• Title/Summary/Keyword: Target doses

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Establishment of micronuclus assay as biological dosimetry in pig lymphocytes after gamma-irradiation (돼지 림프구의 미소핵 형성을 지표로 방사선 생물학적 선량측정법 확립)

  • Kim, Se-ra;Lee, Hae-june;Lee, Jin-hee;Kang, Chang-mo;Kim, Tae-hwan;Jo, Sung-kee;Kim, Jong-choon;Kim, Sung-ho
    • Korean Journal of Veterinary Research
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    • v.44 no.3
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    • pp.323-327
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    • 2004
  • The purpose of the present experiment was to investigate the micronuclei(MN) frequency in cytokinesis-blocked(CB) cells after various doses of gamma-rays in pig (Landrace, male, 3-month-old) and so to contribute to the clarification of the question whether these species are suitable as a target organism in the test system. The frequencies of binucleated cells, and gamma-ray-induced MN in CB cells at several doses were measured in three donors. The peaks of binucleated lymphocyte formation(22%) were found at a concentration of 2% phytohaemagglutinin(PHA) and $4{\mu}g/ml$ Cytochalasin B(Cyt-B) in pig at 72 hours after incubation. Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. When analysed by linear-quadratic model the line of best fit was $y=0.0183D+0.0124D^2+0.0133$(y = number of MN/CB cells and D=irradiation dose in Gy). In conclusion, the results demonstrate that it appears feasible to use pig as target organisms in the micronucleus test to estimate the cytogenetic damage caused by ionizing radiations or, potentially, chemical compounds.

Iodine-131 S values for use in organ dose estimation of Korean patients in radioiodine therapy

  • Yeom, Yeon Soo;Shin, Bangho;Choi, Chansoo;Han, Haegin;Kim, Chan Hyeong
    • Nuclear Engineering and Technology
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    • v.54 no.2
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    • pp.689-700
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    • 2022
  • In the present study, iodine-131 S values (rT ← thyroid) were calculated for 30 target organs and tissues using the most recently developed Korean reference computational phantoms. The calculated S values were then compared with those of the International Commission on Radiological Protection (ICRP) reference computational phantoms to investigate the dosimetric impact of the Korean S values against those of the ICRP reference phantoms. The results showed significant differences in the S values due to the different anatomical/morphological characteristics between the Korean and ICRP reference phantoms. Most target organs/tissues showed that the S values of the Korean reference phantoms are lower than those of the ICRP reference phantoms, by up to about 4 times (male spleen and female thymus). Exceptionally, three target organs/tissues (gonads, thyroid, and extrathoracic region) showed that the S values of the Korean reference phantoms are greater, by 1.5-3.7 times. We expect that the S values calculated in the present study will be beneficially used to estimate organ/tissue doses of Korean patients under radioiodine therapy.

Comparison of plan dosimetry on multi-targeted lung radiotherapy: A phantom-based computational study using IMRT and VMAT

  • Khan, Muhammad Isa;Rehman, Jalil ur;Afzal, Muhammad;Chow, James C.L.
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3816-3823
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    • 2022
  • This work analyzed the dosimetric difference between the intensity modulated radiotherapy (IMRT), partial/single/double-arc volumetric modulated arc therapy (PA/SA/DA-VMAT) techniques in treatment planning for treating more than one target of lung cancer at different isocenters. IMRT and VMAT plans at different isocenters were created systematically using a Harold heterogeneous lung phantom. The conformity index (CI), homogeneity index (HI), gradient index (GI), dose-volume histogram and mean and maximum dose of the PTV were calculated and analyzed. Furthermore, the dose-volume histogram and mean and maximum doses of the OARs such as right lung, contralateral lung and non GTV were determined from the plans. The IMRT plans showed the superior target dose coverage, higher mean and maximum values than other VMAT techniques. PA-VMAT technique shows more lung sparing and DA-VMAT increases the V5/10/20 values of contralateral lung than other VMAT and IMRT techniques. The IMRT technique achieves highly conformal dose distribution to the target than other VMAT techniques. Comparing to the IMRT plans, the higher V5/10/20 and mean lung dose were observed in the contralateral lung in the DA-VMAT.

An Empirical Approach to Dosimetric Effect of Carbon Fiber Couch for Flattening Filter Free Beam of Elekta LINAC

  • Ahn, Sohyun;Park, Kwangwoo;Kim, Jinsung;Lee, Ho;Yoon, Jeongmin;Lee, Eungman;Park, Sohyun;Park, Jeongeun;Kim, Juhye;Keum, Ki Chang
    • Progress in Medical Physics
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    • v.27 no.4
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    • pp.220-223
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    • 2016
  • Generally, it is recommended that the dosimetric effect of carbon fiber couch should be considered especially for an intensity-modulated therapy with a large portion of monitor units from posterior angles. Even a flattening filter free (FFF) beam has been used for stereotactic body radiation therapy (SBRT), the effect of carbon fiber couch for FFF beam is not well known. This work is an effort to evaluate the dosimetric effect of carbon fiber couch for flattened and FFF beam of Elekta linac empirically. The absorbed doses were measured with Farmer type chamber and water-equivalent phantoms with and without couch. And differences of the absorbed doses between with and without couch defined as "couch effect". By comparing calculated dose in treatment planning system (TPS) with measured dose, the optimal density of couch was evaluated. Finally, differences on patient's skin dose and target dose by couch were evaluated in TPS. As a result, the couch effect for 6 and 10 MV flattened beam were -2.71% and -2.32%, respectively. These values were agreed with provided data by vendor within 0.5%. The couch effect for 6 and 10 MV FFF beam were -3.75% and -2.80%, respectively. The patient's skin dose was increased as 18.6% and target dose was decreased as 0.87%, respectively. It was realized that the couch effect of FFF beam was more severe than that of flattened beam. Patient's skin dose and target dose were changed by the couch effect.

Thirteen-week repeated-dose oral toxicity study of the Modified Wenpitang-Hab-Wulingsan (WHW$^{(R)}$) in Sprague-Dawley rats (WHW$^{(R)}$의 랫드에서의 반복경구투여 독성에 관한 연구)

  • Oh, Tae-Woo;Sang, Bae-Hyo;Yoon, Cheol-Ho;Park, Yong-Ki
    • The Korea Journal of Herbology
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    • v.25 no.3
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    • pp.43-51
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    • 2010
  • Objectives : We investigated the repeated-dose toxicity of Wenpitang-Hab-Wulingsan(WHW), a Korean traditional medicine prescribed with twelve herbs, which has been used for the treatment of renal disease. Methods : WHW extract prepared by GLP company. WHW was supplemented by gavage at 0, 100, 500 and 1000 mg/kg/day for 13-week consecutive days. We recorded the clinical signs of toxicity, body weight, organ weights, hematology, gross and histological changes in target organs rats and clinical chemistry analysis for all rats. Results : WHW extract at all doses was shown no mortality or abnormal clinical signs in rats during at the observation period. Furthermore, there was no difference in body weight and food-take consumption, organ weight, gross pathological findings, and urine analysis among the groups of rats treated with different doses of WHW extract. The hematological analysis and clinical blood chemistry data were revealed no toxic effects from WHW-treated rats. Conclusions : The results suggest that WHW extract in rats is a wide margin of safety on a acute toxicity.

Four-week Oral Toxicity Study of DA-9601, an Antiulcer Agent of Artemisia spp. Extract, in Rats (애엽추출물 항궤양제 DA-9601의 랫드에 대한 4주 경구 반복투여 독성연구)

  • 김옥진;강경구;김동환;백남기;안병옥;김원배;양중익
    • Biomolecules & Therapeutics
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    • v.4 no.4
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    • pp.354-363
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    • 1996
  • This study was conducted to investigate the repeated dose toxicity of DA-9601, an antiulcer agent of Artemisia app. extract, in rats. DA-9601 was administered orally once a day for 4 weeks to 10 males and 10 females per group at doses of 0(vehicle control), 125, 500 or 2000 mg/kg/day. Throughout the study, no treatment-related deaths and clinical signs were observed. In female rats receiving 125 mg/kg of DA-9601, water consumption increased slightly on day 4, 11 and 25. Hematological examination showed a decrease of MCV and an increase of PLT in male rats at the doses of 500 and 2000 mg/kg groups. Blood biochemistry revealed slight decreases of cholesterol, BUN and Na in male rats and decreases of total bilirubin and creatinine and slight increases of globulin and Cl in female rats. The organ weights at the end of 4 weeks showed slight changes in some organs of treated groups. But, all these changes were not considered to be of toxicological importance, because they did not show dose-response relationship and relevance to gross and microscopic findings. Histopathologically, abnormal treatment-related changes were not observed in any organ and target organs were not detected. On the basis of these results, the NOAEL(no-observed-adverse-effect level) of DA-9601 was estimated to be more than 2000 mg/kg/day under the conditions tested.

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Study on the inactivation of intracellular enzyme mlecules by X-ray irradiation (X-선조사(線照射)에 의한 세포내효소분자(細胞內酵素分子)의 불활성화(不活性化)에 관한 연구(硏究))

  • Lee, Sang-Bok
    • Journal of Radiation Protection and Research
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    • v.2 no.1
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    • pp.31-37
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    • 1977
  • Inactivation of the glutamic acid dehydrogenase and glucose-6-phosphate dehydrogenase enzyme-molecules in the Ehrlich ascites tumor cells of the mouse were studied. The above mentioned intracellular enzymemolecules were irradiated by the X-ray radiation under the condition of 65 kV, I Amp. under the atmosphere of nitrogen gases and by $4^{\circ}C$. Thereby, irradiation doses were 580 KR/min($error:{\pm}3%$). After irradiation, the cell homogentes were prepared through liquid air techniquese. There after, the activities of the enzymes were measured with photometric method given by O. Warburg and W. Christian. The dose effect curves of the activities of the two enzymes by the X-ray irradiation showed both exponential and the inactivation doses were $6,5.10^{0}\;and\;5,0.10^{6}$ R respectively. These results showed one side that the inactivation process of the intracelluar enzymemolecules was one hit reaction after target theory, and the other side that this inactivation process could not be the primary causes of the death through X-ray irradiation of the vertebrate animals, because of the high resistance of the intracellular protein molecules against X-ray irradiation. The one hit reaction by the inactivation process of the irradiated intracellular enzymemolecules was discussed.

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Disruption of Established Bacterial and Fungal Biofilms by a Blend of Enzymes and Botanical Extracts

  • Gitte S. Jensen;Dina Cruickshank;Debby E. Hamilton
    • Journal of Microbiology and Biotechnology
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    • v.33 no.6
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    • pp.715-723
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    • 2023
  • Microbial biofilms are resilient, immune-evasive, often antibiotic-resistant health challenges, and increasingly the target for research into novel therapeutic strategies. We evaluated the effects of a nutraceutical enzyme and botanical blend (NEBB) on established biofilm. Five microbial strains with known implications in chronic human illnesses were tested: Candida albicans, Staphylococcus aureus, Staphylococcus simulans (coagulase-negative, penicillin-resistant), Borrelia burgdorferi, and Pseudomonas aeruginosa. The strains were allowed to form biofilm in vitro. Biofilm cultures were treated with NEBB containing enzymes targeted at lipids, proteins, and sugars, also containing the mucolytic compound N-acetyl cysteine, along with antimicrobial extracts from cranberry, berberine, rosemary, and peppermint. The post-treatment biofilm mass was evaluated by crystal-violet staining, and metabolic activity was measured using the MTT assay. Average biofilm mass and metabolic activity for NEBB-treated biofilms were compared to the average of untreated control cultures. Treatment of established biofilm with NEBB resulted in biofilm-disruption, involving significant reductions in biofilm mass and metabolic activity for Candida and both Staphylococcus species. For B. burgdorferi, we observed reduced biofilm mass, but the remaining residual biofilm showed a mild increase in metabolic activity, suggesting a shift from metabolically quiescent, treatment-resistant persister forms of B. burgdorferi to a more active form, potentially more recognizable by the host immune system. For P. aeruginosa, low doses of NEBB significantly reduced biofilm mass and metabolic activity while higher doses of NEBB increased biofilm mass and metabolic activity. The results suggest that targeted nutraceutical support may help disrupt biofilm communities, offering new facets for integrative combinational treatment strategies.

Four-week Oral Toxicity Study of DA-5018, a New non-narcotic Analgesic Agent (비 마약성 진통제 DA-5018의 랫드에 대한 4주 경구투여 아급성독성)

  • 강경구;김옥진;백남기;안병옥;김원배;양중익
    • Biomolecules & Therapeutics
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    • v.5 no.2
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    • pp.133-149
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    • 1997
  • 4-week repeated dose toxicity of DA-5018, a new capsaicin analogue analgesic agent, was examined in 5D rats at dosage levels of 0,0.4,2, 10 and 50 mg/kg/day. DA-5018 was administered orally to 17 males and 17 females per group at doses of 0, 10 and 50 mg/kg and to 12 males and 12 females per group at doses of 0.4 and 2 mg/kg. After the administration period, 5 males and 5 females at the 0, 10 and 50 mg/kg were placed on withdrawal for 2 weeks. Treatment-related clinical signs were observed at 10 and 50 mg/kg. Clinical signs observed immediately after the administration of DA-5018 were grooming, sedation or depression, lacrimation, atacia, reddening of extremities and ears, ventral or lateral recumvincy, respiratory distress, cyanosis and convulsion. Delayed-type clinical signs including focal scabbing and depilation around nose were also observed 1 or 2 weeks after the start of administration of DA-5018. Only at the 50 mg/kg group, corneal opacities, reduced body weight gain (male) and death (male 6/17, female 3/17) were noted. In blood biochemical analysis, serum levels of glucose and triglyceride decreased at 10 and 50 mg/kg. In hematological examination, there were increases in the number of red blood cell, hemoglobin content and percent of hematocrit at 10 and 50 mg/kg. Pulmonary enlargement and hemorrhagic spot, focal scabbing and depilation around nose and corneal opacities were seen at the necropsy of the animals died during the dosing of DA-5018 50 mg/kg. Focal scabbing and depilation around nose were observed in the animals terminally necropsied at doses of 10 and 50 mg/kg. Histopathological examination revealed pulmonary hemorrhage, focal necrosis in the scabbed area, corneal necrosis, fibrosis and neovasculization in the stroma. At 0.4 and 2 mg/kg, there were no significant toxic changes attributable to the administration of DA-5018. In conclusion, target organs following to 4-week repeated dose of DA-5018 in the rat were determined to be lung, skin and eyes. Definite toxic dose and no-observed-adverse-effect-level (NOAEL) were estimated to be 50 and 2 mg/kg/day, respectively.

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Liver dose reduction by deep inspiration breath hold technique in right-sided breast irradiation

  • Haji, Gunel;Nabizade, Ulviye;Kazimov, Kamal;Guliyeva, Naile;Isayev, Isa
    • Radiation Oncology Journal
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    • v.37 no.4
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    • pp.254-258
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    • 2019
  • Purpose: Deep inspiration breath hold (DIBH) is a well-established technique that enables efficient cardiac sparing in patients with left-sided breast cancer. The aim of the current study was to determine if DIBH is effective for reducing radiation exposure of of liver and other organs at risk in right breast radiotherapy (RT). Materials and Methods: Twenty patients with right-sided breast cancer were enrolled in this study. Three-dimensional conformal RT plans were generated for each patient, with two different computed tomography scans of free breathing (FB) and DIBH. Nodes were contoured according to the Radiation Therapy Oncology Group contouring guidelines. Dose-volume histograms for the target volume coverage and organs at risk were evaluated and analyzed. Results: DIBH plans showed significant reduction in mean liver dose (5.59 ± 2.07 Gy vs. 2.54 ± 1.40 Gy; p = 0.0003), V20Gy (148.38 ± 73.05 vs. 64.19 ± 51.07 mL; p = 0.0003) and V10Gy (195.34 ± 93.57 vs. 89.81 ± 57.28 mL; p = 0.0003) volumes compared with FB plans. Right lung doses were also significantly reduced in DIBH plans. Heart and left lung doses showed small but statistically significant improvement with application of the DIBH technique. Conclusion: We report that the use of DIBH for right-sided breast cancer significantly reduces the radiation doses to the liver, lungs, and heart.