a-stable-phantom-material-for-optical-and-acoustic-imaging

A Stable Phantom Material for Optical and Acoustic Imaging

Establishing tissue-mimicking biophotonic phantom materials that provide long-term stability are imperative to enable the comparison of biomedical imaging ...

University of Dundee

Optoacoustic tomography (OT) enables non-invasive deep tissue imaging of optical contrast at high spatio-temporal resolution. The applications of OT in cancer imaging often rely on the use of molecular imaging contrast agents based on near-infrared (NIR) dyes to enhance contrast at the tumor site. While these agents afford excellent biocompatibility and minimal toxicity, they present limited optoacoustic signal generation capability and rapid renal clearance, which can impede their tumor imaging efficacy. In this work, a synthetic strategy to overcome these limitations utilizing biodegradable DNA-based nanocarrier (DNA-NC) platforms is introduced. DNA-NCs enable the incorporation of NIR dyes (in this case, IRDye 800CW) at precise positions to enable fluorescence quenching and maximize optoacoustic signal generation. Furthermore, these DNA-NCs show a prolonged blood circulation compared to the native fluorophores, facilitating tumor accumulation by the enhanced permeability and retention (EPR) effect. In vivo imaging of tumor xenografts in mice following intravenous administration of DNA-NCs reveals enhanced OT signals at 24 h when compared to free fluorophores, indicating promise for this method to enhance the optoacoustic signal generation capability and tumor uptake of clinically relevant NIR dyes.

DNA-Based Nanocarriers to Enhance the Optoacoustic Contrast of Tumors In Vivo.

Ductal carcinoma in situ (DCIS) is a non-invasive form of early breast cancer, with a poorly understood natural history of invasive transformation. Necrosis is a well-recognized adverse prognostic feature of DCIS, and non-invasive detection of its presence and spatial extent could provide information not obtainable by biopsy. We describe here imaging of the distribution and extent of comedo-type necrosis in a model of human DCIS using C2Am, an imaging agent that binds to the phosphatidylserine exposed by necrotic cells.

Multi-modal imaging of high-risk ductal carcinoma in situ of the breast using C2Am: a targeted cell death imaging agent.

Correction to: Multi-modal imaging of high-risk ductal carcinoma in situ of the breast using C2Am: a targeted cell death imaging agent.

Recent advances in high power, pulsed, light emitting diodes (LEDs) have shown potential as fast, robust and relatively inexpensive excitation sources for photoacoustic imaging (PAI), yet systematic characterization of performance for biomedical imaging is still lacking. We report here technical and biological validation studies of a commercial dual-wavelength LED-based PAI and ultrasound system. Phantoms and small animals were used to assess temporal precision. In phantom studies, we found high temporal stability of the LED-based PAI system, with no significant drift in performance observed during 6 h of operation or over 30 days of repeated measurements.  dual-wavelength imaging was able to map the dynamics of changes in blood oxygenation during oxygen-enhanced imaging and reveal the kinetics of indocyanine green contrast agent inflow after intravenous administration (T∼6 min). Taken together, these studies indicate that LED-based excitation could be promising for future application in functional and molecular PAI.

Technical validation studies of a dual-wavelength LED-based photoacoustic and ultrasound imaging system.

Early detection and resection of adenomatous polyps prevents their progression to colorectal cancer (CRC), significantly improving patient outcomes. Polyps are typically identified and removed during white-light colonoscopy. Unfortunately, the rate of interval cancers that arise between CRC screening events remains high, linked to poor visualization of polyps during screening and incomplete polyp removal. Here, we sought to evaluate the potential of a hyperspectral endoscope (HySE) to enhance polyp discrimination for detection and resection. We designed, built and tested a new compact HySE in a proof-of-concept clinical study. We successfully collected spectra from three tissue types in seven patients undergoing routine colonoscopy screening. The acquired spectral data from normal tissue and polyps, both pre- and post- resection, were subjected to quantitative analysis using spectral angle mapping and machine learning, which discriminated the data by tissue type, meriting further investigation of HySE as a clinical tool.

James Joseph

School of Science and Engineering,
Centre for Medical Engineering and Technology

University of Dundee

A Stable Phantom Material for Optical and Acoustic Imaging

James Joseph

School of Science and Engineering,Centre for Medical Engineering and Technology

University of Dundee

A Stable Phantom Material for Optical and Acoustic Imaging

School of Science and Engineering,
Centre for Medical Engineering and Technology