Entries by Katy

Polyacrylamide hydrogel phantoms for performance evaluation of multispectral photoacoustic imaging systems

As photoacoustic imaging (PAI) begins to mature and undergo clinical translation, there is a need for well-validated, standardized performance test methods to support device development, quality control, and regulatory evaluation. Despite recent progress, current PAI phantoms may not adequately replicate tissue light and sound transport over the full range of optical wavelengths and acoustic frequencies employed by […]

Spatially distributed sensor array calibration for photoacoustic imaging

To eliminate the limited angle effect of photoacoustic imaging based on ultrasound linear array, spatially distributed ultrasound sensor array is applied. The accurate sensor array position determines the quality of the imaging results. We proposed two methods based on photoacoustic and ultrasound signals to enhance the imaging quality using a full-ring array. Photoacoustic signals are […]

A photoacoustic image reconstruction method for point source recovery

In this paper, a novel Delay and Glow (DAG), back projection-based photoacoustic reconstruction, for point source recovery is presented. The projections of the absorber coefficients are delayed and weighed based on the transducer directivity sensitivity and matched with the other projections from other transducer elements leading to glow the point source at the exact location. […]

Photoacoustic differentiation of cortical from cancellous bone in the lumbar vertebrae of an intact human cadaver to prevent bone breaches during spinal fusion surgeries

In spinal fusion surgeries, it is critical to maintain correct trajectories during the process of creating pedicle holes for screw insertion, in order to avoid accidental bone breaches and screw misplacement, which are characterized by screws placed within surrounding cortical bone rather than the cancellous core of the pedicle. One key difference between these two […]

Parking sensor-inspired approach to photoacoustic-guided hysterectomy demonstrated with human cadavers

Similar to the parking-assist sensors on modern automobiles, which alert drivers of impending impact to an object, we are developing an auditory photoacoustic-based guidance system to assist with avoidance of impending injuries to ureters during hysterectomy procedures. The contribution described in this paper considers international standards for medical alarms. The system was demonstrated during both […]

Generalized contrast-to-noise ratio as a metric of photoacoustic image quality

Multiple image quality metrics are currently available to assess target detectability in photoacoustic images. Common metrics include contrast, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR). The generalized contrast-to-noise ratio (gCNR) is a relatively new image quality metric to assess the probability of photoacoustic target detectability. This paper demonstrates the applicability of gCNR to assess photoacoustic […]

Photoacoustic imaging of fear conditioning neuronal ensembles using a Fos-LacZ gene reporter system in the rat brain in vivo after intrathecal X-gal injection

Current functional imaging techniques, such as functional magnetic resonance imaging, rely upon activity-induced blood flood changes to neurons. This indirect measurement of neuronal activity inherently limits image resolution and specificity, however, advances in transgenic technology and Photoacoustic (PA) methodology have offered new solutions. We previously demonstrated using PA imaging in conjunction with a Fos-LacZ rat […]

Distinction of true or fake blood based on photoacoustic spectroscopy combined with artificial intelligence algorithms

In order to accurately and non-destructively identify the true or fake of blood, the photoacoustic spectroscopy technique was used in this paper. Meanwhile, a kind of custom-built photoacoustic spectroscopy detection system was established. In this system, a 532nm pumped OPO pulsed laser was used as the excitation source, and a focused ultrasonic detector with central […]

Multi-spectral intravascular photoacoustic/ultrasound/optical coherence tomography tri-modality system with a fully-integrated 0.9-mm full field-of-view catheter for plaque vulnerability imaging

Myocardial infarctions are most often caused by the so-called vulnerable plaques, usually featured as non-obstructive lesions with a lipid-rich necrotic core, thin-cap fibroatheroma, and large plaque size. The identification and quantification of these characteristics are the keys to evaluate plaque vulnerability. However, single modality intravascular methods, such as intravascular ultrasound, optical coherence tomography and photoacoustic, […]