In recent years, conventional ultrasound (US) imaging devices have been adapted with the photoacoustic (PA) imaging capabilities to simultaneously provide both anatomical and molecular optical contrasts of soft biological tissues. To help optimize the design parameters of such dual modality imaging devices, we present a numerical simulation approach for Bmode beamformed US and multispectral PA imaging using a linear ultrasound transducer array surrounded by a light source. We combined the finite element based simulation platforms for ultrasound and light propagation, K-wave and NIRFast respectively, to model the ultrasound and photoacoustic effects in deep tissue, and created an effective hybrid platform for simulating US and multispectral PA imaging of different configurations. We also developed and applied a spectral unmixing algorithm on multispectral photoacoustic images, obtained from multiple optical wavelengths, to map different molecules (e.g., Indocyanogreen (ICG), Deoxyhemoglobin (Hb), and Oxyhemoglobin (HbO2)) present inside the tissue background. The multi-spectral plots and unmixed spectral images clearly delineated the molecular contrast arising from different regions inside the tissue. The presented simulation platform allows for optimization of key design parameters of both US and PA imaging devices, such as the size of ultrasonic transducer array, and size and the distribution of light sources. Our results demonstrate that the ability to mimic the imaging performance of such dual modality deep tissue-imaging device will help to achieve high molecular sensitivity for the targeted clinical application, thus functioning as a powerful tool for medical device design.
Inadvertent cuts to blood vessels and nerves poses a significant risk during percutaneous needle procedures, often leading to serious injuries and even death. We propose a computer-assisted photoacoustic imaging-based device that is able to detect these vascular structures and robotically guide the surgeons in avoiding them. A fiber-coupled pulsed laser diode capable of generating photoacoustic signals is attached through a ferrule, where a 2.5 mm diameter ultrasound ring transducer receives the corresponding photoacoustic waves. The integrated device is secured on an XYZ axis linear translational stage configuration, and robotically navigated through vessel-modelling phantoms to reach a targeted region of interest. A steering feedback algorithm calculates the relative position of the device with respect to each vessel, generates a 2D map of the navigational plane, and controls the stages to steer the device accordingly towards the target while avoiding the vessels. We first ran the algorithm in a water phantom to demonstrate feasibility, and then in a milk solution to model real tissue scattering. Our proposed device successfully avoids the phantom blood vessels in both cases through photoacoustic detection, and the corresponding 2D navigational path and plane through the phantom is mapped and recorded. Our results demonstrate that a computer-assisted photoacoustic imaging-based device is a viable method of intraoperatively guiding percutaneous needle procedures. The ability of our proposed guidance device to detect and avoid damage to blood vessels and nerves can further be used to optimize biopsies and tumor removal procedures in various parts of the body.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.