A low cost multi-wavelength tomography system based on LED sources

We present a multi-wavelength DC system using Light Emitting Diode (LED) sources of four wavelengths in the near infrared range. These LEDs are commercially available, much cheaper than laser diodes, and have adequate power to probe deeply seated lesions. In our system, 8 groups of LEDs of four wavelengths were deployed on a hand-held probe and 10 PMT detectors were fiber coupled to the probe. A co-registered ultrasound (US) array located in the middle of the probe provided lesion location and morphology, which were used for assisting near infrared imaging reconstruction. Experiments evaluated the performance of the LED based DC system using phantom targets.