fNIR imaging is a spectroscopic method for measuring the level of neuronal activity in the brain. The method is based on neuro-vascular coupling, that is, the relationship between metabolic activity and oxygen level (oxygenated hemoglobin) in feeding blood vessels.

There are three types of fNIR:

• CW - continuous wave - In this method, infrared light shines at the same intensity level during the measurement period. The detected signal is lower intensity static signal (dc-valued)

• FD - frequency domain - In this method, the input signal is a modulated sinusoid at some frequency and the detected output signal has changes in amplitude and phase that correspond to brain activity.

• TR - time-resolved - In time-resolved spectroscopy, a very short IR pulse is introduced, with a pulse length usually on the order of picoseconds. The detected signal is usually a longer signal and has a decay time.

fNIR was first invented by Dr. Britton Chance

Britton Chance

Britton Chance was the Eldridge Reeves Johnson University Professor Emeritus of Biochemistry and Biophysics, as well as Professor Emeritus of Physical Chemistry and Radiological Physics at the University of Pennsylvania School of Medicine.At the 1952 Summer Olympics, Chance won a gold medal in...

 of the University of Pennsylvania

University of Pennsylvania

The University of Pennsylvania is a private, Ivy League university located in Philadelphia, Pennsylvania, United States. Penn is the fourth-oldest institution of higher education in the United States,Penn is the fourth-oldest using the founding dates claimed by each institution...

. Current cwFNIR devices have improved with the advent of electronics.http://www.redorbit.com/news/health/107194/athome_breast_cancer_detector_tested/index.html At the Optical Brain Imaging Lab of Drexel University

Drexel University

Drexel University is a private research university with the main campus located in Philadelphia, Pennsylvania, USA. It was founded in 1891 by Anthony J. Drexel, a noted financier and philanthropist. Drexel offers 70 full-time undergraduate programs and accelerated degrees...

, in collaboration with the University of Pennsylvania, battery-operated, wireless cwfNIR devices have been developed.http://www.newswise.com/articles/view/518934/

External links

• Lab of BC at University of Pennsylvania
• Optical Brain Imaging Lab at Drexel University