• 제목/요약/키워드: Radiation tolerance

검색결과 195건 처리시간 0.029초

Long-term tolerance and outcomes for dose escalation in early salvage post-prostatectomy radiation therapy

  • Safdieh, Joseph J.;Schwartz, David;Weiner, Joseph;Weiss, Jeffrey P.;Rineer, Justin;Madeb, Isaac;Rotman, Marvin;Schreiber, David
    • Radiation Oncology Journal
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    • 제32권3호
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    • pp.179-186
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    • 2014
  • Purpose: To study the long-term outcomes and tolerance in our patients who received dose escalated radiotherapy in the early salvage post-prostatectomy setting. Materials and Methods: The medical records of 54 consecutive patients who underwent radical prostatectomy subsequently followed by salvage radiation therapy (SRT) to the prostate bed between 2003-2010 were analyzed. Patients included were required to have a pre-radiation prostate specific antigen level (PSA) of 2 ng/mL or less. The median SRT dose was 70.2 Gy. Biochemical failure after salvage radiation was defined as a PSA level >0.2 ng/mL. Biochemical control and survival endpoints were analyzed using the Kaplan-Meier method. Univariate and multivariate Cox regression analysis were used to identify the potential impact of confounding factors on outcomes. Results: The median pre-SRT PSA was 0.45 ng/mL and the median follow-up time was 71 months. The 4- and 7-year actuarial biochemical control rates were 75.7% and 63.2%, respectively. The actuarial 4- and 7-year distant metastasis-free survival was 93.7% and 87.0%, respectively, and the actuarial 7-year prostate cancer specific survival was 94.9%. Grade 3 late genitourinary toxicity developed in 14 patients (25.9%), while grade 4 late genitourinary toxicity developed in 2 patients (3.7%). Grade 3 late gastrointestinal toxicity developed in 1 patient (1.9%), and grade 4 late gastrointestinal toxicity developed in 1 patient (1.9%). Conclusion: In this series with long-term follow-up, early SRT provided outcomes and toxicity profiles similar to those reported from the three major randomized trials studying adjuvant radiation therapy.

Selection and Genetic Relationship of Salt Tolerant Rice Mutants by in vitro Mutagenesis

  • Song, Jae Young;Kim, Dong Sub;Lee, Myung-Chul;Lee, Kyung Jun;Kim, Jin-Baek;Kim, Sang Hoon;Yun, Song Joong;Kang, Si-Yong
    • 방사선산업학회지
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    • 제4권4호
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    • pp.307-312
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    • 2010
  • Plants have evolved physiological, biochemical and metabolic mechanisms to increase their survival under the adverse conditions. This present study has been performed to select salt-tolerant rice mutant lines through in vivo and in vitro mutagenesis with gamma-rays. For the selection of the salt-tolerant rice mutants, we conducted three times of selection procedure using 1,500 gamma ray mutant lines resulted from an embryo culture of the original rice cv. Dongan (wild-type, WT): first, selection in the a nutrient solution with 171 mM NaCl; second, selection under in vitro condition with 171 mM NaCl; and third, selection in a reclaimed saline land. Based on a growth comparison of the entries, out of the mutant lines, two putative 2 salt tolerant (ST) rice mutant lines, ST-87 and ST-301, were finally selected. The survival rate of the WT, ST-87 and ST-301 were 36.6%, 60% and 66.3% after 7 days in 171 mM NaCl treatment, respectively. The WT and two salt tolerant mutant lines were used to analyze their genetic variations. A total of 21 EcoRI and Msel primer combinations were used to analyze the genetic relationship of among the two salt-tolerant lines and the WT using the ABI3130 capillary electrophoresis system. In the AFLP analysis, a total of 1469 bands were produced by the 21 primer combinations, and 700 (47.6%) of them were identified as having polymorphism. The genetic similarity coefficients were ranged from 0.52 between the ST-87 and WT to 0.24 between the ST-301 and the WT. These rice mutant lines will be used as a control plot for physiological analysis and genetic research on salt tolerance.

방사선치료계획 정도관리 방법에 따른 신뢰도 평가 (Reliability estimation about quality assurance method of radiotherapy planning)

  • 김정호;김가중;유세종;김기진
    • 대한안전경영과학회지
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    • 제17권1호
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    • pp.119-124
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    • 2015
  • According as radiation therapy technique develops, standardization of radiation therapy has been complicated by the plan QA(Quality Assurance). However, plan QA tools are two type, OADT (opposite accumulation dose tool) and 3DADT (3 dimensional accumulation dose tool). OADT is not applied to evaluation of beam path. Therefore tolerance error of beam path will establish measurement value at OADT. Plan is six beam path, five irradiation field at each beam path. And beam path error is 0 degree, 0.2 degree, 0.4 degree, 0.6 degree, 0.6 degree, 0.8 degree. Plan QA accomplishes at OADT, 3DADT. The more path error increases, the more plan QA error increases. Tolerance error of OADT path is 0.357 using tolerance error of conventional plan QA. Henceforth plan QA using OADT will include beam path error. In addition, It will increase reliability through precise and various plan technique.

UV-A LED을 이용한 고추 묘의 저온 내성 유도 (Elicitation of Chilling Tolerance of Pepper Seedlings Using UV-A LED)

  • 박송이
    • 한국환경농학회지
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    • 제39권3호
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    • pp.273-279
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    • 2020
  • BACKGROUND: After transplanting, the recent abnormal low temperature caused physiological disorders of pepper seedlings. This study was conducted to evaluate the effects of UV-A LED, a physical elicitor, on the chilling tolerance of pepper seedlings. METHODS AND RESULTS: Seedlings were continuously irradiated with 370 and 385 nm UV-A LEDs with 30 W·m-2 for 6 d. After that, seedlings were exposed to 4℃ for 6 h and then recovered under the normal growing condition for 2 d. There were no significant differences in growth characteristics of UV-A treatments compared to the control. Fv/Fm values of two UV-A treatments were below 0.8. Electrolyte leakage in the control was increased by chilling stress, while 385 nm UV-A had the significantly lowest value. Total phenolic content and antioxidant capacity of two UV-A treatments significantly increased due to UV-A radiation. However, total phenolic content and antioxidant capacity of the control increased due to chilling stress and tended to decrease again during the recovery time. CONCLUSION: We confirmed that UV-A light was effective to induce the chilling tolerance of pepper seedling, and the supplemental radiation of 385 nm UV-A LED before transplanting could be used as a cultivation technique to produce high quality pepper seedlings.

Enhancement of the Chaperone Activity of Alkyl Hydroperoxide Reductase C from Pseudomonas aeruginosa PAO1 Resulting from a Point-Specific Mutation Confers Heat Tolerance in Escherichia coli

  • Lee, Jae Taek;Lee, Seung Sik;Mondal, Suvendu;Tripathi, Bhumi Nath;Kim, Siu;Lee, Keun Woo;Hong, Sung Hyun;Bai, Hyoung-Woo;Cho, Jae-Young;Chung, Byung Yeoup
    • Molecules and Cells
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    • 제39권8호
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    • pp.594-602
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    • 2016
  • Alkyl hydroperoxide reductase subunit C from Pseudomonas aeruginosa PAO1 (PaAhpC) is a member of the 2-Cys peroxiredoxin family. Here, we examined the peroxidase and molecular chaperone functions of PaAhpC using a site-directed mutagenesis approach by substitution of Ser and Thr residues with Cys at positions 78 and 105 located between two catalytic cysteines. Substitution of Ser with Cys at position 78 enhanced the chaperone activity of the mutant (S78C-PaAhpC) by approximately 9-fold compared with that of the wild-type protein (WT-PaAhpC). This increased activity may have been associated with the proportionate increase in the high-molecular-weight (HMW) fraction and enhanced hydrophobicity of S78C-PaAhpC. Homology modeling revealed that mutation of $Ser^{78}$ to $Cys^{78}$ resulted in a more compact decameric structure than that observed in WT-PaAhpC and decreased the atomic distance between the two neighboring sulfur atoms of $Cys^{78}$ in the dimer-dimer interface of S78C-PaAhpC, which could be responsible for the enhanced hydrophobic interaction at the dimer-dimer interface. Furthermore, complementation assays showed that S78C-PaAhpC exhibited greatly improved the heat tolerance, resulting in enhanced1 survival under thermal stress. Thus, addition of Cys at position 78 in PaAhpC modulated the functional shifting of this protein from a peroxidase to a chaperone.

두경부(Head & Neck)종양에서 Forward IMRT 유용성에 관한 고찰 (The usefulness of Forward IMRT for Head and Neck Cancer)

  • 백금문;김대섭;박광호;김정만
    • 대한방사선치료학회지
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    • 제15권1호
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    • pp.41-52
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    • 2003
  • I. 목적 방사선 치료계획에 있어서 정상조직의 선량과 치료부위 선량의 분포는 매우 중요하다. 또한 치료부위의 균일한 선량분포를 얻기 위하여 여러 가지 방법을 이용하고 있다. 특히 두경부(Head & Neck) 종양의 방사선 치료 시 체표 윤곽의 변화가 심하여 이에 따른 선량 불균일 보정이 필요하다. 기존의 치료방법으로는 parotid gland 와 spinal cord 의 tolerance dose 이하를 유지하면서 planning target volume(PTV)에 충분한 치료 선량을 전달하기에는 여러 가지 어려움이 있다. 이에 본원에서는 Forward IMRT를 이용한 방사선 치료의 유용성 및 실용적인 정도관리 방법에 관한 연구를 하였다. II. 대상 및 방법 본 연구는 두경부(Head & Neck) 종양 비인두암(nasophrygeal cancer)의 방사선 치료가 요구되는 환자를 대상으로 하여 2차원적인 치료계획과 dynamic Mulit-Leaf Collimator(dMLC)를 이용하여 partial block technique(PBT)방법을 적용한 Forward IMRT를 위한 치료계획을 dose volume histogram(DVH)로 비교 분석하였다. 또한 정도관리(quality assurance, QA)를 위하여 필름과 pinpoint chamber를 이용하여 정확한 선량 평가를 실시하였다. III. 결과 2차원적인 치료계획과 Forward IMRT를 적용한 치료계획의 DVH를 비교 분석한 결과 Forward IMRT를 적용한 치료계획이 Rt, Lt parotid gland와 spinal cord에 들어가는 선량을 좀더 줄일 수 있었다. 이러한 Forward IMRT의 시도로 조사면의 방사선 세기가 정상조직의 보호를 개선시키고 치료의 최적화를 이룰 수 있었다. Inverse IMRT에 비해 기존의 3차원적 치료계획 장치를 이용할 수 있고 비교적 단순한 방사선 세기 패턴이므로 정도관리가 용이하였다. IV. 결론 Forward IMRT는 2차원적인 치료법에 비하여 PTV에는 균일한 선량분포를 이루면서 정상조직에는 tolerance dose 이하로 선량을 전달 할 수 있는 치료기법이었다.

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재생과 증식에 기인하는 선량률 효과 (Dose-Rate Effects Generated from Repair and Regeneration)

  • 이본녕;조관호;막스 리차드;김재호
    • Radiation Oncology Journal
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    • 제7권2호
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    • pp.171-183
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    • 1989
  • Roesch의 생존 방정식속에 세포증식으로 일어나는 생존증가를 가장 일반적 형식으로 포함시킨 식을 유도하고 이 식으로부터 저선량률 방사선에만 적용되는 동결과선량식 (Isoeffect formula)을 유도하였다. 이 저선량률식이 파라메터 하나로 결정해주는 총선량은 Paterson과 Green에 의하여 얻어진 실험 임상결과와 일치한다. 이 파라메터와 선량률 효과 사이의 관계의 의의를 논하였다. 또한 고선량률 분절(fractionation) 치료와 동저선량률 계속치료를 연락하는 동결과 선량식을 유도 사용하여, Ellis가 잰 실험결과와 비교하였다. 그 결과, Ellis와 Paterson이 쓴 'tolerance'의 표준이 $\alpha/\beta$의 비 4Gy에 해당하는 것임이 밝혀졌다. 그러므로 이들의 'tolerance'의 표준은 'early effect'에만 두고 본 것이 아님을 알 수 있다. 개념적인 면에서도, 아래와 같은 새로운 견해가 나올 수 있다. KHT sarcoma의 생존선도 (survival curve)에 선량률 효과가 보이지 않는 이유로 $\alpha/\beta$의 비가 큰 점을 들을 수 있다. 이것은 이 survival curve에 어께 (shoulder)가 보이지 않는 것으로도 증명이 된다. Pierquin이 선량률에 무관하게 head and neck tumor치료에 같은 총선량을 쓴 것을 정당화시킬 수 있다.

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전산화단층 모의치료장치의 정도관리 항목 제안 (Proposal of CT Simulator Quality Assurance Items)

  • 김연래;윤영우;정재용;이정우;정진범
    • 대한방사선기술학회지:방사선기술과학
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    • 제44권4호
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    • pp.367-373
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    • 2021
  • A quality assurance of computed tomography(CT) have done seven items that were water attenuation coefficient, noise, homogeneity, spatial resolution, contrast resolution, slice thickness, artifact using by standard phantom. But there is no quality assurance items and methods for CT simulator at domestic institutions yet. Therefore the study aimed to access the CT dose index(CTDI), table tilting, image distortion, laser accuracy, table movement accuracy and CT seven items for CT simulator quality assurance. The CTDI at the center of the head phantom was 0.81 for 80 kVp, 1.55 for 100 kVp, 2.50 for 120 mm, 0.22 for 80 kVp at the center of the body phantom, 0.469 for 100 kVp, and 0.81 for 120 kVp. The table tilting was within the tolerance range of ±1.0° or less. Image distortion had 1 mm distortion in the left and right images based on the center, and the laser accuracy was measured within ±2 mm tolerance. The purpose of this study is to improve the quality assurance items suitable for the current situation in Korea in order to protect the normal tissues during the radiation treatment process and manage the CT simulator that is implemented to find the location of the tumor more clearly. In order to improve the accuracy of the CT simulator when looking at the results, the error range of each item should be small. It is hoped that the quality assurance items of the CT simulator will be improved by suggesting the quality assurance direction of the CT simulator in this study, and the results of radiation therapy will also improve.

Induction of Oral Tolerance by Gamma-Irradiated Ovalbumin Administration

  • Yang, Hui;Lee, Junglim;Seo, Ji Hyun;Oh, Kwang Hoon;Cho, Young Ho;Yoo, Yung Choon
    • 한국축산식품학회지
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    • 제36권1호
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    • pp.14-18
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    • 2016
  • Oral administration of soluble antigen can induce peripheral tolerance to the antigen. This study was conducted to evaluate whether gamma-irradiated ovalbumin (OVA) can induce oral tolerance. To investigate this, we administrated intact or irradiated OVA to mice, induced allergic response using intact OVA and alum, then compared humoral and cellular immune responses. Mice treated with gammairradiated OVA had less OVA-specific IgE compared with those who were administered intact OVA. There was no difference in levels of OVA-specific IgG+A+M, IgG1, and IgG2a. Splenocytes of mice administered irradiated OVA showed similar OVA-specific T cell proliferation and secretion of IFN-γ and IL-4. However, there was an increase in IL-2 and a decrease of IL-6 secretion in mice treated with irradiated OVA. These results indicate that gamma-irradiated OVA have similar effects to intact OVA on antigen tolerance.