A More Complete Picture of Intraocular Tumors

Guan Xu, Ph.D.

To properly diagnose and treat cancer, it is essential to understand not only the physical characteristics of a tumor, but also its molecular and chemical properties. This presents a particular challenge for tumors in hard-to-reach spots or where traditional tissue biopsy is impractical, like inside the eye.

Diagnosis of intraocular tumors mainly requires noninvasive imaging technologies like optical coherence tomography and ultrasound. While these tools show the tumor’s structural characteristics, they don’t reveal key molecular and chemical properties.

A multidisciplinary Michigan Medicine team including new Kellogg assistant professor Guan Xu, Ph.D., is addressing the limitations of current imaging modalities with a new hybrid technology called photoacoustic imaging (PAI).

As its name implies, PAI combines useful properties of both light (photo) and sound (acoustic) waves. A laser inserted through a fine needle endoscope illuminates an area of tissue. As the tissue absorbs the light energy and converts it to heat, it generates high-frequency waves that reveal its structural characteristics. At the same time, the tissue projects some of the absorbed infrared light as a different light form that provides information about the tissue’s chemical properties.

PAI can potentially be used to image tumors anywhere in the body. Dr. Xu, who is also an assistant professor of biomedical engineering, has demonstrated its ability to characterize several tissue types in mice. His application of PAI to prostate cancer has been recognized with a prestigious NIH Method to Extend Research in Time (MERIT) award. At Kellogg, he will focus on refining the use of PAI to diagnose and direct treatment for intraocular tumors.