Warp assisted tumour and target volume visualisation in radiation therapy

This paper describes warp assisted tumour delineation from the images in a CT scan sequence, and the first algorithm to realistically close the tumour volume prior the automated generation of the larger planning target volume, on which a cancer patient´s radiotherapy treatment is based. Space variant dilation, driven by box-guides indicating multiple expansion vectors in a single operation, is introduced. The algorithms were first tested in clinical trials studying dose escalated prostate cancer treatment. Results are presented to show that the techniques provide the capability to delineate and close a tumour volume in a manner that reflects natural asymmetries at the volume extrema and in a distance/distances that is/are under the control of the clinical user. Space variant dilation is shown to be practical using a minimum of knowledge concerning tumour motion and anatomical constraints.