Measurement of cerebral blood flow and metabolism using high power light-emitting diodes

In this paper, we study key properties of commercially available HPLEDs, with a focus on the study of the brain. Of particular interest here are optical output power and available wavelengths. Furthermore, we demonstrate a lock-in amplification technique suitable for use with HPLEDs in brain studies. Based on the presented measurement technique, we conduct experimental measurements on CBF in the cortex and analyse fluctuations in blood oxygen level at different combinations of wavelengths.