Night Vision, Laser Imaging Enhance Lymphatic Studies

Better imaging of the lymphatic system is now possible using IR techniques, allowing earlier detection of cancer and lymphedema. It could also lead to more effective, manageable treatment of such diseases.

A new technology, developed by a team from the University of Texas Health Science Center at Houston (UTHealth) Medical School, is able to image the human lymphatic system in real time without the need for radioactive compound injections.

Near-infrared fluorescence image of lymphatics in the lower leg of a subject with lymphedema. Courtesy of John Rasmussen, UTHealth.

The near-infrared fluorescence lymphatic imaging (NIRFLI) device quantitatively measures lymphatic structures and flow throughout the lymphatic system, even in the tiniest of lymph vessels.

This is an improvement over the existing lymphoscintigraphy method, the researchers said, which is less efficient, more invasive and time-consuming. It can only image large lymphatic vessels, not the smaller, fine ones, and cannot do so in real time.

The new device visualizes the lymphatic capillaries in concert with indocyanine green dye that is injected in small doses into the patient’s skin. This is absorbed into the lymphatic system and fluoresces when illuminated by a laser diode. The fluorescent light is then amplified by military-grade night vision technology.

A CCD digital camera captures the images, and from those, movies showing flow within the lymphatic system are created.

“From these images and movies, we can identify abnormal lymphatic structure and function in a variety of diseases and disorders in which the lymphatics play a role,” said John Rasmussen, a scientist at UTHealth.

The NIRFLI technology could also soon diagnose lymphedema and better monitor treatment, Rasmussen said. Additionally, it could assist surgeons in more efficiently identifying and removing lymph nodes in cancer patients. “I think we have barely scratched the surface of what is possible,” he said.

The research was funded by National Institutes of Health.

For more information, visit www.uth.edu.