Dose surface maps as a tool to predict toxicity after radiotherapy for cervical cancer patients
Master thesis
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http://hdl.handle.net/11250/2615581Utgivelsesdato
2017Metadata
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Sammendrag
Cervical cancer is one of the leading cancer types for women, both in incidence and mortality. The standard treatment for cervical cancer is brachytherapy and external beam radiotherapy in combination with chemotherapy. Utilizing modern image guided adaptive radiotherapy has improved local control and survival for cervical cancer patients. However, many women who survive cervical cancer experience treatment related side effects of the vagina. In order to minimize the risk of treatment related toxicity, dose effect predictors for the vagina need to be established.
In this thesis a tool for producing dose-surface maps for the vagina has been developed using Interactive Data Language (IDL). This tool has been tested on ten cervical cancer patients from the EMBRACE study which have all been treated with brachytherapy and external beam radiotherapy. The dose-surface maps have been successfully generated for each of the four brachytherapy fractions, followed by a summation of both brachytherapy and external beam radiotherapy doses using conversion to 2 Gy equivalent doses using $\frac{\alpha}{\beta}$ = 3 Gy for the vagina. A few parameters for toxicity prediction were extracted from the dose-surface-maps and tested on the reported vaginal toxicity for the ten patients.
This method for reporting vaginal dose coming from external beam radiotherapy and brachytherapy gives representative information on the dose along the surface of the vagina. It allows for summation of both brachytherapy fractions and external beam radiotherapy fractions. Large variations in dose distribution both inter-fractionally and intra-fractionally was observed, and no clear toxicity correlation was found for the parameters extracted from the dose-surface maps in this thesis.