نتایج جستجو برای: dose fractionation
تعداد نتایج: 327985 فیلتر نتایج به سال:
BACKGROUND A variety of hypofractionated radiotherapy schedules has been proposed after breast conserving surgery in the attempt to shorten the overall treatment time. The aim of the present study is to assess acute and late toxicity of using daily fractionation of 2.25 Gy to a total dose of 45 Gy to the whole breast in a mono-institutional series. METHODS Eighty-five women with early breast ...
Risks of noncancer causes of death, particularly cardiovascular disease, associated with exposures to high-dose ionizing radiation, are well known. Recent studies have reported excess risk in workers who are occupationally exposed to low doses at a low dose rate, but the risks of moderately fractionated exposures, such as occur during diagnostic radiation procedures, remain unclear. The Canadia...
The present work was designed to study the antioxidant activity and to identify the main active components of the essential oil of ajowan (Trachyspermum copticum) fruit. GC and GC-MS analyses of the essential oil showed the presence of eight compounds. The main constituents of the oil were thymol (43.7%), p-cymene (26.8%), and γ-terpinene (24.9%). The antioxidant and free radical scavenging act...
In this study we defined the pharmacodynamic parameter that optimizes outcome in deep-seated Candida albicans infections treated with fluconazole. Using a murine model of systemic candidiasis, we conducted single-dose dose-ranging studies with fluconazole to determine the dosage of this drug that resulted in a 50% reduction in fungal densities (50% effective dose [ED50]) in kidneys versus the f...
The cell cycle dependence of radiation-induced apoptosis was measured using mitotically synchronized REC:myc(ch1) and Rat1:mycb cells. Cells in S and G2 phases were more susceptible; the apoptotic fraction was about 0.7-0.8 as compared to about 0.4 for G1 cells at a dose of 10 Gy. Two-dimensional cytofluorimetric analysis of cells, pulsed-labeled with bromodeoxyuridine and then irradiated with ...
Phase sensitive x-ray imaging expands the applicability of standard attenuation based techniques by offering several orders of magnitude of increase in sensitivity. Due to the short wavelength, x-ray phase is not directly measurable, but has to be put in evidence by the use of phase contrast techniques. The phase can then be reconstructed from one or several phase contrast images. In this study...
The standard formulation of the fractionation problem with multiple organs-at-risk based on the linear-quadratic dose-response model requires the solution of a nonconvex quadratically constrained quadratic program. Existing literature therefore uses heuristic methods without any analyses about solution quality. There is no known method that is guaranteed to find an optimal solution. We prove th...
Radiotherapy is crucial and substantially contributes to multimodal cancer treatment. The combination of conventional fractionation radiotherapy (CFRT) and systemic therapy has been established as the standard treatment for many cancer types. With advances in linear accelerators and image-guided techniques, high-dose fractionation radiotherapy (HFRT) is increasingly introduced in cancer centers...
Here it is mathematically shown that the Linear Quadratic model insuffcient to adequately describe survival curve of some cell lines, and β parameter this dependent on dose range used for fitting. Therefore, higher-order polynomials are needed have a single formula describes all lines at ranges. Based Taylor series two mathematical hypotheses, possible show free parameters each other. A new app...
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