Gamma radiation, modulation

The irradiated membranes were then tested in a pilot plant with a plate-and-frame module with capacity for two membranes with an effective area of 90 cm each. Permselective results of irradiated membranes were compared to those of nonirradiated membranes [3]. It was observed that the performance of the samples irradiated with electronic or gamma radiation was very similar to that of the nonirradiated membranes. Tables 32.1 and 32.2 show the results of permeate flux and retention index for gamma- and electron-irradiated membranes, respectively. 

Exposure to natural sources of external ionizing radiation results from the levels of cosmic and terrestrial X and gamma radiation present in the environment. Cosmic radiation at the earth s surface is affected by altitude, geomagnetic latitude, and solar modulation. For example, the dose rate at... 

Fraser, F.C. 1981. Letter to the editor. Mod. Med. Can. 36 1508. Gupta, M.L., P.K. Agrawala, P. Kumar, et al. 2008a. Modulation of gamma radiation-inflicted damage in Swiss albino mice by an alcoholic fraction of Podophyllum hexandrum rhizome. J. Med. Food ll(3) 486-492. 

From a technical point of view, intensity-modulated radiation therapy (IMRT) optimizes several parameters selection of multiple beams and, for each beam, optimization of dose, dose rate, size and shape, etc. Tomotherapy optimizes the dose distribution by IMRT in successive sections with immediate verification gamma knife, cyberknife, and radiosurgery concentrate high radiation doses in well-defined small volumes. 

Powerful irradiation techniques are now available or under development for photons intensity-modulated radiation therapy (IMRT), tomotherapy, gamma knife, cyberknife, radiosurgery, etc. These techniques make it possible to irradiate any volume of any complex shape with minimum irradiation of critical normal structures. 

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