engleski

Comparison of four models for calculation of collimator scatter factors of lina cphoton beams

Two approaches for aproximation of collimator scatter correction factors of rectangular fields can be found in recent publications. One is based on empirical equations or some more sophisticated physical methods using certain parameters which have to be adjusted for a specific machine. The other is based on idea of decomposition of collimator scatter correction factor of two variables - into the product of two functions of one variable. In this work four models, based on decomposition are compared. The measurements were carried out using nominal 6MV and 15 MV photon beams of a Siemens Mevatron MD2 and Varian Clinac 1800 accelerators. It was shown that better approximation can be achieved with a suitable choice of basic measurements and normalisation data.

radiotherapy; collimator scatter; photon

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