41. Estimation of dose distrubution according to dose volume histograms (DVH) in conformal radiotherapy

Abstract

Aim

The evaluation what kind of statistical informations concomitant with DVH are essential in estimations of dose distribution in conformal planning of radiotherapy.

Method

Un the base of test case – cancer of the base of tongue, irradiation plans for different sizes of irradiation boost field margins were analysed. DVHs-differential and cumulative for selected critical organs and target volume have been accounted. On base of standard deviation and minimal doses in select volumes target and critical tissues have been estimated. Then probability of local control the risk of complications have been expected.

Results and discussion

The modelled results show, that graphic representation of DVH is not sufficient information itself in estimation of dose distribution. Statistical parameters like modal dole, standard deviation determine essential supplement of graphic dose distribution. Especially standard deviation contains indispensable information. The histogram differential and cumulative should be used together for estimations of dose distribution. It appears that estimation of dose distribution in target volume should be based on cumulative histogram and estimation of dose distribution in critical organs – on differential histogram.