Scientists have successfully completed an initial trial of a new, potentially more reliable, technique for screening breast cancer using ultrasound. The team at the National Physical Laboratory (NPL), the UK's National Measurement Institute, working with the University Hospitals Bristol NHS Foundation Trust, are now looking to develop the technique into a clinical device.
Annually, 46,000 women are diagnosed with breast cancer in the UK, using state-of-the-art breast screening methods, based on X-ray mammography. Only about 30% of suspicious lesions turn out to be malignant. Each lesion must be confirmed by invasive biopsies, estimated to cost the NHS 35 million per year. Ionising radiation also has the potential to cause cancer, which limits the use of X-rays to single screenings of at risk groups, such as women over 50 through the National Breast Screening Programme.
There is a compelling need to develop improved, ideally non-ionising, methods of detecting breast lesions and solid masses. Improved diagnosis would reduce unnecessary biopsies and consequent patient trauma from being wrongly diagnosed.
Ultrasound ticks many of the boxes: it is safe, low cost, and already extensively used in trusted applications such as foetal scanning. However the quality of the images is not yet good enough for reliable diagnoses.
Part of the problem lies with the current detectors used. Different biological tissues have different sound speeds, and this affects the time taken for sound waves to arrive at the detector. This can distort the arriving waves, in extreme cases causing cancellation them to cancel each other out. This results in imaging errors, such as suggesting abnormal inclusions where there may be none.
The new method works by detecting the intensity of ultrasonic waves. Intensity is converted to heat that is then sensed by a thin membrane of pyroelectric film, which generates a voltage output dependant on the temperat
|Contact: David Lewis|
National Physical Laboratory