Elsevier

Photoacoustics

Volume 9, March 2018, Pages 10-20
Photoacoustics

Research article
The characterization of an economic and portable LED-based photoacoustic imaging system to facilitate molecular imaging

https://doi.org/10.1016/j.pacs.2017.11.001Get rights and content
Under a Creative Commons license
open access

Highlights

  • We characterized a commercially available LED-based photoacoustic imaging system.

  • The LED beam profile, spatial/temporal resolution, and penetration depth were measured.

  • Indocyanine green and methylene blue were utilized as exogenous contrast agent, and their detection limits were calculated.

  • The capability for in vivo experiments was demonstrated using human mesenchymal stem cells labeled with a near-infrared dye (DiR) in living mice.

Abstract

Photoacoustic imaging (PAI) is a non-invasive, high-resolution hybrid imaging modality that combines optical excitation and ultrasound detection. PAI can image endogenous chromophores (melanin, hemoglobin, etc.) and exogenous contrast agents in different medical applications. However, most current equipment uses sophisticated and complicated OPO lasers with tuning and stability features inconsistent with broad clinical deployment. As the number of applications of PAI in medicine increases, there is an urgent need to make the imaging equipment more compact, portable, and affordable. Here, portable light emitting diode – based photoacoustic imaging (PLED-PAI) was introduced and characterized in terms of system specifications, light source characterizations, photoacoustic spatial/temporal resolution, and penetration. The system uses two LED arrays attached to the sides of a conventional ultrasound transducer. The LED pulse repetition rate is tunable between 1 K Hz, 2 K Hz, 3 K Hz, and 4 K Hz. The axial resolution was 0.268 mm, and the lateral resolution was between 0.55 and 0.59 mm. The system could detect optical absorber (pencil lead) at a depth of 3.2 cm and the detection limits of indocyanine green (ICG) and methylene blue (MB) were 9 μM and 0.78 mM. In vivo imaging of labeled human mesenchymal stem cells was achieved to confirm compatibility with small animal imaging. The characterization we report here may have value to other groups evaluating commercially available photoacoustic imaging equipment.

Keywords

Portable photoacoustic imaging
LED
Optoacoustic imaging
Molecular imaging

Cited by (0)

Ali Hariri is a PhD student in the Nanoengineering Department at UCSD. He got his M.S. degree and B.S degree in Biomedical Engineering from Sharif University of Technology and Amirkabir University of Technology in Iran. He worked on developing different configurations of photoacoustic imaging technique including computed tomography and microscopy (both acoustic and optical resolution). He also worked on measuring the functional connectivity in resting state using fMRI images on methamphetamine dependence.

Jeanne Lemaster is a Masters/PhD student in the Nanoengineering department at UC San Diego. She received her bachelor’s degree in Chemical Engineering from The Ohio State University in Columbus, Ohio. With over 6 years of experience in research, industry, and engineering consulting, Jeanne has worked for the Department of Defense as well as the private sector on novel imaging techniques, product development, industrial design, and regulatory compliance. She is currently studying the application of nanotechnology on biosystems.

Junxin Wang is a PhD student in the Nanoengineering department at UC San Diego. He got his M.S. degree in Electro-optics from the University of Dayton and a B.S. degree in Optical Information Science and Technology from Changchun University of Science and Technology. He is currently working on biomolecular imaging using nanoparticles and extracellular vesicles.

AnanthaKrishnan Soundaram Jeevarathinam is now a Postdoctoral researcher with Dr. Jokerst Bioimaging Lab in the Nanoengineering department at the University of California, San Diego. His current research is focused on design, synthesis and study of functional organic molecular materials for bioimaging applications. Ananth received his Ph.D. from the council of scientific and industrial research − central leather research institute (CSIR-CLRI), Chennai, India.H e recently completed his postdoctoral studies with Dr. Hemali Rathnayake in the Department of Chemistry at Western Kentucky University.

Daniel L. Chao M.D., Ph.D., is an Assistant Professor of Ophthalmology at the Shiley Eye Institute. Dr. Chao earned a BS in Biomedical Engineering at Virginia Commonwealth University and an M.D. and Ph.D. in Neurosciences at Stanford University. Dr. Chao’s clinical focus is in the medical and surgical treatment of retinal diseases with a special interest in macular degeneration and diabetic retinopathy. He has participated and is an active investigator in many clinical trials. He is involved in multiple interdisciplinary collaborations to develop novel imaging modalities and therapeutic approaches for retinal diseases.

Jesse Jokerst completed a B.S. cum laude at Truman State University. After a Ph.D. in Chemistry at UT Austin with John McDevitt, he completed a postdoc with Sam Gambhir in Stanford Radiology. Now an Assistant Professor in the Department of Nanoengineering at UC San Diego, the Jokerst group is eager to collaborate on projects broadly related to human health and nanotechnology.