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AbstractAbstract
[en] Purpose: Pelvic box fields in prone position are the standard treatment for patients with cervical carcinomas. The issue investigated in this report is whether this technique should also be used when extending the planning target volume to the paraaortic region. Materials and methods: In a prospective study of eight consecutive patients with cervical carcinomas, two patient positions (prone and supine) and three radiation techniques (A, anteroposterior/posteroanterior opposed fields; B, four-field box; and C, three-field technique) were examined concerning the dose to critical organs. The analysis was based on three-dimensional planning, dose-volume histograms and normal tissue complication probabilities (NTCP). Results: Compared to the prone position, the supine position led to improved organ sparing in four of seven organs (liver, both kidneys, spinal canal). In two of seven organs (rectum and bladder) no difference between prone and supine position was observed. The best sparing of small bowel was achieved in prone position. Technique B followed by technique C in the supine position resulted in the best overall sparing of critical organs concerning the volumes receiving the respective TD5/5 doses or more. Mean NTCP values for liver, rectum and bladder were below 1.0%. The highest values of up to 12% were found for both kidneys in prone position with C and for the spinal canal with A in the prone and supine position. Conclusion: According to this analysis, for the treatment of the pelvic and paraaortic lymph node regions together, supine position and technique B (alternatively C) should be preferred despite the advantages of prone position on belly boards for pelvic irradiation alone
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S016781400300080X; Copyright (c) 2003 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] Background and purpose: The intention of this prospective study is to assess the influence of different patient positionings and the use of belly boards on the coverage of the uterus by standard radiation fields. Material and methods: In 21 women with carcinoma of the uterine cervix magnetic resonance imaging (MRI) scans in prone patient position with and without belly board and computed tomography (CT) scans in supine position were analysed after superimposing standard pelvic box fields. Further, all patients underwent a second MRI field control in prone position with belly board to detect intraindividual variations in the uterus position during treatment. Results: Standard portals did not completely cover the uterus in supine position in 7/21 (33%), in prone position with belly board in 7/21 (33%) and without belly board in 5/21 (24%). Insufficient uterine coverage was found only in the anteroposterior direction. The mean distance (± standard deviation) between the field borders of the lateral portals and the uterus was in supine position anteriorly 3.4 cm (±2.2 cm) and posteriorly 1.8 cm (±1.3 cm), in prone position with belly board anteriorly 2.2 cm (±2.7 cm) and posteriorly 2.6 cm (±1.6 cm), prone without belly board anteriorly 3.3 cm (±2.4 cm) and posteriorly 1.9 cm (±1.1 cm). The difference was statistically significant between supine and prone position with belly board and between prone position with and without belly board. Repeated MRI controls during therapy showed no significant changes compared to the MRIs at the beginning of therapy. Conclusions: The use of standard radiation fields results in a high percentage of geographical misfits. Three-dimensional treatment planning is a prerequisite for adequate uterus coverage
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S0167814001004716; Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] Deviations between simulation and first check films were quantitatively assessed for 95 unselected head and neck cancer patients. All measured deviations -- calculated on the basis of a total of 190 simulation and 380 verification films -- were normally distributed, with mean values of 0-3 mm and standard deviations of 3-5 mm. Of the absolute deviations, 50% and 95% were within 3 mm and 9 mm, respectively. These results should be considered in clinical practice when prescribing safety margins and adequate cut off doses for sparing critical organs in head and neck cancer
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Copyright (c) 1995 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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AbstractAbstract
[en] Background and purpose: There is growing evidence in recent years that the antiproliferative effects of ionizing radiation may not be exclusively mediated via DNA damage but also by interactions and alterations of cell membrane associated processes. Here, we tested the hypothesis that membrane active cytotoxic ether lipids and analogues may interact with ionizing radiation, enhancing its anti-proliferative effects. Materials and methods: The two epithelial tumor cell lines HTB 43 and KB, and the ether lipid resistant subline KBr were treated by a combination of radiation and ether lipids. Cytotoxic effects were measured by colony forming assays and the effects on membrane phospholipids were determined by quantitative thin-layer chromatography of cell lipid extracts. Results: We present evidence that some ether lipids show supra-additive cytotoxic effects with ionizing radiation. These effects seem to depend on the same structural properties of ether lipids that determine their intrinsic cytostatic and cytotoxic activity. Identical growth inhibitory results were achieved when cells were treated before, or 30 min after irradiation. Analysis of major membrane phospholipids revealed no statistically significant differences of phospholipid distribution pattern in cells exposed to both treatment modalities. Conclusion: Our data indicate that changes of overall membrane phospholipid composition do not seem to be the mechanism of synergistic antiproliferative activity of ether lipids and ionizing radiation
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S0167814097019099; Copyright (c) 1997 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: Egypt
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AbstractAbstract
[en] Purpose: Primary malignant rhabdoid tumor (MRT) of the central nervous system is an extremely aggressive tumor predominantly related to early childhood, with characteristic histopathological findings but unclear histogenesis. Owing to its low incidence, little knowledge exists concerning the best therapeutic strategy. Methods and Materials: Three children of our hospital with MRT of the brain underwent a maximum tumor resection followed by multidrug chemotherapy and radiation therapy to the craniospinal axis. Results: Relapse was disseminated along the spinal subarachnoid spaces in one child and occurred at the primary tumor site in the other two patients. Maximum survival was 15 months from diagnosis. Conclusion: A review of patients reported in the literature and a comparison to our patients reveals a high propensity to early local relapse and meningeal dissemination. In the absence of more effective therapeutic options, we recommend multidisciplinary treatment of patients in good general condition and with resectable disease. In particular, following radiation therapy, tumor remissions and delay of tumor regrowth have been observed
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S0360301698001060; Copyright (c) 1998 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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International Journal of Radiation Oncology, Biology and Physics; ISSN 0360-3016; ; CODEN IOBPD3; v. 41(5); p. 1013-1019
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AbstractAbstract
[en] Purpose: To define the maximum tolerated dose (MTD) by describing the dose-limiting toxicity (DLT) of weekly paclitaxel (PAC) given as a 1-h IV infusion in patients with head and neck cancer concomitant to irradiation. Methods and Materials: Patients with unresectable or incompletely resected head and neck cancer were enrolled into a prospective, dose-escalating Phase I study. Toxicity was graded according to the WHO toxicity score. MTD dose was defined when two out of six patients developed DLT. The starting dose of PAC was 20 mg/m2 once weekly IV over 60 min, with a subsequent dose escalation of 10 mg/m2 in cohorts of three new patients. Radiation therapy was administered in three field technique over 6-7 weeks in 2.0 Gy/daily fractions for 5 consecutive days/week up to total doses of 60-70 Gy. Results: >From 1994-1996, 18 patients completing three dose levels were included into the study. Altogether, 101 courses of chemotherapy were evaluable for toxicity. On the second dose level (30 mg/m2) one of three patients experienced DLT with Grade IV mucositis. On the next dose level with 40 mg/m2 PAC weekly one patient experienced DLT being prolonged Grade III mucositis. From the following three patients required, two patients showed no DLT. The third patient showed mucositis of WHO Grade 4 and died from hemorrhage caused by a rupture of the a pharyngeal wall. Dose level 2 (30 mg/m2) was repeated and one of the three newly treated patients again suffered from mucositis WHO Grade 4. Conclusion: When PAC is given weekly as a 1-h infusion concomitant to radiotherapy, MTD is 30 mg/m2 with mucositis being DLT; hematological and further non hematological toxicity is mild
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S0360301697001168; Copyright (c) 1997 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: Argentina
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International Journal of Radiation Oncology, Biology and Physics; ISSN 0360-3016; ; CODEN IOBPD3; v. 38(4); p. 691-696
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Weiss, Elisabeth; Krebeck, Michael; Koehler, Brunhild; Pradier, Olivier; Hess, Clemens F., E-mail: eweiss@med.uni-goettingen.de2001
AbstractAbstract
[en] Purpose: To investigate whether the standardized helmet technique adequately covers the cribriform plate. Methods and Materials: For 11 patients with acute leukemia or primary intracerebral neoplasms undergoing irradiation with the standardized helmet technique, three-dimensional isodose distributions were evaluated with special respect to the dose to the cribriform plate and the ocular lenses. Results: The average dose received by 95% of the cribriform plate with the standardized helmet technique was 85% of the prescribed dose. To enclose the cribriform plate by the 95% isodose (according to the ICRU 50 report) with a 10-mm safety margin allowing for deviations during treatment planning and delivery, the eye block had to be moved in the ventrocaudal direction with an average vector length of 13.6 mm. Consequently, the mean dose received by 5% of the lenses rose from 18% to 91% of the prescribed total dose. Conclusion: Sufficient lens shielding is usually not compatible with safe irradiation of the frontobasis by the standardized helmet technique
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S0360301600015480; Copyright (c) 2001 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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International Journal of Radiation Oncology, Biology and Physics; ISSN 0360-3016; ; CODEN IOBPD3; v. 49(5); p. 1475-1480
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AbstractAbstract
[en] Purpose: The combined effect of natural Interferon-beta (n-IFN-β) and ionizing radiation was tested in vitro on 5 different tumor cell lines and 1 embryonal lung fibroblast cell line. Materials and Methods: The following cell lines were used: A549 (lung cancer), MCF-7 (breast cancer), CaSki (cervical cancer), WiDr (colon cancer), ZMK-1 (head and neck cancer), and MRC-5 (embryonal lung fibroblast line). Cells were incubated with n-IFN-β (30 I.U./ml to 3000 I.U./ml) 24 h before irradiation. Irradiation was given as single dose between 1 and 6 Gy. Cell survival was evaluated using a standard colony-forming assay. Results: Incubation with n-IFN-β enhanced the effect of radiation in all tumor cell lines tested. The maximum sensitizing enhancement ratios (SER) at the 37% survival level were: 1.66 for A549 cells, 1.47 for CaSki cells, 1.56 for MCF-7 cells, 1.40 for WiDr cells, and 1.57 for ZMK-1 cells. In the nonneoplastic MRC-5 cell line, no radiosensitizing effect of n-IFN-β could be demonstrated. The linear quadratic fit of the survival curves showed an increase of the α-component for all tumor cell lines treated with n-IFN-β. Conclusions: IFN-β enhanced the effect of radiation in the tumor cell lines, but not in the nonmalignant lung fibroblasts. The increase of the α component in the survival curves indicates that impaired radiation repair or the accumulation of sublethal damage might play a role for the radiosensitizing effect of n-IFN-β
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S0360301698004118; Copyright (c) 1999 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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International Journal of Radiation Oncology, Biology and Physics; ISSN 0360-3016; ; CODEN IOBPD3; v. 43(2); p. 405-412
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ANIMAL CELLS, BODY, CONNECTIVE TISSUE CELLS, DIGESTIVE SYSTEM, DISEASES, DOSES, DRUGS, GASTROINTESTINAL TRACT, GLANDS, GROWTH FACTORS, INTESTINES, LYMPHOKINES, MEDICINE, MITOGENS, NEOPLASMS, NUCLEAR MEDICINE, ORGANIC COMPOUNDS, ORGANS, PROTEINS, RADIOLOGY, RESPIRATORY SYSTEM, RESPONSE MODIFYING FACTORS, SOMATIC CELLS, THERAPY
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Hermann, Robert Michael; Pradier, Olivier; Lauritzen, Katharina; Ott, Marcel; Schmidberger, Heinz; Hess, Clemens F., E-mail: ro.hermann@t-online.de2002
AbstractAbstract
[en] Purpose: To show the results of treating posterior uveal melanomas with 106Ru plaque β-ray radiotherapy and to review and discuss the literature concerning the optimal apical dose prescription (100 vs. 160 Gy). Methods and Materials: Forty-eight patients with uveal melanomas (median height 3.85 mm + 1 mm sclera) were treated with ruthenium plaques. The median apical dose was 120 Gy, the median scleral dose 546 Gy. Results: After 5.8 years of follow-up, the overall 5-year survival rate was 90%, the disease specific 5-year survival rate was 92% (3 patients alive with metastasis). Six percent received a second ruthenium application, 10% of the eyes had to be enucleated. Local control was achieved in 90% of the patients with conservative therapy alone. Central or paracentral tumors showed 50% of the pretherapeutic vision after 4 years, and 80% of the vision was preserved in those with peripheral tumors. The main side effects were mostly an uncomplicated retinopathy (30%); macular degeneration or scarring led to poor central vision in 30% of cases. Conclusion: Brachytherapy with ruthenium applicators is an effective therapy for small- and medium-size posterior uveal melanomas. Our results are comparable to other series. The treatment outcome does not seem to be capable of improvement by increasing the apical dose. An internationally accepted model for defining the dosage in brachytherapy is needed
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S0360301601027638; Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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International Journal of Radiation Oncology, Biology and Physics; ISSN 0360-3016; ; CODEN IOBPD3; v. 52(5); p. 1360-1366
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AbstractAbstract
[en] Purpose: To assess uncertainties in the definition of the clinical target volume (CTV) for patients scheduled for primary radiotherapy of cervix carcinoma. Methods and materials: Seven physicians (five radiation oncologists and two gynaecologists) independently contoured the CTVs for three patients. All observers were provided with the same clinical information. CTVs were entered directly in the treatment planning system. Differences were analysed qualitatively and quantitatively. Results: The qualitative analysis revealed a good agreement by all observers on anatomical structures identified to be at risk for tumour spread. Quantitatively, however, a large interobserver variability was found. The ratio between largest and smallest volumes ranged between 3.6 and 4.9 for all observers (3.6-4.9 for the radiation oncologists, 1.3-2.8 for the gynaecologists). The median three-dimensional difference in gravity centres ranged between 10.9 and 26.3 mm for the respective patients. The ratio of common volumes to encompassing volumes ranged between 0.11 and 0.13 for the radiation oncologists, and between 0.30 and 0.57 for the gynaecologists. Conclusions: Although there was a good consistency in outlined anatomical structures, for the radiation therapy of carcinomas of the uterine cervix a large interobserver variability in CTV delineation concerning the magnitude and relative location of volumes was observed. Compared to other factors, e.g. set-up and organ motion, interobserver variability in CTV definition seems to have the highest impact on the geometrical accuracy in the radiotherapy of this tumour entity
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S0167814002003730; Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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