Anatomical and metabolic small-animal whole-body imaging using ring-shaped confocal photoacoustic computed tomography

Due to the wide use of animals for human disease studies, small animal whole-body imaging plays an increasingly important role in biomedical research. Currently, none of the existing imaging modalities can provide both anatomical and glucose metabolic information, leading to higher costs of building dual-modality systems. Even with image coregistration, the spatial resolution of the metabolic imaging modality is not improved. We present a ring-shaped confocal photoacoustic computed tomography (RC-PACT) system that can provide both assessments in a single modality. Utilizing the novel design of confocal full-ring light delivery and ultrasound transducer array detection, RC-PACT provides full-view cross-sectional imaging with high spatial resolution. Scanning along the orthogonal direction provides three-dimensional imaging. While the mouse anatomy was imaged with endogenous hemoglobin contrast, the glucose metabolism was imaged with a near-infrared dye-labeled 2-deoxyglucose. Through mouse tumor models, we demonstrate that RC-PACT may be a paradigm shifting imaging method for preclinical research

Ring-shaped confocal photoacoustic computed tomography for small-animal whole-body imaging

We report herein a novel three-dimensional photoacoustic computed tomography (PACT) system for small-animal whole-body imaging. The PACT system, based on a 512-element full-ring ultrasonic transducer array, was cylindrically focused and capable of forming a two-dimensional image in 1.6 seconds. The pulsed laser could either illuminate directly from the top or be reshaped to illuminate the sample from the side. Top illumination was mainly used for mouse brain and mouse embryo imaging. Side illumination provided in vivo anatomical images of an adult mouse. By translating the mouse along the elevational direction, the system provided serial cross-sectional images

Anatomical and metabolic small-animal whole-body imaging using ring-shaped confocal photoacoustic computed tomography

Due to the wide use of animals for human disease studies, small animal whole-body imaging plays an increasingly important role in biomedical research. Currently, none of the existing imaging modalities can provide both anatomical and glucose metabolic information, leading to higher costs of building dual-modality systems. Even with image coregistration, the spatial resolution of the metabolic imaging modality is not improved. We present a ring-shaped confocal photoacoustic computed tomography (RC-PACT) system that can provide both assessments in a single modality. Utilizing the novel design of confocal full-ring light delivery and ultrasound transducer array detection, RC-PACT provides full-view cross-sectional imaging with high spatial resolution. Scanning along the orthogonal direction provides three-dimensional imaging. While the mouse anatomy was imaged with endogenous hemoglobin contrast, the glucose metabolism was imaged with a near-infrared dye-labeled 2-deoxyglucose. Through mouse tumor models, we demonstrate that RC-PACT may be a paradigm shifting imaging method for preclinical research

Ring-shaped confocal photoacoustic computed tomography for small-animal whole-body imaging

We report herein a novel three-dimensional photoacoustic computed tomography (PACT) system for small-animal whole-body imaging. The PACT system, based on a 512-element full-ring ultrasonic transducer array, was cylindrically focused and capable of forming a two-dimensional image in 1.6 seconds. The pulsed laser could either illuminate directly from the top or be reshaped to illuminate the sample from the side. Top illumination was mainly used for mouse brain and mouse embryo imaging. Side illumination provided in vivo anatomical images of an adult mouse. By translating the mouse along the elevational direction, the system provided serial cross-sectional images

Whole-body ring-shaped confocal photoacoustic computed tomography of small animals in vivo

We report a novel small-animal whole-body imaging system called ring-shaped confocal photoacoustic computed tomography (RC-PACT). RC-PACT is based on a confocal design of free-space ring-shaped light illumination and 512-element full-ring ultrasonic array signal detection. The free-space light illumination maximizes the light delivery efficiency, and the full-ring signal detection ensures a full two-dimensional view aperture for accurate image reconstruction. Using cylindrically focused array elements, RC-PACT can image a thin cross section with 0.10 to 0.25 mm in-plane resolutions and 1.6 s/frame acquisition time. By translating the mouse along the elevational direction, RC-PACT provides a series of cross-sectional images of the brain, liver, kidneys, and bladder

Tumor glucose metabolism imaged in vivo in small animals with whole-body photoacoustic computed tomography

With the increasing use of small animals for human disease studies, small-animal whole-body molecular imaging plays an important role in biomedical research. Currently, none of the existing imaging modalities can provide both anatomical and glucose molecular information, leading to higher costs of building dual-modality systems. Even with image co-registration, the spatial resolution of the molecular imaging modality is not improved. Utilizing a ring-shaped confocal photoacoustic computed tomography system, we demonstrate, for the first time, that both anatomy and glucose uptake can be imaged in a single modality. Anatomy was imaged with the endogenous hemoglobin contrast, and glucose metabolism was imaged with a near-infrared dye-labeled 2-deoxyglucose

Functional photoacoustic microscopy of pH

pH is a tightly regulated indicator of metabolic activity. In mammalian systems, an imbalance of pH regulation may result from or result in serious illness. In this paper, we report photoacoustic microscopy (PAM) of a commercially available pH-sensitive fluorescent dye (SNARF-5F carboxylic acid) in tissue phantoms. We demonstrated that PAM is capable of pH imaging in absolute values at tissue depths of up to 2.0 mm, greater than possible with other forms of optical microscopy

Tumor glucose metabolism imaged in vivo in small animals with whole-body photoacoustic computed tomography

With the increasing use of small animals for human disease studies, small-animal whole-body molecular imaging plays an important role in biomedical research. Currently, none of the existing imaging modalities can provide both anatomical and glucose molecular information, leading to higher costs of building dual-modality systems. Even with image co-registration, the spatial resolution of the molecular imaging modality is not improved. Utilizing a ring-shaped confocal photoacoustic computed tomography system, we demonstrate, for the first time, that both anatomy and glucose uptake can be imaged in a single modality. Anatomy was imaged with the endogenous hemoglobin contrast, and glucose metabolism was imaged with a near-infrared dye-labeled 2-deoxyglucose