A Cost-Efficient Multiwavelength LED-Based System for Quantitative Photoacoustic Measurements

Abstract

The unique ability of photoacoustic (PA) sensing to provide optical absorption information of biomolecules deep inside turbid tissues with high sensitivity has recently enabled the development of various novel diagnostic systems for biomedical applications. In many cases, PA setups can be bulky, complex, and costly, as they typically require the integration of expensive Q-switched nanosecond lasers, and also presents limited wavelength availability. This article presents a compact, cost-efficient, multiwavelength PA sensing system for quantitative measurements, by utilizing two high-power LED sources emitting at central wavelengths of 444 and 628 nm, respectively, and a single-element ultrasonic transducer at 3.5 MHz for signal detection. We investigate the performance of LEDs in pulsed mode and explore the dependence of PA responses on absorber’s concentration and applied energy fluence using tissue-mimicking phantoms demonstrating both optical absorption and scattering properties. Finally, we apply the developed system on the spectral unmixing of two absorbers contained at various relative concentrations in the phantoms, to provide accurate estimations with absolute deviations ranging between 0.4 and 12.3%. An upgraded version of the PA system may provide valuable in-vivo multiparametric measurements of important biomarkers, such as hemoglobin oxygenation, melanin concentration, local lipid content, and glucose levels.

Non-Invasive Monitoring of Human Health by Photoacoustic Spectroscopy

“…The time sequence of volunteers’ blood glucose concentration detected by DCW-PAS is consistent with the results of the other three invasive blood glucose measurement tools, which shows the potential of DCW-PAS in detecting blood glucose concentration. Utilizing two high-power LED sources emitting at central wavelengths of 444 and 628 nm, Orfanakis et al developed a compact, economical, and multi-wavelength PA sensing system [ 46 ]. An upgraded version of this system may be used to measure various important biomarkers, such as glucose levels, melanin concentration, and oxyhemoglobin saturation, which shows the great potential of a portable PA system.…”

Observing temporal variation in hemolysis through photoacoustics with a low cost LASER diode based system

“…Some experiments regarding frequency domain photoacoustic microscopy were performed using high power LEDs as the source of illumination 26 , 27 . A recent work on photoacoustic quantification by spectral unmixing technique was also reported to be using high power LEDs 28 . In addition to these, various other photoacoustic systems with low cost optical sources and their applications can be found in the review article by Singh, M. K. A.…”