Rohde & Schwarz has supplied high speed vector network analyzers to Bristol University spin-out Micrima for the clinical trials of their revolutionary breast cancer screening technique.
MARIA (Multistatic Array processing for Radiowave Image Acquisition) is an ultra wideband radio system that can be used to detect tumours by generating high-resolution 3D images of the human breast. The technique which avoids exposing women to X-ray radiation, is fast and inexpensive. It is also expected to be better at identifying breast cancer in younger women.
Professor Ian Craddock and Professor Alan Preece from Bristol University, England, developed the wideband antenna array, which lies comfortably beneath the breast. The array connects via a switch matrix to the test ports of a R&S ZVT8 Vector Network Analyzer, which takes fast frequency sweep measurements. Post-processing is carried out on a computer using software developed by the research group.
Roy Johnson, Executive Chairman of Micrima, said, "The new 3D breast screening platform under development aims to be safer, more convenient and more economically viable in a greater number of countries, in addition to providing a practical solution to screening women below the age of 50."
Funding from Micrima has enabled the radar-based breast imaging system to undergo further technical development and clinical trials. The first set of clinical trials have just concluded. Conducted at Frenchay Hospitalís Breast Care Centre in Bristol in collaboration with Dr Mike Shere, as well as Southmead Hospital in Bristol, they have been very successful.
Commented Professor Ian Craddock from Electrical & Electronic Engineering at Bristol University: "Current mammography systems play an important role in the detection of breast cancer but suffer from relatively high missed- and false-detection rates, and involve uncomfortable compression of the breast."
He added, "Speed of measurement is critical for this application. We were therefore very impressed by the fast measurement capability offered by the R & S ZVT8 8 Port Network Analyser. The analyserís parallel data acquisition across 16 receivers has enabled us to reduce measurement time from a little over one minute to nine seconds, which is good news for patients and for screening throughput."
"In addition to the R&S ZVTís speed, its ability to emulate other network analyzers has meant that the Bristol team has been able to get up to speed with the new instrument much faster," said Jamie Lunn, Rohde & Schwarz UKís RF & Microwave product specialist. He concluded: "We are immensely proud that our instrumentation is being used to progress such a valuable research goal."
Micrimaís goal is to create a compact, low cost version of the MARIA system that could be situated in GP surgeries and mobile screening units. With breast cancer being the most common cause of death for women aged between 35 and 59 in Europe, it is hoped by all involved that the technique may eventually ensure that all women, regardless of age, could be routinely screened.
The Maria imaging system technology
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.
MARIA is a novel breast imaging technique based upon a synthetically-focussed but real-aperture multistatic radar.
An ultra wideband pulse is synthesized using the vector network analyzer 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).
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.
Micrima MARIA clinical prototype in situ at clinical trial centre
The figure (below) is part of 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.Background
Micrima was spun out, in 2006, from the University of Bristol, in the UK, with the help of Wyvern Seed Fund, Bath Ventures, NESTA and a business angel source.
With growing laboratory and clinical data in support of the technology and its intended use, the company has, in early 2008 and late 2009, raised further finance from Swarraton Partners, South West Ventures and Finance South West Growth Fund.http://www.micrima.com/
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