Visualization of 4D Computed Tomography Datasets

Organ motion is problematic when employing radiation therapy to treat certain types of cancers. Motion problems are commonly encountered when treating lung, thorasic, and liver cancers, since patients breathe during treatment. To begin to address this issue, clinical researchers in the Radiation Physics Division at Massachusetts General Hospital have developed 4-D computed tomography (CT) imaging (the four dimensions being height, width, depth, and time). This new imaging technology provides clinicians with far more precise information on tumor motion with which to plan and administer radiation therapy. To aid radiologists and doctors, we have developed a visualization browser and supporting toolkit that allows for volume rendering of 4-D CT images. Included in this toolkit is the ability to simulate any amount of radiation dosage specified by the user. In our most recent enhancements to the toolkit, we have expanded its capabilities to create a fully-navigable 3D rendering model. We have developed this toolkit using SCIRun, a problem-solving environment specifically designed for visualization and modeling of complex scientific problems. Using SCIRun's visualization tool (Biolmage), we are able to render 4-D models based on CT scans. This paper describes our present efforts developing this capability, and discusses some of the features provided by the toolset