The hybrid X-ray/optical imaging system relies on nanosize phosphors imaging markers that convert X-ray energy to light. The markers are made of gadolinium oxysulfide and coated with either terbium (glows green) or europium (glows red).
In laboratory tests, the hybrid system showed a 260 percent contrast difference between simulated normal and cancerous tissue, the researchers report. A standard X-ray showed a 0.6 percent contrast difference.
The team also found that very low concentrations of the nano-phosphors produce high contrast pictures. "We have determined that the minimum detectable concentration is far lower than conventional contrast enhanced X-ray imaging, for the same dose, meaning that tumors may be detected at the earliest, most treatable stage," says lead author Colin Carpenter, a Stanford postdoctoral fellow.
The system could aid both drug discovery and disease treatment. For example, attaching the phosphors to certain biomarkers would help researchers better visualize the distribution and efficacy of new anti-cancer drugs, says Carpenter.
"However, in my mind, the most exciting application for this system is a device to aid surgeons in the complete excision of diseased tissue," he adds. "Currently, it is very difficult to remove all the tumor cells in the tissue, because surgeons don't have a tool that is sensitive enough. Allowing a real-time visualization of these tumor cells could significantly improve treatment."
The presentation "Development of an X-ray/Optical Luminscence Imager for Improved X-ray Contrast Sensitivity" by CM Carpenter et al. will be at 4:00 p.m. on Wednesday, July 21 in 204B of the Philadelphia Convention Center.
|Contact: Jason Socrates Bardi|
American Institute of Physics