05 May 2016
New ultrasound sensors developed for improved breast cancer screening
The first prototype ultrasound sensors for a new
improved breast screening technique have been developed as part of
a collaboration between the National Physical Laboratory (NPL),
University Hospitals Bristol (UH Bristol), North Bristol NHS Trust
(NBT), Precision Acoustics Limited and Designworks The team is now
looking for commercial partners to translate the novel development
into a clinical device.
NHS breast cancer screening in England is
currently conducted using X-ray mammography, and further
investigations may involve a clinical examination, more X-ray
mammograms and conventional ultrasound.
During mammography, each breast is compressed
between the two plates of an X-ray machine, which some women find
very uncomfortable, and two X-rays are taken at different angles.
However, the inability of 2D X-ray mammography to separate
overlying tissue can lead to false positives and false negatives,
and the hazards associated with ionising radiation limit the
frequency with which X-rays can be performed. Conventional
ultrasound is highly operator-dependent and suffers from imaging
problems, making cancerous tissue difficult to distinguish from
NPL, UH Bristol, NBT, Precision Acoustics and
Designworks are developing a prototype clinical system for a new
breast screening technique - using ultrasound computed tomography
(UCT) - that may overcome the problems of diagnosing breast disease
using conventional X-ray mammography and ultrasound scans. The new
ultrasound method will be safer and lower cost than currently-used
screening techniques, and the results should be easier for
clinicians to interpret.
NPL has developed and patented a novel detection
method employing pyroelectric sensors, which convert ultrasonic
energy into heat, generating electrical signals which are
eventually used to form the ultrasound image. These large-area
thermal sensors should generate far fewer image artefacts than
conventional piezoelectric detectors, which are sensitive to the
phase of the arriving ultrasound waves.
In the new procedure, the patient's breast will
be placed in a warm water bath between an ultrasound transmitter
and receiver. Ultrasonic waves are sent through the breast and the
amount of energy emerging is measured using the prototype
ultrasound sensor. The ultrasound transmitter array and the
receiver are rotated around the breast, and the resulting
measurements are combined to produce a 3D image of breast tissue
properties. Different tissue types, including those that are
cancerous, can then be identified from this image.
The first prototype pyroelectric sensors have
been manufactured by Precision Acoustics and are currently being
tested and optimised at NPL. Next, the team will develop a platform
combining all the project components into a breast screening system
ready for clinical evaluation. The system will then
be deployed at the Bristol Breast Care Centre
Service (NBT) for clinical evaluation on a small number of
patients, providing the potential for an accurate, safe and
comfortable method of screening for breast cancer.
Dr Margaret Saunders, Dr Sian Curtis, and Dr
Claire Doody, from the Bristol Initiative for Research of Child
Health (BIRCH) Medical Physics & Bioengineering team at UH
Bristol are delighted to be collaborating with clinical colleagues
at Bristol Breast Care Centre, industry partners and the National
Physical Laboratory on this project to design and evaluate new
innovative ultrasound technology.
Dr Saunders said: "My colleagues, Dr Curtis and Dr Doody, and I
think this project is a great example of how, through collaboration
with industry, we can translate the science of medical physics into
leading edge technology to apply in the clinic for the benefit of
breast cancer patients."
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