Visualization of 4D CT-Scan 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 3-D 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 (BioImage), 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.

Status: Completed in May 2006

Papers Published

Dedual, N., Johnson, B., Chen, G. Visualization of 4D Computed Tomography Datasets, IEEE Southwest Symposium on Image Analysis and Interpretation, 2006

Folkert, M., Dedual, N., Chen G., A Biological Lung Phantom for IGRT Studies, Medical Physics – June 2006 – Volume 33, Issue 6, p. 2234

Images

This is a false color image of a patient’s brachial tree (pink), along with the spinal cord (green).

Another false color image, this one shows in greater detail the lung structure of a patient.

Movies

3D Visualization

3D Visualization of part of a lung – 2005 from Nicolas Dedual on Vimeo.

In this movie, we’re able to see the lungs animate as the camera rotates back and forth from a Superior Anterior-Posterior position to a complete Anterior-Posterior position.

3D Visualization of a Lung – Detailed – 2005 from Nicolas Dedual on Vimeo.

This video provides a more detailed visualization of a patient’s lung structure. We are also able to see the outline of the tumor on the patient’s right lung before we decided to switch rendering modes in order to isolate the tumor in our volumetric renderings.

3D Dose Visualization

Visualization of 3D radiation dose treatment from Nicolas Dedual on Vimeo.

In this movie, we were able to generate a simulated dose treatment plan and overlay it over a patient’s volumetric visualization, in order to determine which areas would be more affected. The radiation is rendered from low (blue) to high (red).