RESUMO
A method, developed from the Quantisation Method, of calculating dose-rate distributions around uniformly and nonuniformly loaded brachytherapy sources is described. It allows accurate and straightforward corrections for oblique filtration and self-absorption to be made. Using this method, dose-rate distributions have been calculated for sources of radium 226, gold 198, iridium 192, caesium 137 and cobalt 60, all of which show very good agreement with existing measured and calculated data. This method is now the basis of the Interstitial and Intracavitary Dosimetry (IID) program on the General Electric RT/PLAN computerised treatment planning system.
Assuntos
Braquiterapia/métodos , Modelos Teóricos , Dosagem Radioterapêutica , Radioisótopos de Césio/uso terapêutico , Radioisótopos de Cobalto/uso terapêutico , Radioisótopos de Ouro/uso terapêutico , Humanos , Irídio/uso terapêutico , Radioisótopos/uso terapêutico , Rádio (Elemento)/uso terapêuticoRESUMO
A method for performing inhomogeneity corrections using a generalised Batho equation is described. The corrections are performed using the quantitative anatomical data produced by a CT scanner. The generalised Batho equation has been implemented on an EMIPLAN 7000 interactive treatment planning system. Details are given of the acquisition of the required data from the CT scan and from the existing stored beam data of the therapy machines.
Assuntos
Radioterapia/métodos , Tomografia Computadorizada por Raios X/métodos , Computadores , MatemáticaRESUMO
Techniques by which the quantitative anatomical data inherent in a CT scan can be directly used in treatment planning are described. The correction algorithms used in the RAD-8 system, based on an effective path length, have been extended to a pixel-by-pixel approach. By calibrating the X-ray transmission CT scanner in terms of electron densities (electron cm-3) inhomogeneity corrections may be made automatically.
