• Title/Summary/Keyword: Effective Dose Rate

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The Result of Radiation Therapy of Superior Vena Cava Syndrome (상행정맥 증후군의 방사선 치료 성적)

  • Cho Chong Hee;Kim Hyun Soon;Hong Seong Eon;Ahn Chi Yul
    • Radiation Oncology Journal
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    • v.4 no.1
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    • pp.67-73
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    • 1986
  • To access the result of radiation therapy for 8 years experiences, 21 patients who were treated with superior vena cava syndrome had been analysed according to dose fractionation and total dose. The results are as follows; 1. In high fractionate dose group, six of eleven patients $(54.5\%)$ exhibited relief of symptoms in 1-2 days, and additional three patients of nine $(81.7\%)$ within 34 days, while standard fractionated dose treatment is not effective to achieve initial relief of symptoms. 2. Graded response by total dose was correlated with total dose rather than dose fractionation. 3. Overall one year survival rate with superior vena cava syndrome was $9.1\%$ and mean survival was 4.2 months.

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Assessment of the Glycophorin A Mutant Assay as a Biologic Marker for Low Dose Radiation Exposure (저선량 방사선 노출에 대한 생물학적 지표로서 Glycophorin A 변이발현율 측정의 유용성 평가)

  • Ha, Mi-Na;Yoo, Keun-Young;Ha, Sung-Whan;Kim, Dong-Hyun;Cho, Soo-Hun
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.2
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    • pp.165-173
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    • 2000
  • Objectives : To assess the availability of the glycophorin A (GPA) assay to detect the biological effect of ionizing radiation in workers exposed to low-doses of radiation. Methods : Information on confounding factors, such as age and cigarette smoking was obtained on 144 nuclear power plant workers and 32 hospital workers, by a self-administered questionnaire. Information on physical exposure levels was obtained from the registries of radiation exposure monitoring and control at each facility. The GPA mutant assay was performed using the BR6 method with modification by using a FACScan flow cytometer. Results : As confounders, age and cigarette smoking habits showed increasing trends with GPA variants, but these were of no statistical significance. Hospital workers showed a higher frequency of the GPA variant than nuclear power plant workers in terms of the NO variant. Significant dose-response relationships were obtained from in simple and multiple linear regression models. The slope of the regression equation for nuclear power plant workers was much smaller than that of hospital workers. These findings suggest that there may be apparent dose-rate effects. Conclusion : In population exposed to chronic low-dose radiation, the GPA assay has a potential to be used as an effective biologic marker for assessing the bone marrow cumulative exposure dose.

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Radiosurgery for Recurrent Brain Metastases after Whole-Brain Radiotherapy : Factors Affecting Radiation-Induced Neurological Dysfunction

  • Gwak, Ho-Shin;Yoo, Hyung-Jun;Youn, Sang-Min;Lee, Dong-Han;Kim, Mi-Sook;Rhee, Chang-Hun
    • Journal of Korean Neurosurgical Society
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    • v.45 no.5
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    • pp.275-283
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    • 2009
  • Objective : We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction. Methods : In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was $12.4cm^3$. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria. Results : Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age(<60 years) and tumor volume affected survival rate(p=0.03, each). Acute (${\leq}$1 month) toxicity was observed in 22% of patients, subacute and chronic (>6 months) toxicity occurred in 21 %, respectively. Less acute toxicity was observed with small tumors (<$10cm^3$. p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gy${\times}cm^3$) was a significant predictor of both acute and chronic CNS toxicities. Conclusion: Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.

Distribution of X-ray Strength in Exposure Field Caused by Heel Effect (양극의 경사각 효과에 따른 조사야 X-선 강도 분포)

  • Jang, Keun-Jo;Kim, Nam-Hun;Lee, Jun-Haeng;Lee, Sang-Bock
    • Journal of the Korean Society of Radiology
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    • v.5 no.5
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    • pp.223-229
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    • 2011
  • When negative electron in x-ray tube is accelerated in to a high speed and then the currency of the electron is blocked by the target, x-ray happens by the conversion of the energy. The real area where the fast accelerated electron collides to a target area is called actual focal spot. When the string focused size is observed at the central ray side, where the direction x-ray comes out, the size seems to be reduced. This focus is called effective focal spot. According to radiation angle of x-rays tube, the degree of the negative pole side presents higher value than inclination, the amount of exposed radiation that patient receives differs by the angle of positive pole, which means effective focal spot is the variable. This paper presents the correlation between size of effective focal spot and amount of exposed radiation to the patient by it, and effective research for homogenized dose dispersion by the size of effective focal spot. In conclusion, following the focal size, effective range which was -8cm ~ 0 cm on average, was found and average dose rate was 0.019 R/min. Through this range, for patients with small radiation exposure, image with good density and resolution in aspect of diagnosing will be able to be obtained.

Efficacy of Bacteriophage Treatment in Murine Burn Wound Infection Induced by Klebsiella pneumoniae

  • Kumari, Seema;Harjai, Kusum;Chhibber, Sanjay
    • Journal of Microbiology and Biotechnology
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    • v.19 no.6
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    • pp.622-628
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    • 2009
  • In the present study, the therapeutic potential of purified and well-characterized bacteriophages was evaluated in thermally injured mice infected with Klebsiella pneumoniae B5055. The efficacy of five Klebsiella phages (Kpn5, Kpn12, Kpn13, Kpn17, and Kpn22) was evaluated on the basis of survival rate, decrease in bacterial counts in different organs of phage-treated animals, and regeneration of skin cells as observed by histopathological examination of phage-treated skin. Toxicity studies performed with all the phages showed them to be non-toxic, as no signs of morbidity and mortality were observed in phage-treated mice. The results of the study indicate that a single dose of phages, intraperitoneally (i.p.) at an MOI of 1.0, resulted in significant decrease in mortality, and this dose was found to be sufficient to completely cure K. pneumoniae infection in the burn wound model. Maximum decrease in bacterial counts in different organs was observed at 72 h post infection. Histopathological examination of skin of phage-treated mice showed complete recovery of burn infection. Kpn5 phage was found to be highly effective among all the phages and equally effective when compared with a cocktail of all the phages. From these results, it can be concluded that phage therapy may have the potential to be used as stand-alone therapy for K. pneumoniae induced burn wound infection, especially in situations where multiple antibiotic-resistant organisms are encountered.

The Comparison of Clinical Outcomes between GnRH Agonist Long Protocol and GnRH Antagonist Short Protocol in Oocyte Donation Cycles (난자공여를 통한 체외수정 시술에서 성선자극호르몬 유리호르몬 효능제 장기요법과 길항제 단기요법 사이의 임상 결과 비교)

  • Rhee, Jeong-Ho;Park, Joon-Chul;Kim, Jong-In
    • Clinical and Experimental Reproductive Medicine
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    • v.30 no.1
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    • pp.95-103
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    • 2003
  • Objective : To assess and compare the clinical outcomes between GnRH agonist long protocol and GnRH antagonist short protocol in oocyte donation program. Materials and Methods: Of total 18 oocyte donation cycles, controlled ovarian hyperstimulation (COH) were performed with GnRH agonist long protocol and GnRH antagonist short protocol in initial 9 cycles and later 9 cycles, respectively. Oral estradiol valerate and progesterone in oil we re administrated to all recipients for endometrial preparation. Oral estradiol administration was started from donor cycle day 1 after full shut down of gonadal axis with GnRH agonist in patients with ovarian function. Progesterone was injected from oocyte retrieval day of donor initially, then continuously till pregnancy 12 weeks if pregnancy was ongoing. We compared the parameters of clinical outcomes, such as number of the retrieved oocytes, fertilization rate, high grade embryo production rate, clinical pregnancy rate, implantation rate, ongoing pregnancy rate, COH duration, total gonadotropin dose for COH between GnRH agonist long protocol group and GnRH antagonist group. Statistical analysis was performed using Mann-Whitney test, p<0.05 was considered as statistically significant. Results: The number of retrieved oocytes, fertilization rate, high grade embryo production rate, clinical pregnancy rate, implantation rate, ongoing pregnancy rate were $14.89{\pm}7.83$, 81%, 64%, 78%, 31%, 78%, respectively in GnRHa long protocol group and $11.22{\pm}8.50$, 79%, 64%, 67%, 34%, 56%, respectively in GnRH antagonist group. There was no significant differences in parameters of clinical outcomes between 2 groups (all p value >0.05). Duration and total gonadotropin dose for COH were $10.94{\pm}1.70$ days and $43.78{\pm}6.8$ vials in 18 cycles, $12.00{\pm}1.73$ days and $48.00{\pm}6.93$ vials in agonist group, $9.88{\pm}0.78$ days and $39.55{\pm}3.13$ vials in antagonist group, respectively. In GnRH agonist long protocol group, significantly longer duration and higher gonadotropin dose for COH were needed (p=0.012). Conclusion: In oocyte donation program, clinical outcomes from controlled ovarian hyperstimulation with GnRH antagonist were comparable to those from GnRH agonist long protocol group, so controlled ovarian hyperstimulation with GnRH antagonist may be effective as GnRH agonist long protocol. At least there may not be harmful effects of GnRH antagonist on oocyte development and quality.

Antimutagenic Effect of Doenjang(Korean Fermented Soy Paste) toward Aflatoxin (된장의 Aflatoxin $B_1$에 대한 항돌연변이 효과)

  • 박건영;문숙희;백형석;최홍식
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.19 no.2
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    • pp.156-162
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    • 1990
  • Antimutagenic effect of doenjag (Korean fermented soy paste) on mutagenesis induced by aflatoxin B1 (AFB1) in Salmonella typhimurium strains TA98 and TA100 was studied. AFB1 revealed maximum mutagenicity at dose level of 1 $\mu$g/plate with metabolic activation system in both strains. Strong antiutagenic activity toward AFB1 was completely inhibited at the level of 50% of the doenjang extract. At the same concentration 64-66% and 39-53% of the AFB1 induced mutageneses were blocked when the methanol extracts of raw and cooked soybeans were added in the system respectively Raw soybeans showed higher ihhibition rate to the mutagenicity than cooked soybeans but the fermented soybeans(doenjang) was the most effective (p<0.05) Other soybean fermented foods such as commercial doenjang natto and miso were also exhibited some antimutagenic activities however the traditional doenjang was the most effective and then commercial doenjang. Natto and miso were less effective.

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Bisphenol-A Removal in Conventional Water Treatment Systems (정수처리공정에서 bisphenol-A의 제거에 관한 연구)

  • 김혜리;이윤진;박선구;남상호
    • Journal of Environmental Health Sciences
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    • v.30 no.1
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    • pp.59-64
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    • 2004
  • This study was carried out to investigate influencing factors of bisphenol A(BPA) removal characteristic in conventional water treatment systems to be connected with coagulation, sedimentation, filtration and disinfection. The result are summarized as follows; In BPA removal, optimal doses of PAC, alum, ferric chloride were 7.5 mg Al/L, 10.0 mg AI/L, 15.0 mg Fek. PAC was most effective coagulant to remove BPA. In coagulation process, BPA removal efficiency were increased about 2% by adjusting pH of raw water as 6. At temperature rise 1$0^{\circ}C$, BPA removal efficiency were increased 0.94%. but BPA removal efficiency in sand filtration process were under 1 %ie, so that BPA was almost not removed. At free chlorine dose 1, 2 mg/L, the reaction rate constant k in the BPA removal have been calculated to be 0.397, 0.953 min$^{-1}$ . At free chlorine dose 1, 2 mg/1-, degradation reaction of BPA was completed during 10 min and BFA removal efficiencies were 97.66, 99.99% at this time.

A Study on Structural Shielding Design of Afterloading Therapy Room (강내치료실 차폐에 대한 고찰)

  • Yun, Suk-Rok;Kim, Myung-Ho;Shin, Dong-Oh
    • The Journal of Korean Society for Radiation Therapy
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    • v.2 no.1
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    • pp.31-40
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    • 1987
  • In the case of designing a high dose rate remote controlled afterloading treatment room with existing hospital facilities. We must construct the effective protective barriers so as to reduce the primary and scattered radiation up to the maximum permissible dose level. It is difficult to reinforce the barrier thickness of the shielding requirements because of the limited space and the problem of the existing building structure at the surrounding area. Therefore we can reduce the intensity of primary radiation to the required degree at the location of interest with installing the appropriate I shaped Pb barriers between the radiation source and the shielding wall of the concrete. As a result, it was possible to reduce the intensity of the primary radiation below the M.P.D level by using additional Pb barriers instead of increasing thickness of concrete wall.

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The Confidence Band of $ED_{100p}$ for the Simple Logistic Regression Model

  • Cho, Tae Kyoung;Shin, Mi Young
    • Communications for Statistical Applications and Methods
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    • v.8 no.3
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    • pp.581-588
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    • 2001
  • The $ED_{100p}$ is that value of the dose associated with 100p% response rate in the analysis of quantal response data. Brand, Pinnock, and Jackson (1973) studied the confidence bands of $ED_{100p}$ obtained by solving extremal values algebraically on the ellipsoid confidence region of the parameters in the simple logistic regression model. In this paper, we develope and illustrate a simpler method for obtaining confidence bands for $ED_{100p}$ based on the rectangular confidence region of parameters.

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