the group with radiation alone and the group with radiation and chemotherapy, among the sequence of chemotherapy No correlation was seen between incidence of radiation pneumonitis and age or sex. Conclusions: The occurrence of radiation pneumonitis varies. The incidence of radiation pneumonitis depends on radiation total dose, nature of fractionation, duration of therapy, and modifying factors such as lobectomy or pneumonectomy.

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A Study of Radon Concentration in First Floor and Basement and Prediction of Annual Exposure Rate in Korea (국내 실내 라돈농도와 연간 피폭선량 예측에 관한 연구)

  • Lee, Jong-Dae;Kim, Yoon-Shin;Son, Bu-Soon;Kim, Dae-Seon
    • Journal of Environmental Science International
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    • v.15 no.4
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    • pp.311-317
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    • 2006
  • The purpose of this study was to investigate Rn concentration and annual radiation exposure level in the basement and first floor. The Rn Cup monitors were placed in different environments such as shopping stage, office building, Apartment, Hospital, house in Seoul from Match 1996 to April 1997 and CR-39 films were collected every two months. The mean radon concentration in the basement of house($88.6\;Bq/m^3$) showed the highest level among the areas, while radon concentration on the first floor of house($50.5\;Bq/m^3$) showed the higher than other areas. The annual radiation exposure dose that person on the floor / in the basement of differential place in the seoul can be exposed during living was estimated from 24.11 to 87.64 mRem/yr. This radiation dose is significantly lower than 130mRem maximum radiation dosage from the radon nuclide prescribed by the ICRP, with respect to the overall average exposure of the working adult. this study indicated that possible radon sources on the first floor / in the basement areas are radon intrusion from soil gas, construction materials, or ground water leaking. Further study is needed to quantitatively assess major contributions of radon-222 and health effect to radon exposure.

Decomposition of Antibiotics (Cefaclor) by Ionizing Radiation: Optimization and Modeling Using a Design of Experiment (DOE) Based on Statistical Analysis

  • Yu, Seung-Ho;Chang, Soon-Woong;Lee, Si-Jin;Cho, Il-Hyoung
    • Environmental Engineering Research
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    • v.14 no.2
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    • pp.81-87
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    • 2009
  • The decomposition of antibiotics (cefaclor) by gamma irradiation in aqueous solutions was experimentally evaluated. To obtain a mutual interaction between two factors (antibiotics concentrations and radiation doses) and to optimize these factors during the process, experimental design and statistical analysis were employed. The decomposition capability of the gamma radiation was also mathematically described as a function of cefaclor concentration and gamma-ray dose using the statistical analysis. The results showed that the cefaclor concentration ($X_1$) in the response $Y_1$ (Reduction of cefaclor concentration) and gamma-ray dose ($X_2$) in the response $Y_2$ (Removal efficiency (%) of cefaclor concentration) exhibited a significantly positive effect, whereas gamma-ray dose ($X_2$) in the response $Y_1$ showed a significantly negative effect. The estimated ridge of maximum responses and optimal conditions for $Y_1$:($X_1$,$X_2$)=(25 mg/L, 350 Gy) and $Y_2$:($X_1$,$X_2$)=(21 mg/L, 565 Gy) using canonical analysis were 4.37 mg/L of reduction of cefaclor concentration and 98.35% of removal efficiency of cefaclor concentration, respectively. The measurement values agreed well with the predicted ones, thereby confirming the suitability of the model for $Y_1$ and $Y_2$ and the success of the experimental design in optimizing the conditions of the gamma irradiation process.

Radiation dose and Lifetime Attributable Risk of Cancer Estimates in 64-slice Multidetector Computed Tomography (64-절편 다행검출 CT 검사에서의 환자선량과 암 발생의 Lifetime Attributable Risk(LAR) 평가)

  • Kang, Yeong-Han;Park, Jong-Sam
    • The Journal of the Korea Contents Association
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    • v.11 no.4
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    • pp.244-252
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    • 2011
  • This study was to estimate the radiation dose associated with 64-slice multidetector CT(MDCT) in clinical practice and quantify the potential cancer risk associated with these examinations. Lifetime attributable risks(LAR) were estimated with models developed in the national Academies' Biological Effects of Ionizing Radiation VII report. Mean effective dose were 1.48mSv in Brain axial scan, 7.66mSv in chest routine contrast, 12.17mSv in coronary angiogram, 24.52mSv in Dynamic abdomen scan. LAR estimates for brain routine varied from 1 in 7463 for man to 1 in 4926 for women. In chest routine with contrast, LAR varied from 1 in 1449 for men to 1 in 952. LAR of Abdomen dynamic CT varied from 1 in 453 for men to 1 in 298 for women. So, 64-slice MDCT scan is associated with non-negligible LAR of cancer. Doses can be reduced by careful attention to scanning protocol.

Dose Assessment in Accordance with the Measured Position of Size Specific Dose Estimates (Size Specific Dose Estimates(SSDE)측정 위치에 따른 피폭선량 평가)

  • Kim, Jung-Su;Hong, Sung-Wan;Kim, Jung-Min
    • Journal of radiological science and technology
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    • v.38 no.4
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    • pp.383-387
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    • 2015
  • This study investigated the size specific dose estimates of difference localizer on pediatric CT image. Seventy one cases of pediatric abdomen-pelvic CT (M:F=36:35) were included in this study. Anterior-posterior and lateral diameters were measured in axial CT images. Conversion factors from American Association of Physicists in Medicine (AAPM) report 204 were obtained for effective diameter to determine size specific dose estimate (SSDE) from the CT dose index volume (CTDIvol) recorded from the dose reports. For the localizer of mid-slice SSDE was 107.63% higher than CTDIvol and that of xiphoid-process slices SSDE was higher than 92.91%. The maximum error of iliac crest slices, xiphoid process slices and femur head slices between mid-slices were 7.48%, 17.81% and 14.04%. In conclusion, despite the SSDE of difference localizer has large number of errors, SSDE should be regarded as the primary evaluation tool of the patient radiation in pediatric CT for evaluation.