Preclinical Photoacoustic CT Scanner – Nexus 128

The Nexus 128 from ENDRA is a full 3-Dimensional Photoacoustic Computed Tomography scanner for non-invasive contrast enhanced and molecular imaging applications. It is suited to working with near infra-red absorbing dyes or fluorescent probes. Furthermore, the Nexus 128 is the only commercially available 3-D photoacoustic imaging system on the market.

Key Features

  • Predefined tumor biology and probe uptake protocols
  • Flexible ‘research mode’ for advanced scan parameters
  • Advanced reconstruction algorithms
  • Easy to use graphical user interface
  • Compact, easy-to-site system
  • Powerful viewing and analysis software

Photoacoustic Imaging

Photoacoustic imaging marries the benefits light or optical microscopy and ultrasound technology. This combination produces images that boast high optical contract and high ultrasound resolution at depth. This unique combination makes photoacoustic imaging superior to other imaging modalities when you are looking to generate detailed structural and functional images to gain the best possible understanding of the critical disease system you are investigating.

Photoacoustic imaging is a powerful tool for imaging of anatomy, physiology and labelled molecular targets.


The Nexus 128 is the ideal tool for research in the areas of:

  • Molecular probe uptake and distribution
  • Tumor vasculature – hemoglobin concentration
  • Tumor hypoxia – SO2
  • Tissue perfusion
  • Vascular imaging
  • Pharmacokinetics
  • Spectral imaging

Nexus 128 Applications

Molecular Probe Uptake

The Nexues 128 is a non-invasive imaging system ideally suited to the quantitative investigation of the molecular probe uptake of distribution. Its 3D imaging capability offers superior sensitivity when compared to slice-based scanners.

It acquires dynamic (4-D) photoacoustic CT scans which enable researchers to quantify probe uptake. As each scan is 3-D, it becomes easy to determine spatial variations in probe uptake throughout a given volume.

Fluorescent Probe Imaging

The Nexus 128 is able to image fluorescent tumour probes at multiple wavelengths. The study shown below shows a haemoglobin signal which reveals how the probe diffuses relative to the vasculature.

Endra Nexus 128 photoacoustic computed tomography (CT) scanner data

Probe Uptake in Glioblastoma – 4D Data

The graph has been produced using Endra’s probe Uptake application to analyse 4-D data to assess the uptake of molecular probes. This example looks at the gold nanoparticle uptake of an orthotopic mouse model of glioblastoma. 3-D photoacoustic data was acquired at 15 minute intervals.

The images are of a molecular diagnostic that is specifically targeted at glioblastoma mice brain tumours. The sequence of images shows the uptake of the drug into mouse brain tissue

Endra Nexus 4D probe data and images

Quantifying in vivo Tumour Imaging

Another application that the Nexus 128 is suited to is non-invasive quantification of tumour vasculature in mouse models. In this instance the endogenous contrast of blood can be used to produce tomographic images of the blood vessels within cancerous tumours, in turn providing parametric maps of haemoglobin concentration (CtHb). By tracking these parameters longitudinally, researchers have a quantitative tool for study the response of tumours to various therapies.

Quantifying Anti-Angiogenic Therapy in Mouse Model

Another application that the Nexus 128 is ideally suited to is quantifying the vascular response to anti-angiogenic therapy in MCF-7.

Endra Nexus 128 photoacoustic computed tomography (CT) scanner data

Intra-Tumour Vascular Heterogeneity

Multi-wavelength acquisition and spectral deconvolution

Endra Nexus 128 photoacoustic computed tomography (CT) scanner data

Intra-Tumour haemoglobin concentration and SaO2

Endra Nexus 128 photoacoustic computed tomography (CT) scanner data of a tumour

Scan CapabilitiesSingle wavelength, multi-wavelength, or dynamic scan protocols
LaserWavelength Tuning Range: 680 - 950 nm
Pulse Repetition Rate: 20 Hz
3D DetectorHemispherical array of 128 individual acoustic receiver elements (5 MHz center frequency)
Digital Acquisition System128 channel digital acquisition system samples all 128 transducers every laser pulse without multiplexing
Analysis WorkstationApple iMac with OsiriX
Application specific OsiriX plugins for data quantitation
Scanner Dimensions(91 cm H x 97 cm W x 71 cm D)