An Ultra-Low-Cost Optoacoustic Method for Imaging Specific Biological Structures

<b>Background/Objectives:</b> Optoacoustic imaging technologies are emerging as promising tools for clinical practice. Several systems have the potential to fill specific niches in the medical imaging landscape thanks to a unique performance based on the combination of rich optical absorption contrast and high ultrasonic penetration-to-resolution ratios. However, current optoacoustic methods rely on tomographic reconstructions, which impose significant complexity on the systems in terms of number and distribution of transducers, acquisition electronics, and general operation. As a result, optoacoustic tomography apparatus are generally expensive and bulky and require intensive training for their operation. Here, we report on an optoacoustic imaging method that uses a single ultrasound transducer and non-tomographic image formation to overcome the drawbacks of classical tomographic methods. The method is designed for retrieving layered slab-like biological structures like tattoo ink, subcutaneous fat, muscles, or cerebrospinal fluid below the fontanelle. Moreover, it can be adapted to other geometries. <b>Methods:</b> We have implemented the method in a user-friendly, compact, simple, and low-cost system and tested its performance using simulations, synthetic phantoms, and biological phantoms containing tattoo ink. <b>Results:</b> Our results indicate that the system can discriminate slab-like structures from other shapes and recover them with the axial resolution of tomographic optoacoustic methods. The findings also suggest that the system has the potential to improve tattoo removal procedures. We further discuss its implications for pediatrics, traumatology, or endocrinology. <b>Conclusions:</b> This work paves the way for a new generation of simple, easy-to-use and low-cost imaging systems with the potential to impact several medical fields.