Technology

Introducing the MARIA imaging system

Breast tumours may be distinguished from normal breast tissue by their dielectric value. This has led to various attempts to exploit this property for imaging. These attempts include early work at Bristol dating back to 1992.

In recent years, a novel breast imaging technique has been developed based upon a synthetically-focussed but real-aperture multistatic radar and is known as MARIA (Multistatic Array processing for Radiowave Image Acquisition).

An ultra wideband pulse is synthesized using a Vector Network Analyser that sweeps in frequency from 4GHz to 10GHz. The signal is transmitted from each element in a multiple antenna array and then received by all the other elements. The large aperture and wide bandwidth theoretically allow collection of reflected and scattered signals from objects as small as 1.7mm.

The transmitted radiowave signal has a peak power of less than 1mW, the public limits for exposure to radiowaves are not even approached and hence the technology is intrinsically safe and is freely-repeatable.

The technique was initially validated through highly-sophisticated computational models before moving on to experimental validation in complex breast phantoms (models of the breast using simulated tissues with literature dielectric values for skin, fat, and tumour).

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Micrima data

Clinical trials

MARIA is now undergoing extensive clinical testing in humans. Clinical data collected to date is looking very positive for the future of this new imaging modality.

The figure (left) is an animation that shows the focussed data from a post-menopausal woman. This is not simulated, laboratory or phantom data but a MARIA scan from a real cancer patient.

The breast volume is shown as though the patient is standing and facing the observer. The moving plane of data shows a “hot spot” corresponding to the tumour.

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