Multi-modal surface/outline projection and simulation of target/critical tissue movement

Conformal radiotherapy delivers high radiation doses to tumours whilst minimising damage to normal tissues. Therapy planning makes use of treatment simulation and computed tomographic images, which outline gross tumour volume and a dosimetric model. The larger planning target volume includes microscopic disease spread, target motion and set-up errors, effectively determining radiation beam collimation. High energy portal images are used to verify collimation and targeting. Software has been developed to integrate all the above features, allowing clinicians to interactively simulate motion effects and test the robustness of conformal planning. Multi-modality coregistration in 3D enables surface projection of modelled tumour/normal tissue volumes. Projection models are constructed from morphologically defined CT outline frames which are then B-Spline skinned. The biological effects of visualised motion can be explored at near real time rate