• Title/Summary/Keyword: MV weight

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Dosimetric comparison for Prostate VMAT of weight and photon energy change (전립선 암 입체적세기변조방사선치료 시 체형 및 에너지 변화에 따른 선량 평가)

  • Jo, Guang Sub;Kim, Min Woo;Baek, Min Gyu;Chae, Jong Pyo;Ha, Se Min;Lee, Sang Bong
    • The Journal of Korean Society for Radiation Therapy
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    • v.30 no.1_2
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    • pp.17-25
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    • 2018
  • Purpose : To compare the radiation doses of prostate cancer patients according to changes in abdominal body shape and energy during Volumetric modulated arc therapy(VMAT). Materials and Methods : Seven patients with prostate cancer were enrolled in this study. VMAT treatment plan was established at 6, 10, and 15 MV while changing from -2.0 cm to 2 cm by 0.5 cm. Conformal index(CI), homogeneous index(HI), $D_{max}$, $D_{95%}$, $D_{50%}$ and $D_{2%}$ of PTV were examined in order to evaluate the change of dose in the target organ according to body shape change. Normal organ of the femoral head, rectum and bladder was analyzed to evaluate dose changes. Results : The dose of $D_{max}$ 6 MV in PTV increased to 107.2 % in 1.0 cm body shape reduction, and 10 MV and 15 MV dose increased to 107.1 % and 107.0 % in 1.5 cm body reduction, respectively. The dose of $D_{50%}$ 6 MV in PTV decreased to 99.64 % in 1.0 cm body shape increase, and in 10 MV and 15 MV dose decreased to 99.79 % and 99.97 % in 1.5 cm body increase, respectively. In 2.0 cm body type increase, the dose was decreased to 99.30 % and 99.52 %, respectively. Doses for rectum and bladder gradually increased with decreasing weight, and dose decreased with decreasing weight. 6 MV, and $V_{70Gy}$ at 10 MV increased from 11.50 % to 12.76 % when the external shape decreased by 2.0 cm. The bladder $V_{70Gy}$ also increased from 14.0 % to 15.2 %. It was also shown that the dose increased as the body weight decreased in the femoral head. Conclusion : In the treatment of VMAT, dose distribution can be changed according to the change of abdominal shape. SSD and CBCT were used to decrease the body shape by more than 1cm or more than 1.0 cm at 6 MV and the body shape by more than 1.5 cm or more than 1.5 cm at 10 MV or 15 MV. It is considered that a new treatment plan should be established through re-simulation.

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대향2문조사시 Target Volume의 위치에 따른 Beam Weight의 최적화

  • Lee Jin Guk;Kim Ji Han;Im Ik Su;Choe Yeong Heon
    • The Journal of Korean Society for Radiation Therapy
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    • v.5 no.1
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    • pp.68-73
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    • 1992
  • If the same weight is used in parallel opposed 6 and 10 MV x-ray beams, the lowest dose is achieved at SAD. Therefore, dose homogeneity in the target volume is decreased when SAD is taken at center of target volume than center of phantom or patient. With Standard deviation of ${\pm}6\%$ that repuesented the dose homogeneity in tarhet volume, we studied the optimized beam weights at which hot spot dose was least in parallel opposed beams. The optimized beam weights that maximally decrease the hot spot dose, wer 1.29, 1.19, 2.71, 3.50, and 4.70 in 6 MV x-ray and 1.25, 1.53, 1.90, 2.36, 3.01, and 3.7 in 10 MV x-ray, reapectively, when center of target volume was changed to 2,4,6,8,10, and 12cm from center plan of phantom along the centeral axis of beams.

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Breast Radiotherapy with Mixed Energy Photons; a Model for Optimal Beam Weighting

  • Birgani, Mohammadjavad Tahmasebi;Fatahiasl, Jafar;Hosseini, Seyed Mohammad;Bagheri, Ali;Behrooz, Mohammad Ali;Zabiehzadeh, Mansour;meskani, Reza;Gomari, Maryam Talaei
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7785-7788
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    • 2015
  • Utilization of high energy photons (>10MV) with an optimal weight using a mixed energy technique is a practical way to generate a homogenous dose distribution while maintaining adequate target coverage in intact breast radiotherapy. This study represents a model for estimation of this optimal weight for day to day clinical usage. For this purpose, treatment planning computed tomography scans of thirty-three consecutive early stage breast cancer patients following breast conservation surgery were analyzed. After delineation of the breast clinical target volume (CTV) and placing opposed wedge paired isocenteric tangential portals, dosimeteric calculations were conducted and dose volume histograms (DVHs) were generated, first with pure 6MV photons and then these calculations were repeated ten times with incorporating 18MV photons (ten percent increase in weight per step) in each individual patient. For each calculation two indexes including maximum dose in the breast CTV ($D_{max}$) and the volume of CTV which covered with 95% Isodose line ($V_{CTV,95%IDL}$) were measured according to the DVH data and then normalized values were plotted in a graph. The optimal weight of 18MV photons was defined as the intersection point of $D_{max}$ and $V_{CTV,95%IDL}$ graphs. For creating a model to predict this optimal weight multiple linear regression analysis was used based on some of the breast and tangential field parameters. The best fitting model for prediction of 18MV photons optimal weight in breast radiotherapy using mixed energy technique, incorporated chest wall separation plus central lung distance (Adjusted R2=0.776). In conclusion, this study represents a model for the estimation of optimal beam weighting in breast radiotherapy using mixed photon energy technique for routine day to day clinical usage.

Symptomatology of Citrus mosaic sadwavirus (CiMV) in Some Citrus Cultivars and Effect of CiMV Infection on Citrus Fruit Quality

  • Hyun, Jae Wook;Hwang, Rok Yeon;Choi, Cheol Woo;Jung, Kyung Eun;Han, Seung Gab
    • The Plant Pathology Journal
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    • v.36 no.1
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    • pp.106-110
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    • 2020
  • Citrus mosaic sadwavirus (CiMV) is a closely related virus with the Satsuma dwarf virus (SDV) along with Navel orange infectious mottling virus (NIMV), Natsudaidai dwarf virus (NDV), and Hyugagatsu virus (HV). The present study found that the typical symptoms of CiMV-infected citrus fruits include the appearance of dark blue speckles or ringspots on fruit rinds and the browning of oil glands in the spots as rind coloring began. As rind coloring progressed, the spots gradually faded, whereas the browning of the oil glands worsened to the point that the tissues surrounding the oil glands became necrotic. In very early satsuma mandarins (Citrus unshiu 'Miyamoto Wase') and 'Setoka' cultivar (C. hybrid 'Setoka') of late-maturity citrus, the symptomatic fruits were eventually dropped. And in early satsuma mandarin (C. unshiu 'Miyakawa Wase'), the peel hardness of the virus-infected fruit (1,618.3 ± 305.5, g-force) was more than twice as hard as that of the healthy fruit (636.5 ± 39.1, g-force). The ratio of flesh weight to total fruit weight was higher for the healthy fruit (77.3 ± 1.7%) than for the infected fruit (70.7 ± 0.6) and peel puffing was more severe in the infected fruit (2.9 ± 0.4 mm) than in the healthy fruit (0.9 ± 0.2 mm). The soluble solids content in infected citrus fruits was less values than the healthy fruit by 0.5-1.5 °Brix. These findings reveal that CiMV infection on citrus trees reduces the fruit quality of citrus.

Association between Hair Mineral Content and Nutritional Status in Vegetarians and Non-Vegetarians (채식과 비채식인의 모발 내 무기질 함량과 영양상태의 관련성)

  • Cho, Jung-Hee;Kim, Mi-Kyoung;Kim, So-Hyeon;Cho, Sang-Woon;Park, Yoo-Kyoung
    • Journal of Nutrition and Health
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    • v.44 no.3
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    • pp.203-211
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    • 2011
  • Previous studies have shown that plant-based vegetarian diets, which typically contain a variety of antioxidants and dietary fiber, help reduce the risk of heart disease, diabetes, obesity, and cancer. However, some studies have reported that vegetarian diets can lead to deficiencies in protein and trace minerals compared to non-vegetarian diets. This study was conducted to compare anthropometric measurements, blood parameters, dietary intake, and hair mineral status in long-term vegetarians (MV; moderate vegan, LV; lacto-ovo vegetarian) and non-vegetarians (NV). Thirty MV (12 males, 18 females; mean age, $50.58{\pm}5.05$ years), 15 LV (11 males, four females; mean age, $49.45{\pm}4.97$ years), and 30 NV (15 males, 15 females; mean age, $48.90{\pm}3.62$ years) participated. No significant differences were observed for age, height, weight, or body mass index, but body fat was significant lower in MV and LV males than that in NV males. White blood cell counts of MV, LV, and NV male subjects were significantly different. Dietary intake data showed that plant protein and plant iron intake were significantly higher in MV and LV than those in NV. Animal protein, animal fat, and animal iron intake were significantly higher in NV than those in MV and LV. A hair mineral analysis showed that calcium and iron were higher in the hair of MV and LV than those in NV. Zinc concentration in hair was not significantly different among the groups. The results suggest that vegetarian diets are adequate to sustain mineral status to at least the same degree as that of non-vegetarian diets.

Detection of Plant RNA Viruses by Hybridization Using In Vitro Transcribed RNA Probes (In Viro 전사 RNA Probe를 이용한 식물 바이러스병의 진단)

  • 최장경;이종희;함영일
    • Korean Journal Plant Pathology
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    • v.11 no.4
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    • pp.367-373
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    • 1995
  • The cDNAs derived from the coat protein (CP) genes of six plant RNA viruses, tobacco mosaic virus-pepper strains (TMV-P) and -ordinary strain (TMV-OM), potato virus Y (PVY), turnip mosaic virus (TuMV), cucumber mosaic virus (CMV) and potato leafroll virus (PLRV), were subcloned into the transcription vector, pSPT18, containing SP6 and T7 promoters. The digoxigenin (DIG)-labeled RNA polymerase after linearlization of the cloned pSPTs with XbaI or SacI, and were tested for their sensitivities for the detection of the six viruses. In slot-blot hybridization, dilution end points for the detection of TMV-P and TMV-OM were 10-4, while those of PVY, TuMV and CMV were 10-3. PLRV was detected at the dilution of 10-2. When each RNA probe was applied for the detection of the viruses in the preparations from the leaf disks (8 mm in diameter, and 12 to 15 mg in weight) of infected natural host plants, TMV-P, TMV-OM and TuMV could be detected from one disk, while PVY from 1 or 2 disks. CMV was detected in the preparation from two disks, and PLRV from three disks. With DIG-labeled RNA probe, PVY was detected at 5 days after inoculation, but with ELISA the virus was detected at 8 days after inoculation to tobacco (Nicotiana tabacum cv. Xanthi nc) plants on which symptoms appeared at 9 days after inoculation. No difference was observed in cross reaction between the RNA probes for the detection of TMV-P and TMV-OM.

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Identification of a New Potyvirus Associated with Chlorotic Vein Banding Disease of Spathiphyllum spp., in Andhra Pradesh, India

  • Padmavathi, M.;Srinivas, K.P.;Reddy, Ch. V. Subba;Ramesh, B.;Navodayam, K.;Krishnaprasadji, J.;Babu, P. Ratan;Sreenivasulu, P.
    • The Plant Pathology Journal
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    • v.27 no.1
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    • pp.33-36
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    • 2011
  • The genome of a potyvirus isolate associated with chlorotic spots and vein banding symptoms on Spathiphyllum spp., in Andhra Pradesh state, India was amplified by RT-PCR using degenerate potyvirus primers, amplicons cloned, and sequence (1.6 kb) analyzed. This virus isolate shared maximum identity of 74.8% and 80.2% at coat protein (CP) gene nucleotide (906 nucleotides) and amino acid (302 amino acids) levels, respectively with Dasheen mosaic virus (DsMV)-M13 isolate reported from China. But its 3'-UTR (258 nucleotides) had maximum identity of 62.5% with DsMV-Vietnam isolate. The deduced molecular weight of CP is 33.57 kDa and it contained DAG triplet in its N-terminal region. In CP amino acid based phylogenetic analysis, this virus isolate represented a separate branch but closer to DsMV isolates cluster. Based on the molecular criteria set for the discrimination of species and genus in the Potyviridae family, the present virus isolate was identified as a distinct virus species in the genus Potyvirus and proposed the name Spathiphyllum chlorotic vein banding virus (SCVbV).

Expression of resveratrol synthase gene and accumulation of resveratrol in transgenic potatoes (Solanum tuberosum L.)

  • Yi, Jung Yoon;Seo, Hyo Won;Yun, Song Joong;Ok, HyunChoong;Park, YoungEun;Cho, Ji Hong;Cho, HyunMook
    • Korean Journal of Breeding Science
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    • v.41 no.4
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    • pp.385-390
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    • 2009
  • A resveratrol synthase (RS) gene was isolated from peanut (Arachis hypogaea, L. cv. Jinpoong) plants. This gene was placed under the control of the cauliflower mosaic virus 35S promoter (CaMV35S) and introduced into two Korean varieties of potato (Solanum tuberosum L. cvs. Jasim and Jowon) plants by Agrobacterium-mediated gene transfer. Putative transformants were screened by PCR with primers designed from CaMV 35S promoter, NOS terminator and RS gene. Most of selected transgenic potato plants showed the amplification of expected fragments by PCR of genomic DNA with gene-specific primers, while they were absent in untransformed control plants. Expression of the resveratrol synthase gene was also examined by northern blot analysis. The transformants showed a band which was lacking in the control plant, confirming that the introduced gene is transcribed into mRNA in the transformants. The strength of the band, which reflected the level of mRNA expression, differed among the individual transformants. Among the transformants obtained, the highest trans-resveratrol content in the transgenic young leaves of purple-fleshed "Jashim" was $2.11{\mu}gg^{-1}$ fresh weight and that in the microtubers in vitro of purple fleshed "Jashim" was $8.31{\mu}gg^{-1}$ fresh weight. This amount of resveratrol may have a positive biological effect on human health.

Gene Manipulation of Pin 2(Proteinase Inhibitor II) to the Cottonwood Leaf Beetle(Coleoptera : Chrysomelidae) in Transgenic Poplar(Populus deltodies × P. nigra) (형질전환(形質轉換)된 포플러의 딱정벌레에 대한 저항성(抵抗性) 유전자(遺傳子)(Proteinase Inhibitor II) 발현(發現))

  • Kang, Hoduck
    • Journal of Korean Society of Forest Science
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    • v.86 no.4
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    • pp.407-414
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    • 1997
  • The resistance of a non-transgenic poplar clone, 'Ogy' and three transgenic poplar lines to the cottonwood leaf beetle, Chrysomela scripta F., was evaluated by in vitro feeding. The lines were transformed with neomycin phosphotransferase II(NPT II) as a selectable marker, proteinase inhibitor II(pin2) as a resistance gene, and CaMV 35S as a promoter. An efficient method of sterilizing the beetle eggs and introducing them into plant tissue cultures was developed. The resistance of the transgenic lines was investigated in terms of effects tin leaf area consumed, insect weight, insect developmental stages, and plantlet root dry weight after feeding. Also, leaf area consumed was examined by leaf age as measured through leaf plastochron index(LPI). The leaf area consumed and insect weight were highly significant between transformants and control, and insect development in vitro was significant among the transgenic lines. Larval infestation was the most severe around LPI 4 to 5 which were young leaves. The system provided a quick, highly controlled method to screen developing transgenic plantlets directly.

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Application of Off-axis Correction Method for EPID Based IMRT QA (EPID를 사용한 세기조절방사선치료의 정도관리에 있어 축이탈 보정(Off-axis Correction)의 적용)

  • Cho, Ilsung;Kwark, Jungwon;Park, Sung Ho;Ahn, Seung Do;Jeong, Dong Hyeok;Cho, Byungchul
    • Progress in Medical Physics
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    • v.23 no.4
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    • pp.317-325
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    • 2012
  • The Varian PORTALVISION (Varian Medical Systems, US) shows significant overresponses as the off-center distance increases compared to the predicted dose. In order to correct the dose discrepancy, the off-axis correction is applied to VARIAN iX linear accelerators. The portal dose for $38{\times}28cm^2$ open field is acquired for 6 MV, 15 MV photon beams and also are predicted by PDIP algorithm under the same condition of the portal dose acquisition. The off-axis correction is applied by modifying the $40{\times}40cm^2$ diagonal beam profile data which is used for the beam profile calibration. The ratios between predicted dose and measured dose is modeled as a function of off-axis distance with the $4^{th}$ polynomial and is applied to the $40{\times}40cm^2$ diagonal beam profile data as the weight to correct measured dose by EPID detector. The discrepancy between measured dose and predicted dose is reduced from $4.17{\pm}2.76$ CU to $0.18{\pm}0.8$ CU for 6 MV photon beam and from $3.23{\pm}2.59$ CU to $0.04{\pm}0.85$ CU for 15 MV photon beam. The passing rate of gamma analysis for the pyramid fluence patten with the 4%, 4 mm criteria is improved from 98.7% to 99.1% for 6 MV photon beam, from 99.8% to 99.9% for 15 MV photon beam. IMRT QA is also performed for randomly selected Head and Neck and Prostate IMRT plans after applying the off-axis correction. The gamma passing rare is improved by 3% on average, for Head and Neck cases: $94.7{\pm}3.2%$ to $98.2{\pm}1.4%$, for Prostate cases: $95.5{\pm}2.6%$, $98.4{\pm}1.8%$. The gamma analysis criteria is 3%, 3 mm with 10% threshold. It is considered that the off-axis correction might be an effective and easily adaptable means for correcting the discrepancy between measured dose and predicted dose for IMRT QA using EPID in clinic.