Light-Emitting-Diode-Based Multispectral Photoacoustic Computed Tomography System

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 22; p. 4861
• Main Authors: Agrawal, Sumit, Fadden, Christopher, Dangi, Ajay, Yang, Xinyi, Albahrani, Hussain, Frings, Neilesh, Heidari Zadi, Sara, Kothapalli, Sri-Rajasekhar
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08.11.2019; MDPI
• Subjects: Arrays; Computed tomography; Energy; functional imaging; Hemoglobin; Imaging; Laser arrays; Lasers; Light emitting diodes; light-emitting diodes (led); Low cost; Melanin; Methylene blue; molecular imaging; Oxygen content; Oxygen saturation; photoacoustic computed tomography; Portability; Tunable lasers; Ultrasonic imaging; Validation studies; light-emitting diodes (LED); oxygen saturation; functional imaging; photoacoustic computed tomography; molecular imaging
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19224861

Photoacoustic computed tomography (PACT) has been widely explored for non-ionizing functional and molecular imaging of humans and small animals. In order for light to penetrate deep inside tissue, a bulky and high-cost tunable laser is typically used. Light-emitting diodes (LEDs) have recently emerged as cost-effective and portable alternative illumination sources for photoacoustic imaging. In this study, we have developed a portable, low-cost, five-dimensional ( λ ) PACT system using multi-wavelength LED excitation to enable similar functional and molecular imaging capabilities as standard tunable lasers. Four LED arrays and a linear ultrasound transducer detector array are housed in a hollow cylindrical geometry that rotates 360 degrees to allow multiple projections through the subject of interest placed inside the cylinder. The structural, functional, and molecular imaging capabilities of the LED-PACT system are validated using various tissue-mimicking phantom studies. The axial, lateral, and elevational resolutions of the system at 2.3 cm depth are estimated as 0.12 mm, 0.3 mm, and 2.1 mm, respectively. Spectrally unmixed photoacoustic contrasts from tubes filled with oxy- and deoxy-hemoglobin, indocyanine green, methylene blue, and melanin molecules demonstrate the multispectral molecular imaging capabilities of the system. Human-finger-mimicking phantoms made of a bone and blood tubes show structural and functional oxygen saturation imaging capabilities. Together, these results demonstrate the potential of the proposed LED-based, low-cost, portable PACT system for pre-clinical and clinical applications.