hrvatski

Određivanje apsorbirane doze u radioterapiji širokim snopovima 60Co gama zračenja

Radiation in radiotherapy has selective impact on ill and healthy tissue. During the therapy the healthy tissue receives certain amount of dose. Therefore dose calculations in outer radiotherapy must be accurate because too high doses produce damage in healthy tissue and too low doses cannot ensure efficient treatment of cancer cells. A requirement on accuracy in the dose calculations has lead to improvement of detectors, and development of absolute and relative dosimetry. Determination of the dose distribution with use of computer is based on data provided by the relative dosimetry. This paper compares the percentage depth doses in cubic water phantoms of various dimensions with percentage depth doses calculated with use of Mayneord factor from the experimental depth doses measured in water phantom of large dimension. Depth doses in water phantoms were calculated by the model of empirical dosimmetrical functions. The calculations were based on the assumption that large 60Co photon field exceeds the phantom?s limits. The experimental basis for dose calculations by the model of empirical dosimmetrical functions were exposure doses measured in air and dose reduction factors because of finite phantom dimensions. Calculations were performed by fortran 90 software. It was found that the deviation of dosimmetric model was small in comparison to the experimental data.

apsorbirana doza; 60Co; radioterapija; ekspozicijska doza; doziimetrijska funkcija

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