• Title/Summary/Keyword: radiation tolerance

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The Evaluation of Hybrid-Volumetric Modulated Arc Therapy for Lung Cancer Radiation Therapy (폐암 방사선 치료 시 Hybrid-Volumetric Modulated Arc Therapy의 유용성 평가)

  • Lee, Geon Ho;Kang, Hyo Seok;Choi, Byoung Joon;Park, Sang Jun;Jung, Da Ee;Lee, Du Sang;Ahn, Min Woo;Jeon, Myeong Soo
    • The Journal of Korean Society for Radiation Therapy
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    • v.29 no.2
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    • pp.19-26
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    • 2017
  • Objectives: In the Lung, the VMAT rotates continuously and examines radiation. That increases the low doses to normal lung. Due to that, the incidence of radiation pneumonia among radiation side effects may increase. The cause of radiation pneumonia is the lower dose area of the lungs. The H-VMAT was applied to patients who applied to reduce radiation in the lower doses of the lungs. We wanted to assess the usefulness of the H-VMAT by comparing the radiation doses to the low dose areas of the lungs and the normal organs. Materials and Methods: A total of 26 patients who applied for a H-VMAT procedure were applied to the patient. The prescription dose applied to total dose 44 Gy from 22 divisions. For each patient, a plan was implemented with Conventional RT, VMAT and H-VMAT. Conventional RT was carried out in four to five fields each, considering the size, location, shape, and location of the PTV. In the case of a VMAT plan, the two Half ARC, three Half ARC method and the two Full ARC were planned. The H-VMAT was planned by adding two Static fields in the VMAT, taking into account the dose of the lung and the tolerance dose of the organs. Results: In the NSCLC, the lung doses $V_5$ and $V_{10}$ of the lungs except for the treatment plan volume were the lowest with $55.40{\pm}13.39%$ and $32.05{\pm}11.37%$ of H-VMAT. And, in the SCLC, the lung doses of V5 and V10 were the lowest at $64.32{\pm}16.15%$ and $35.50{\pm}9.91%$, respectively. The spinal dose of VMAT in NSCLC was $21.15{\pm}4.02Gy$, which was 7.94 Gy lower than other treatment methods. The lowest spinal dose was delivered at $19.72{\pm}1.82Gy$ for SCLC. The mean dose delivered to the esophagus was also $17.44{\pm}2.04Gy$ and $17.84{\pm}9.20Gy$ in SCLC and NSCLC, respectively. Conclusion: When comparing the value of the surrounding normal organ dose, the VMAT showed that less doses were transmitted from the heart, esophagus and spinal cord than the rest of the treatment plan. However, it was similar to VMAT in normal organs except for the spinal cord. VMAT has increased doses of some normal organs but did not exceed the tolerance dose. It showed a low value in $V_5$, $V_{10}$. When comparing Conventional RT, VMAT, and H-VMAT, If the dose to the heart, esophagus and spinal cord is lower than the tolerance dose, it is thought to reduce the incidence of radiation pneumonia by applying H-VMAT that show the benefits of low doses of the lungs.

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A Study on lung dose of Intensity modulated and volumetric modulated arc therapy plans using restricted angle of Non-small cell lung cancer (비소세포 폐암의 제한된 각도를 이용한 세기변조와 용적변조회전 방사선치료계획의 폐 선량에 관한 연구)

  • Yeom, Misuk;Lee, Woosuk;Kim, Daesup;Back, Geummun
    • The Journal of Korean Society for Radiation Therapy
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    • v.26 no.1
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    • pp.21-28
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    • 2014
  • Purpose : For non-small cell lung cancer, if the treatment volume is large or the total lung volume is small, and the tumor is located in midline of patient's body, total lung dose tends to increase due to tolerance dose of spinal cord. The purpose of this study is to compare and evaluate the total lung dose of three dimensional conformal radiotherapy(3D CRT), intensity modulated radiotherapy(IMRT) and volumetric modulated arc therapy(VMAT) using restricted angle for non-small cell lung cancer patients. Materials and Methods : The treatment plans for four patients, being treated on TrueBeam STx($Varian^{TM}$, USA) with 10 MV and prescribed dose of 60 Gy in 30 fractions, 3D CRT, restricted angle IMRT and VAMT radiotherapy plans were established. Planning target volume(PTV), dose to total lung and spinal cord were evaluated using the dose volume histogram(DVH). Conformity index(CI), homogeneity index(HI), Paddick's index(PCI) for the PTV, $V_{30}$, $V_{20}$, $V_{10}$, $V_5$, mean dose for total lung and maximum dose for spinal cord was assessed. Results : Average value of CI, HI and PCI for PTV was $0.944{\pm}0.009$, $1.106{\pm}0.027$, $1.084{\pm}0.016$ respectively. $V_{20}$ values from 3D CRT, IMRT and VMAT plans were 30.7%, 20.2% and 21.2% for the first patient, 33.0%, 29.2% and 31.5% for second patient, 51.3%, 34.3% and 36.9% for third patient, finally 56.9%, 33.7% and 40.0% for the last patient. It was noticed that the $V_{20}$ was lowest in the IMRT plan using restricted angle. Maximum dose for spinal cord was evaluated to lower than the tolerance dose. Conclusion : For non-small cell lung cancer, IMRT with restricted angle or VMAT could minimize the lung dose and lower the dose to spinal cord below the tolerance level. Considering PTV coverage and tolerance dose to spinal cord, it was possible to obtain IMRT plan with smaller angle and this could result in lower dose to lung when compared to VMAT.

Expression of Antioxidant Isoenzyme Genes in Rice under Salt Stress and Effects of Jasmonic Acid and ${\gamma}$-Radiation

  • Kim, Jin-Hong;Chung, Byung-Yeoup;Baek, Myung-Hwa;Wi, Seung-Gon;Yang, Dae-Hwa;Lee, Myung-Chul;Kim, Jae-Sung
    • Journal of Applied Biological Chemistry
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    • v.48 no.1
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    • pp.1-6
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    • 2005
  • Analysis of chlorophyll (Chl) fluorescence implicated treatment of 40 mM NaCl decreased maximal photochemical efficiency of photosystem II (PSII) (Fv/Fm), actual quantum yield of PSII (${\Phi}_{PSII}$), and photochemical quenching (qP) in rice, but increased non-photochemical quenching (NPQ). Decreases in Fv/Fm, ${\Phi}_{PSII}$, and qP were significantly alleviated by $30\;{\mu}M$ jasmonic acid (JA), while NPQ increase was enhanced. Transcription levels of antioxidant isoenzyme genes were differentially modulated by NaCl treatment. Expression of cCuZn-SOD2 gene increased, while those of cAPXb, CATb, and CATc genes decreased. JA prevented salt-induced decrease of pCuZn-SOD gene expression, but caused greater decrease in mRNA levels of cAPXa and Chl_tAPX genes. Investigation of vacuolar $Na^+/H^+$ exchanger (NHX2) and 1-pyrroline-5-carboxylate synthetase (P5CS) gene expressions revealed transcription level of NHX2 gene was increased by JA, regardless of NaCl presence, while that of P5CS gene slightly increased only in co-presence of JA and NaCl. Unlike JA, ${\gamma}$-radiation rarely affected expressions of antioxidant isoenzyme, NHX2, and P5CS genes, except for increase in mRNA level of Chl_tAPX and decrease in that of pCuZn-SOD. These results demonstrate enhanced salt-tolerance in JA-treated rice seedlings may be partly due to high transcription levels of pCuZn-SOD, NHX2, and P5CS genes under salt stress.

Protein Profiles in Response to Salt Stress in Seedling of Salt Tolerant Rice Mutants

  • Song, Jae Young;Kim, Dong Sub;Lee, Myung-Chul;Lee, Kyung Jun;Kim, Jin-Baek;Kim, Sang Hoon;Ha, Bo-Keun;Lee, Young-Keun;Kang, Si-Yong
    • Journal of Radiation Industry
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    • v.6 no.2
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    • pp.129-138
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    • 2012
  • Proteomic analysis was performed in order to identify proteomic changes by salt stress between the Japonica cv. Donganbyeo (WT) and two salt-tolerant (ST) mutant lines by using the SDS-PAGE and 2-DE. Two salt tolerant rice mutant lines, ST-87 and ST-301, were selected by in vitro mutagenesis with gamma-ray. Three-week-old seedlings were treated with 171 mM NaCl for 7 days. In the SDS-PAGE, three proteins with molecular weights of 27, 46 and 58 kDa were highly increased under salt treatment. Total proteins from shoots of both WT and ST-lines were separated by two-dimensional gel electrophoresis. In 2-DE, 201, 226, 217 and 213 protein spots were detected in the untreated-or treated-WT and untreated- or treated-ST-87, respectively. Of theses, 17 and 10 protein spots were up- and down-regulated under salt stress in the WT, respectively. While, 16 and 8 protein spots were up- and down-regulated under salt stress in the ST-87, respectively, compared with the untreated plants. High intensity or de novo synthesized proteins were analyzed by MALDI-TOF/MS analysis.

Manufacture of Immobilization Device (Vac-lok) and the Usefulness of Evaluation for Reproducibility of Patients in the Radiotherapy (환자의 재현성을 위한 고정장치(Vac-lok) 제작과 방사선치료에서 유용성 평가)

  • Lee, Jae-Seung;Kim, Gyoung-Hee;Jeong, Kyu-Hwan;Kweon, Dae-Cheol;Goo, Eun-Hoe;Park, Cheol-Woo;Im, In-Chul;Dong, Kyung-Rae;Chung, Woon-Kwan
    • Journal of Radiation Protection and Research
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    • v.36 no.1
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    • pp.8-16
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    • 2011
  • We manufactured the Vac-lok that can be applied to patient of special body shape and need to special set-up position and evaluated the usefulness in the radiation therapy. The manufacture Vac-lok, It was used EVA resin and biobeadform of a diameter 1.5 mm. carried out the test of functionality, structural and analyzed the relative reproducibility of phantoms and patients. During the total period of radiation therapy, Vacuum pressure bring variety to a very small amount in the test of functionality of the manufacture Vac-lok. But It was a negligible quantity. The manufacture Vac-lok improved the relative reproducibility of phantoms than the existing Vac-lok and tolerance has a confidence less than 4% error. Also, relative reproducibility of patient increased error than phantom in the antero-posterior and lateral plan. However, the maximum set-up error was less than ${\pm}\;2.3$ mm. In conclusion, If tolerance set-up error of radiotherapy is less than ${\pm}\;3$ mm, the manufacture Vac-lok was enough possible to use and improvement of reproducibility, considering supply with the Vac-lok made to measure of special patient that produced at a low price and without delay.

irrE, an Exogenous Gene from Deinococcus radiodurans, Improves the Growth of and Ethanol Production by a Zymomonas mobilis Strain Under Ethanol and Acid Stresses

  • Zhang, Ying;Ma, Ruiqiang;Zhao, Zhonglin;Zhou, Zhengfu;Lu, Wei;Zhang, Wei;Chen, Ming
    • Journal of Microbiology and Biotechnology
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    • v.20 no.7
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    • pp.1156-1162
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    • 2010
  • During ethanol fermentation, bacterial strains may encounter various stresses, such as ethanol and acid shock, which adversely affect cell viability and the production of ethanol. Therefore, ethanologenic strains that tolerate abiotic stresses are highly desirable. Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation, ultraviolet light, and desiccation, and therefore constitute an important pool of extreme resistance genes. The irrE gene encodes a general switch responsible for the extreme radioresistance of D. radiodurans. Here, we present evidence that IrrE, acting as a global regulator, confers high stress tolerance to a Zymomonas mobilis strain. Expression of the gene protected Z. mobilis cells against ethanol, acid, osmotic, and thermal shocks. It also markedly improved cell viability, the expression levels and enzyme activities of pyruvate decarboxylase and alcohol dehydrogenase, and the production of ethanol under both ethanol and acid stresses. These data suggest that irrE is a potentially promising gene for improving the abiotic stress tolerance of ethanologenic bacterial strains.

Dose Effect of Phytosanitary Irradiation on the Postharvest Quality of Cut Flowers

  • Kwon, Song;Kwon, Hye Jin;Ryu, Ju Hyun;Kim, Yu Ri
    • Journal of People, Plants, and Environment
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    • v.23 no.2
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    • pp.171-178
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    • 2020
  • The present study was conducted to determine the effects of electron beam irradiation on the postharvest quality of cut flowers. Cut flowers were irradiated with electron beam at 100, 200, 400, 600, 800, 1,000, and 2,000 Gy with a 10 MeV linear electron beam accelerator to evaluate their irradiation tolerance. Postharvest quality was determined by monitoring fresh weight loss, flower longevity, flower diameter, flowering rate, visual quality of flowers and leaves, and chlorophyll content. Cut flowers showed a radiation-induced damage with increasing the irradiation dose. Flower longevity and fresh weight of cut flowers decreased when the irradiation dose was increased. Flower bud opening was also inhibited in a dose-dependent manner. The effective irradiation doses for 10% reduction of postharvest quality (ED10) values were 144.4, 451.6, and 841.2 Gy in the 'Medusa' lily, 'Montezuma' carnation, and 'Rosina White' eustoma, respectively. Although tolerance of cut flowers to electron beam irradiation vary according to species, cultivars, or maturity stage conditions, it is conceivable that 'Montezuma' carnation and 'Rosina White' eustoma could be tolerated and maintained overall postharvest quality up to 400 Gy, the generic irradiation dose approved by the Animal and Plant Health Inspection Service (APHIS) and the International Plant Protection Convention (IPPC) for postharvest phytosanitary treatments.

Reliability Analysis of Interleaved Memory with a Scrubbing Technique (인터리빙 구조를 갖는 메모리의 스크러빙 기법 적용에 따른 신뢰도 해석)

  • Ryu, Sang-Moon
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.4
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    • pp.443-448
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    • 2014
  • Soft errors in memory devices that caused by radiation are the main threat from a reliability point of view. This threat can be commonly overcome with the combination of SEC (Single-Error Correction) codes and scrubbing technique. The interleaving architecture can give memory devices the ability of tolerating these soft errors, especially against multiple-bit soft errors. And the interleaving distance plays a key role in building the tolerance against multiple-bit soft errors. This paper proposes a reliability model of an interleaved memory device which suffers from multiple-bit soft errors and are protected by a combination of SEC code and scrubbing. The proposed model shows how the interleaving distance works to improve the reliability and can be used to make a decision in determining optimal scrubbing technique to meet the demands in reliability.

A Comparison of Patient-specific Delivery Quality Assurance (DQA) Devices in Radiation Therapy (방사선치료에서 환자맞춤형 선량품질보증 장치의 비교)

  • Kyung Hwan Chang
    • Journal of radiological science and technology
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    • v.46 no.3
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    • pp.231-238
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    • 2023
  • This study aimed to compare the results of delivery quality assurance (DQA) using MapCHECK and OCTAVIUS for radiation therapy. Thirty patients who passed the DQA results were retrospectively included in this study. The point dose difference (DD) and gamma passing rate (GPR) were analyzed to evaluate the agreement between the measured and planned data for all cases, Plan complexity was evaluated to analyze dosimetric accuracy by quantifying the degree of modulation according to each plan. We analyzed the monitor units (MUs) and total MUs for each plan to evaluate the correlation between the MUs and plan complexity. We used a paired t-test to compare the DD and GPRs that were obtained using the two devices. The DDs and GPRs were within the tolerance range for all cases. The average GPRs difference between the two devices was statistically significant for the brain, and head and neck for gamma criteria of 3%/3 mm and 2%/2 mm. There was no significant correlation between the modulation index and total MUs for any of the cases. These DQA devices can be used interchangeably for routine patient-specific QA in radiation therapy.

The Effect of Total Radiation Dose on Normal Spinal Cord of Hybrid Mice -Early Pathological Changes- (총 방사선 조사량이 잡종 백색 마우스의 정상 척수에 미치는 영향)

  • Shon, Sung-Won;Kim, Myung-Se;Choi, Won-Hee
    • Radiation Oncology Journal
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    • v.4 no.2
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    • pp.107-113
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    • 1986
  • Radiation myelitis is a rather rare, but irreversible fatal complication. Etiology, pathologic change, clinical symptoms and the method of diagnosis have been studied with animal experiments and human necropsies. In spite of massive studies, pathogenesis of post-irradiation myelitis and the level of tolerance dose still remain controversial. Thoracolumbar spine of 110 hybrid mice were irradiated with orthovoltage x-ray machine. Mild capillary congestion and axonal swelling were observed in 1,000 rad irradiated specimens. Focal necrosis in 3,500 rad specimens, fragmentation of neural tissue in 4,000 rad specimens were also observed. These results suggest that 5,000 rad is not a completely safe tolerable dose which have been accepted and we cannot exclude direct radiation damage to news tissue as the causative pathology of radiation myelitis in addition to blood vessel damage.

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