Rensselaer Researchers Seeing Farther and Faster with Terahertz (THz) Imaging
Troy, N.Y. — Xi-Cheng Zhang, the J. Erik Jonsson ’22
Distinguished Professor of Science at Rensselaer Polytechnic
Institute, and a team of researchers are the first to image
biological tissue using single pulses of terahertz (THz or
T-ray) radiation. This single-pulse approach will improve
diagnostic time from hours or days, down to minutes or seconds.
The technique could one day lead to computerized medical
diagnoses right in the physician’s office.
Zhang and his colleagues combined T-rays — those that are
within the far-infrared region of the electromagnetic spectrum
— with a new technique that delivers single-picosecond-long
“blasts” or “chirped pulses” of light. Using a single pulse of
THz radiation that is only a few picoseconds long allows for
better and faster imaging results in biological tissue.
The unique properties of THz radiation allow it to “see”
farther, and in more detail, than imaging methods such as
X-rays, ultrasound, and radar. For example, T-rays have been
demonstrated to effectively image skin burn severity, tooth
cavities, and skin and breast cancer.
As an alternative method of mammography, for example, T-rays
can detect breast cancer and “see” underground toxins better
than other technologies, such as X-rays. T-rays could also
greatly enhance the mapping of DNA and RNA.
“Our idea is to fully automate analysis of these images,” says
Zhang. “One day it could lead to diagnostic tools based on the
In combination with the chirped probe, the technique offers
highly detailed biological images (even if a patient moves
during the procedure). The images can be layered and mapped in
color to produce high-resolution images for biomedical
A picture of a skin cancer tumor, for example, would be pieced
together using multiple T-ray images at different angles. This
method creates a biologically accurate 3-D picture that gives a
researcher or diagnostician a better understanding of the
disease and how far it has spread.
Important industrial applications are foreseen in the package
inspection and manufacturing quality control. Zhang has
received more than $7 million in grants from the National
Science Foundation, Army Research Office, and Department of
Contact: Megan Galbraith
Phone: (518) 276-6531