Light it Up: LSU ECE Professor Explores Fluorescence Dental Imaging

Xu posing with cone beam cameraBATON ROUGE – The Centers for Disease Control and Prevention estimates that nearly 85 percent of children and 63 percent of adults in the United States visit the dentist each year. Most, if not all, of these patients receive X-ray imaging at least once a year. Realizing the harm that X-rays can have on patients who need dental care throughout their lives, LSU Electrical and Computer Engineering Assistant Professor Jian Xu is creating a safer approach using near-infrared (NIR) imaging.

“My research has very good benefits that almost anyone can understand,” said Xu, who received his PhD from Yale University and specializes in biomedical instrumentation, bio-nano electronics, image-guided surgery, and biomedical imaging. “It touches the everyday life of most of us.”

Through a Leverage Innovation for Technology Transfer (LIFT2) grant, Xu is able to research tooth abnormalities that require a great deal of X-ray imaging, which exposes patients to ionizing radiation. This radiation involves atoms in living cells becoming ionized, leading to one of three things—the cell dies, the cell repairs itself or the cell mutates incorrectly and becomes cancerous.

X-ray imaging techniques, such as 2D X-rays and computed tomography (CT), are widely used in dental clinics and release this harmful radiation. Cone beam CT (CBCT), specifically, is used to provide information on a diagnosis of impacted teeth before surgery, but the ionizing radiation levels are 3-44 times higher than 2D imaging.

“Ionized radiation has two side effects,” Xu said. “One is called a stochastic. The other is called a non-stochastic. The stochastic effects include induction of cancer, mental retardation (e.g., Down Syndrome), and genetic effects. The non-stochastic effects include cataracts, skin erythema, hemopoietic syndrome, and sterility.

“A stochastic effect means it doesn’t have a threshold. As long as it’s non-zero, it’s going to be harmful, as pointed out by the U.S. National Academy of Sciences Biological Effects of Ionizing Radiation Committee and French Academy. Children are especially vulnerable since they receive three to six times more dental X-rays than adults due to rapid tooth growth and tooth decay.”

Due to its safety, high contrast and sensitivity, affordable cost, and easy-to-use approach, Xu and his team are experimenting with NIR imaging, particularly fluorescence imaging.

This type of imaging uses indocyanine green (ICG), a dye that has been approved by the U.S. Food and Drug Administration and the European Medicines Agency. It is known to produce NIR fluorescence that can be used as a photosensitizer dye for the reduction of bacterial load in periodontal pockets or as a photo-absorbing dye for selective removal of decayed enamel. Though the powder appears green, its fluorescence can only be seen using an NIR camera.

Through his experimentation, Xu has found that the endoscopic dental imaging can serve as an efficient alternative tool for diagnosing dental diseases and disorders in humans in real time.

“Even dentists are very interested in this new, safer technique,” Xu said. “As a patient, you only do this imaging about twice a year, but dental technicians must operate these machines every day. They are also concerned about ionized radiation.”

Xu hopes to not only make dental imaging safer, but to also teach his students to question everything.

“I designed a course at LSU called Imaging Applications and Techniques,” Xu said. “I make sure to amplify the pros and cons of different medical imaging so the next time you go to the hospital, you are not just blindly trusting what you are told.”

Learn more about Xu’s research, which is on the June cover of Annals of The New York Academy of Sciences, by clicking here.

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 Contact: Libby Haydel

Communication Specialist