• Title/Summary/Keyword: Dose rate assessment

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Validation of a Rodent Nose-only Exposure System for Inhalation Toxicity Evaluation of Cigarette Smoke (담배 흡입독성 평가를 위한 설치류 담배연기노출시스템의 유효화)

  • Sohn, Hyung-Ok;Lee, Hyeong-Seok;Shin, Han-Jae;Park, Chul-Hoon;Yoo, Ji-Hye;Jang, Mi;Hyun, Hak-Chul
    • Journal of the Korean Society of Tobacco Science
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    • v.36 no.1
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    • pp.20-25
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    • 2014
  • As part of a balanced testing battery, subchronic inhalation studies on rats are performed to ensure that proposed cigarette modifications do not increase the toxicity of smoke and to demonstrate any instances where a modification may actually contribute to harm reduction. For subchronic inhalation studies with aerosols, the OECD suggests an exposure regimen of 6 hours/day (OECD Guideline 413, 1981), but alternative regimens have also been published: 1 hour/day and $2{\times}1$ hour/day. The aim of this study was to validate a rodent nose-only exposure system for the assessment of inhalation toxicity of cigarette smoke. In this study, cigarette smoke exposure system is consisted of cigarette smoke generator, smoke concentration adjusting system, and 20-port nose-only exposure system. Male SD rats were exposed for 35 days ($2{\times}1$ hour/day) to 3R4F Reference cigarette smoke and analysed major monitoring items of OECD Gudeline 413. WTPM, was measured in the test atmosphere, respiratory function (Buxco Biosystems) during exposure, postexposure urinary exposure biomarkers and alveolar neutrophiles in BAL fluid (Day 35) were evaluated. Validation demonstrated steady WTPM ($257{\pm}20ug/L$, $502{\pm}27ug/L$) and spatial uniformity (<10%). Nose port temperature ($22{\sim}26^{\circ}C$ and RH (45~75%) were acceptable over 35 days. Reductions in respiratory rate and minute volume and increase in the neutrophiles in BALF and the urinary exposure biomarkers were observed cigarette smoke dose dependently. This validation and 35-day inhalation study has shown that the rodent nose-only exposure system may be useful in the inhalation toxicity assessment of cigarette smoke.

Radiological Impact Assessment for the Domestic On-road Transportation of Radioactive Isotope Wastes (방사성동위원소 폐기물의 국내육상운반에 관한 방사선영향 평가)

  • Seo, Myunghwan;Hong, Sung-Wook;Park, Jin Beak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.14 no.3
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    • pp.279-287
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    • 2016
  • Korea Radioactive Waste Agency (KORAD) began to operate the low and intermediate level radioactive waste disposal facility in Gyeongju and to transport the radioactive waste containing radioactive isotopes from Daejeon to the disposal facility for the first time at 2015. For this radioactive waste transportation, in this study, radiological impact assessment is carried out for workers and public. The dose rate to workers and public during the transportation is estimated with consideration of the transportation scenarios and is compared with the Korean regulatory limit. The sensitivity analysis is carried out by considering both the variation of release ratios of the radioactive isotopes from the waste and the variation of the distances between the radioactive waste drum and worker during loading and unloading of radioactive waste. As for all the transportation scenarios, radiological impacts for workers and public have met the regulatory limits.

Therapeutic Assessment of Primaquine for Radical Cure of Plasmodium vivax Malaria at Primary and Tertiary Care Centres in Southwestern India

  • Kumar, Rishikesh;Guddattu, Vasudeva;Saravu, Kavitha
    • Parasites, Hosts and Diseases
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    • v.54 no.6
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    • pp.733-742
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    • 2016
  • Acquaintance is scanty on primaquine (PQ) efficacy and Plasmodium vivax recurrence in Udupi district, Karnataka, India. We assessed the efficacy of 14 days PQ regimen (0.25 mg/kg/day) to prevent P. vivax recurrence. Microscopically, aparasitemic adults (${\geq}18years$) after acute vivax malaria on day 28 were re-enrolled into 15 months' long follow-up study. A peripheral blood smear examination was performed with participants at every 1-2 month interval. A nested PCR test was performed to confirm the mono-infection with P. vivax. Of 114 participants, 28 (24.6%) recurred subsequently. The median (IQR) duration of the first recurrence was 3.1 (2.2-5.8) months which ranged from 1.2 to 15.1 months, including initial 28 days. Participants with history of vivax malaria had significantly higher risk of recurrence, with hazard ratio (HR) (95% CI) of 2.62 (1.24-5.54) (P=0.012). Severity of disease (11.4%, 13/114) was not associated (P=1.00) with recurrence. Of 28 recurrence cases, the nPCR proved that P. vivax mono-infection recurrence rate was at least 72.7% (16/22) at first recurrence. In Udupi district, PQ dose of 0.25 mg/kg/day over 14 days seems inadequate to prevent recurrence in substantial proportion of vivax malaria. Patients with a history of vivax malaria are at high risk of recurrences.

Assessment of Lymph Node Metastasis of the Stomach Cancer by Tc 99m Phytate Lymphoscintigraphy ($Tc^{99m}$ phytate를 이용한 위암의 임파절 영상)

  • Yoo, Hyung-Sik;Lee, Jong-Tae;Park, Chang-Yun;Min, Jin-Sik;Kim, Choong-Bai
    • The Korean Journal of Nuclear Medicine
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    • v.19 no.2
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    • pp.51-55
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    • 1985
  • Prospective study of lymph node imaging of twenty stomach cancer cases with dissected lymph nodes being injected into the submucosa layer of stomach under surgical field was done. Total dose of 5 mci in 5 cc of volume was injected along the multiple sites of the lesser and greater curvature of stomach and collected lymph nodes within 2 hour of surgical time were placed under gamma camera and lymph node imagings were obtained. Pathological invasion of tumor and correlation of cold defect or hot uptake was compared each other. Tumor invasion of nodes revealed cold defect area which was correlated well with the pathological specimen. Correlation rate was 84.6%. We are planning to extend these procedures and trying endoscopic injection of positive imgaing agents such as Ga-73-3 Ig 2 alpha in future.

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Folate Status in Pregnant and Lactating Women (임신기와 수유기의 엽산 영양)

  • 임현숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.5
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    • pp.983-992
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    • 1997
  • During pregnancy and lactation, folate status is important because folate requirements increase during the periods as well as maternal folate status influences on pregnancy outcome and human milk folate; especially folate deficiency around periconceptional period may induce neural tube defects(NTDs) of fetus. There have been a plenty of evidences that maternal folate status deteriorates during pregnancy of fetus. There have been a plenty of evidences that maternal folate status deteriorates during pregnancy and lactation if folate needed is not sufficiently provided. The Public health Service of the United States recommends all child-bearing is not sufficiently provided. The Public Health Service of the United States recommends all child-bearing women to intake 0.4mg of folate daily, and the Food and Drug Administration the folate status of child-bearing women and to reduce the rate of occurrence of NTDs. Many authors have insisted that the current recommended dietary allowances of folate for Americans are too low to maintain good folate status. There are little data about Korean folate status including pregant and lactating women. A couple of reports indicated that the folate intakes of Korean pregant and lactating women are below the Korean RDAs of folate and serum folate levels of them are subnormal. The authors pregnant and lactating women. Therefore, it is worth to review the assessment methods of folate status of pregnant and lactating women, folate RDAs for them, the relationships between maternal folate status and pregnancy outcome as well as human milk folate, the methods to increase folate intake, and the problems of large dose of folic acid supplementatiion.

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The Efficacy of Moxibustion for Female Stress Urinary Incontinence: a Systematic Review (여성 복압성 요실금에 대한 뜸 치료의 효과 : 체계적 문헌 고찰)

  • Park, Hye-Rin;Jo, Hee-Geun
    • The Journal of Korean Obstetrics and Gynecology
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    • v.33 no.4
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    • pp.1-22
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    • 2020
  • Objectives: The purpose of this review is to evaluate the efficacy of moxibustion for stress urinary incontinence (SUI) in women. Methods: For relevant randomized controlled trials (RCTs), we searched the following databases from their inception to September 1, 2020: The Cochrane Library, PubMed, EMBASE, Chinese National Knowledge Infrastructure Database (CNKI), Koreanstudies Information Service System (KISS), Research Information Sharing Service (RISS), and National Digital Science Library (NDSL). The key search terms were 'stress urinary incontinence' and 'moxibustion'. Data extraction and assessment of risk of bias were conducted by two authors independently. Results: A total of 11 RCTs were finally included in this systematic review. In all studies, moxibustion treatment was applied as an adjuvant therapy to the conventional treatment, and the most common conventional treatment was pelvic floor muscle training (PFMT). The treatment group (conventional treatment plus moxibustion) showed statistically more significant effect than the control group (conventional treatment only) in various evaluation indicators including urinary incontinence frequency, 1 hour urine pad test, quality of life, the clinical efficacy rate, and pelvic muscle strength. Conclusions: In this study, we investigated the efficacy of moxibustion as an adjuvant therapy for female SUI patients. Further studies are needed to supplement the safety of moxibustion and the evaluation of moxibustion dose.

The study of Breast Specific Gamma Imaging Protocol using Self-development Phantom (자체 제작된 팬텀을 적용한 Breast Specific Gamma Imaging 검사 프로토콜에 대한 고찰)

  • Lee, Hae-Jung;Lee, Juyoung;Lim, Kuen-Kyo;Park, Hoon-Hee
    • The Korean Journal of Nuclear Medicine Technology
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    • v.18 no.2
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    • pp.39-47
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    • 2014
  • Purpose As breast cancer patients continue to increase every year, cases of BSGI are on the rise with a heavier reliance on it. However, BSGI protocol in hospitals was not studied enough despite it was covered by hospital's condition and recommendation of manufacturers. The objective of the study was an examination of methods to be applicable to BSGI protocols, putting the self-development phantom to use in quality assessment of the images. Materials and Methods Dilon 6800 (Dilon Technologies Inc, Newport News, USA) was used in the study and five different sizes of sphere were distinctively produced in the phantom. The study used $^{99m}TcO_4$. The cases were classified in to three categories that background radioactivity to region of interest as ratio of 2: 4: 8, They were acquired images for 5, 7, 10mins. The acquired image was set region of interest according to the size of sphere, and We analyzed quantitative and qualitative analysis. The acquired data statistically analyzed with SPSS ver.18.0. Results As the result of quantitative and qualitative analysis, count rate of each sphere in accordance with difference of injection dose showed that higher count rate as injection dose and sphere size increased (P<0.005). Count rate of each sphere in accordance with difference of acquisition time showed that higher count rate as acquisition time and sphere size increased (P<0.005). Contrast noise ratio of each sphere in accordance with difference of injection dose showed that higher contrast noise ratio as injection dose increased. Particularly, Contrast noise ratio of eight times ratio images was the highest among. Contrast noise ratio of each sphere in accordance with difference of acquisition time showed that higher contrast noise ratio as acquisition time increased. And, Contrast noise ratio of seven minute image was the highest among (P<0.005). Conclusion There was significant change of Contrast noise ratio through quantitative and qualitative analysis. Moreover, We found usefulness of phantom. If Institutions identified image through the phantom study and they made BSGI protocol, We expected to help the improvement of diagnostic value of the images.

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Image Evaluation and Exposure Dose with the Application of Tube Voltage and Adaptive Statistical Iterative Reconstruction of Low Dose Computed Tomography (저 선량 전산화단층촬영의 관전압과 적응식 통계적 반복 재구성법 적용에 따른 영상평가 및 피폭선량)

  • Moon, Tae-Joon;Kim, Ki-Jeong;Lee, Hye-Nam
    • Journal of radiological science and technology
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    • v.40 no.2
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    • pp.261-267
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    • 2017
  • The study has attempted to evaluate and compare the image evaluation and exposure dose by respectively applying filter back projection (FBP), the existing test method, and adaptive statistical iterative reconstruction (ASIR) with different values of tube voltage during the low dose computed tomography (LDCT). With the image reconstruction method as basis, chest phantom was utilized with the FBP and ASIR set at 10%, 20% respectively, and the change of tube voltage (100 kVp, 120 kVp). For image evaluation, back ground noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were measured, and, for dose assessment, CTDIvol and DLP were measured respectively. In terms of image evaluation, there was significant difference in ascending aorta (AA) SNR and inpraspinatus muscle (IM) SNR with the different amount of tube voltage (p < 0.05). In terms of CTDIvol, the measured values with the same tube voltage of 120 kVp were 2.6 mGy with no-ASIR and 2.17 mGy with 20%-ASIR respectively, decreased by 0.43 mGy, and the values with 100 kVp were 1.61 mGy with no-ASIR and 1.34 mGy with 20%-ASIR, decreased by 0.27 mGy. In terms of DLP, the measured values with 120 kVp were $103.21mGy{\cdot}cm$ with no-ASIR and $85.94mGy{\cdot}cm$ with 20%-ASIR, decreased by $17.27mGy{\cdot}cm$ (about 16.7%), and the values with 100 kVp were $63.84mGy{\cdot}cm$ with no-ASIR and $53.25mGy{\cdot}cm$ with 20%-ASIR, a decrease by $10.62mGy{\cdot}cm$ (about 16.7%). At lower tube voltage, the rate of dose significantly decreased, but the negative effects on image evaluation was shown due to the increase of noise.

The Usefulness Assessment of Verifying Daily Output by Using CHECKMATE$^{TM}$ (CHECKMATE$^{TM}$를 이용한 일일 출력 검증의 유용성 평가)

  • Cho, Han-Sang;Nam, Sang-Soo;Park, Hae-Jin;Kim, Mi-Hwa;Park, An-Tae
    • The Journal of Korean Society for Radiation Therapy
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    • v.23 no.1
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    • pp.51-58
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    • 2011
  • Purpose: In this study, we tried to check the usefulness of two Linear Accelerators, Clinac IX and 21EX (Varian, Palo Alto, CA), which are equipped in Ajou Medical Center. From 2008 to 2010, we evaluated the error range of Absolute Dose based on the daily output, which was measured by CHECKMATE$^{TM}$ (Sun Nuclear, Melbourne, FL). Materials and Methods: For Daily Q.A, photon beams of two linear accelerators, 21EX and IX (6 MV and 10 MV, respectively) were measured daily by using CHECKMATE$^{TM}$ just before the treatment began, while the absolute dose was measured biweekly by using water phantom. We analyzed the data of measured values from the daily Q.A and the absolute dose from 2008 to 2010 for 21EX, and from 2009 to 2010 for IX. We utilized Excel 2007 (Microsoft, USA) to evaluate Average, Standard deviation and Confidence level of the data. Furthermore, in order to check the measured values of CHECKMATE$^{TM}$ and the significance of absolute dose, each error value was compared and analyzed. Results: During the observation period, the output of two equipment's absolute dose increased in process of time and in both 6 MV and 10 MV, there was a similar increasing trend. In addition, the error rate of the measured value of CHECKMATE$^{TM}$ and the value of absolute dose were under 0.34, which means that there is a similarity relationship between the two measured values. After checking that the measured value of CHECKMATE$^{TM}$ increased, We measured the absolute dose to adjust that. When the error range was close to 2~3%, the number of changing the output was four for 21EX and three for IX. Conclusion: As a result of measuring and analyzing the daily output changes for two years by using CHECKMATE$^{TM}$, we could find that there is a significance between the output which we should obey during Q.A, and the measured value of absolute dose within the error tolerance of 2~3%. Thus, the use of CHECKMATE$^{TM}$ can be positively considered for more efficient and reliable daily output verification of linear accelerator. It can also be a good standard for other medical centers to understand the trends of linear accelerator and to refer to for the correction of each output.

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A Study on $^{99m}Tc$-pertechnetate thyroid uptake in various thyroid diseases (각종(各種) 갑상선질환(甲狀腺疾患)의 $^{99m}Tc$-pertechnetate 갑상선섭취(甲狀腺攝取)에 관(關)한 연구(硏究))

  • Choi, Sung-Jae;Min, Hae-Sook;Koh, Chang-Soon;Lee, Mun-Ho
    • The Korean Journal of Nuclear Medicine
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    • v.8 no.1_2
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    • pp.29-37
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    • 1974
  • The $^{99m}Tc$-pertechnetate thyroid uptake rates(20 min) were measured in 24 healthy normal subjects, 140 patients with nontoxic goiter and 98 patients with thyrotoxicosis who were treated at the Thyroid Clinic, Seoul National University Hospital, from August 1972 to August 1973. Diagnostic reliabilities and correlations between $^{99m}TcO_4$-thyroid uptake rate (20 min) and other thyroid function tests were evaluated. The observed results were as follows 1. The $^{99m}TcO_4$-thyroid uptake rates (20 min) in normal subjects, euthyroid group and hyperthyroid group were $4.1{\pm}0.9%,\;5.2{\pm}1.8%\;and\;29.7{\pm}10.6%$. There was a significant difference between the mean of the euthyroid group and the mean of the hyperthyroid group and so differentiation between them can be easy. 2. In the diagnosis of hyperthyroidism, the reliabilities of $^{99m}TcO_4$- thyroid uptake rate(20 min), $^{131}I$ thyroid uptake rate(24hrs), serum $T_3$ resin uptake rate, serum $T_4\;and\;T_7\;were\;87.9{\sim}97.9%,\;81.2{\sim}94.4%,\;87.9{\sim}97.9%,\;90.5{\sim}99.3%\;and\;93.7{\sim}100%$. $^{99m}TcO_4$-thyroid uptake rate(20 min) is more accurate than $^{131}I$ thyroid uptake rate (24 hrs) in the diagnosis of hyperthyroidism. 3. $^{99m}TcO_4$-thyroid uptake rate (20 min) was well correlated with $^{131}I$ thyroid uptake rate (24 hrs), serum $T_3$ resin uptake rate, serum $T_4\;and\;T_7$. Points in favor of $^{99m}Tc$ are that it gives a small radiation dose to the thyroid, that tests can be repeated at the short interval, the study can be completed at a single patient visit and it is particularly well suited for the assessment of thyroid function in patients being treated with an antithyroid drug.

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