"In 2004, more than 80,000 endocrine surgeries were performed in the United States and this number is projected to grow to more than 100,000 by 2020. Today, when a surgeon cuts into a patient’s neck to remove a diseased thyroid, somewhere between 8 to 19 percent of the time the patient’s parathyroid glands are also damaged or removed.
The parathyroid glands – four small organs the size of grains of rice located at the back of the throat – glow with a natural fluorescence in the near infrared region of the spectrum.
This unique fluorescent signature was discovered by a team of biomedical engineers and endocrine surgeons at Vanderbilt University, who have used it as the basis of a simple and reliable optical detector that can positively identify the parathyroid glands during endocrine surgery."
http://news.vanderbilt.edu/2011/06/parathyroid-glow/