Researchers using virtual imaging to show real-time organ motion
Researchers from Rensselaer Polytechnic Institute in Troy, N.Y. are developing a physics-based virtual model that can simulate a patient’s breathing in real time. When used in conjunction with existing 3D models, the researchers believe that adding the fourth dimension of time could significantly improve the accuracy and effectiveness of radiation treatment for lung and liver cancers. The work is being done with support of a $2 million grant from the National Institutes of Health (NIH).

“Live patients are not static beings, and a moving organ such as the lung or heart is a main concern in radiation treatment or imaging of tumors that are affected by such organ movement,” said George Xu, professor of nuclear and biomedical engineering. “In order to determine accurate and effective radiation dosages, doctors must consider such issues as the breathing function and air volume change that are affected by several physiological factors over the course of the radiation treatment.”

The work is being done as part of a multidisciplinary collaboration with clinical colleagues at the Cancer Therapy & Research Center in San Antonio, Texas, to develop the 4-D Visible Photographic Man (VIP-Man).

Real-time simulations could allow doctors to spot the small fractions of time when the lungs, liver, kidneys, and eventually the heart, are stationary relative to the external radiation beams. These opportune moments during the actual therapy mean that doctors will have more confidence delivering the radiation to a moving tumor.

“The 4-D VIP-Man will allow doctors and medical physicists to accurately predict and monitor these anatomical changes to provide the most effective treatment possible at any given time,” Xu said.

Suvranu De, associate professor of mechanical engineering is collaborating with Xu. De said that “using advanced computational tools, it is possible to simulate lung movement; however, not in real time. For effective radiation therapy, physics-based real-time performance offers the ultimate solution.”

The key challenge in this project is to develop the algorithms that will make the virtual lungs and adjacent tissues move in real time according to realistic tissue biomechanical properties, De said.

Xu expects that the physics-based 4-D VIP-Man will eventually be used as a more general anatomical modeling tool for the biomedical community to help patients with respiratory and cardiac diseases.

A video of a moving lung model can be downloaded here: