This PDF file contains the front matter associated with SPIE Proceedings Volume 10415, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

To extend sensitivity field for effective optoacoustic imaging, a novel concept of a non-mechanical point spread function (PSF) adjustment is proposed. Method was validated on phantoms and showed to be useful for distance-adaptive imaging.

This paper will present ultra-compact low-cost laser diode sources, including its diode driver electronics, that have been developed for integration in a photoacoustic imaging system. These laser sources deliver mJ pulses in the near-infrared range.

Photoacoustic imaging and microsurgery have recently attracted attention for applications in oncology. Here, we present a versatile set-up to trigger vapor microbubbles around plasmonic nanoparticles by a combined light-ultrasound excitation. This system enables the detection and parametrization of bubbles as a function of several variables, such us optical fluence, ultrasound intensity, nanoparticles concentration, thus providing useful directions to the development of new strategies for treatments based on optical cavitation.

We present an optoacoustic microscope, combining structural and functional opticalresolution optoacoustic and ultrasound pulse-echo imaging. The system was applied to image Zebrafish larvae and complex vascular networks in the murine brain and ear.

We present an imaging method that uses the random optical speckle patterns that naturally emerge as light propagates through strongly scattering media as a structured illumination source for photoacoustic imaging. Our approach, termed blind structured illumination photoacoustic microscopy (BSIPAM), was inspired by recent work in fluorescence microscopy where super-resolution imaging was demonstrated using multiple unknown speckle illumination patterns. We extend this concept to the multiple scattering domain using photoacoustics (PA), with the speckle pattern serving to generate ultrasound. The optical speckle pattern that emerges as light propagates through diffuse media provides structured illumination to an object placed behind a scattering wall. The photoacoustic signal produced by such illumination is detected using a focused ultrasound transducer. We demonstrate through both simulation and experiment, that by acquiring multiple photoacoustic images, each produced by a different random and unknown speckle pattern, an image of an absorbing object can be reconstructed with a spatial resolution far exceeding that of the ultrasound transducer. We experimentally and numerically demonstrate a gain in resolution of more than a factor of two by using multiple speckle illuminations. The variations in the photoacoustic signals generated with random speckle patterns are utilized in BSIPAM using a novel reconstruction algorithm. Exploiting joint sparsity, this algorithm is capable of reconstructing the absorbing structure from measured PA signals with a resolution close to the speckle size. Another way to excite random excitation for photoacoustic imaging are small absorbing particles, including contrast agents, which flow through small vessels. For such a set-up, the joint-sparsity is generated by the fact that all the particles move in the same vessels. Structured illumination in that case is not necessary.

We present a bimodal system driven by a supercontinuum source to perform photoacoustic-based spectral selective absorption measurements from 500 nm to 800 nm and structural optical coherence tomography imaging at 1300 nm. An energy of 5 to 40 nJ is achieved on sample within a 50 nm bandwidth in the visible range in the photoacoustic channel. Also, a few mW power is also achieved on the sample in the optical coherence tomography channel.

CCD camera based optical ultrasound detection is a promising alternative approach for high resolution 3D photoacoustic imaging (PAI). To fully exploit its potential and to achieve an image resolution <50 μm, it is necessary to incorporate variations of the speed of sound (SOS) in the image reconstruction algorithm. Hence, in the proposed work the idea and a first implementation are shown how speed of sound imaging can be added to a previously developed camera based PAI setup. The current setup provides SOS-maps with a spatial resolution of 2 mm and an accuracy of the obtained absolute SOS values of about 1%. The proposed dual-modality setup has the potential to provide highly resolved and perfectly co-registered 3D photoacoustic and SOS images.

Photoacoustic tomography with an array of line-shaped detectors is presented as a method to collect data for three-dimensional (3D) images in a short time. Signals measured with the detectors, which are arranged on a half-cylindrical surface, yield a projection image of the initial pressure distribution and a 3D image if the sample is rotated. The steps leading to a 3D reconstruction as well as an image of a chicken embryo are shown

Ablation and photothermal therapy are widely employed medical protocols where the selective destruction of tissue is a necessity as in cancerous tissue removal or vascular and brain abnormalities. Tissue denaturation takes place when the temperature reaches a threshold value while the time of exposure determines the lesion size. Therefore, the spatio-temporal distribution of temperature plays a crucial role in the outcome of these clinical interventions. We demonstrate fast volumetric temperature mapping with optoacoustic tomography based on real-time optoacoustic readings from the treated region. The performance of the method was investigated in tissue-mimicking phantom experiments. The new ability to non-invasively measure temperature volumetrically in an entire treated region with high spatial and temporal resolutions holds potential for improving safety and efficacy of thermal ablation and to advance the general applicability of laser-based therapy.

We report an optical fiber ultrasound transmitter with electrospun MWCNT-polymer composite, generating high-amplitude broadband ultrasound. They produced pressures in the range of conventional intravascular imaging transducers, and can be incorporated into catheters/needles for keyhole surgery

A detector design is presented for scanning photoacoustic macroscopy that is based on several concentric ring-shaped elements made of PVDF. Compared to a spherical ultrasound lens, the array provides a long focal depth due to its dynamic focusing ability. It is shown that with ring elements that are inclined towards the region of interest in the sample, significantly better sensitivity and resolution are achieved compared to a planar array. This is demonstrated in a simulation. Based on the simulation results, an array detector was manufactured and its performance was tested in first phantom experiments.