Anti-terror system finds cancers
Tom Shelley reports on the adaptation of a technology used to find weapons to identifying breast cancer.
Terahertz imaging, much publicised because it can identify non-metallic threats under the clothes of possible terrorists, can also be used to correctly identify cancerous tissue in the human breast during the course of an operation.
Working in the 1,000 GHz, 0.3mm wavelength band, the technology also has many potential applications in non-destructive examination of composites and integrated circuits.
TeraView chief operating officer Padraig O'Kelly explained that women in the west have a one in eight lifetime risk of contracting breast cancer. In 60% to 70% of cases, it is common practice to remove only cancerous parts of a breast, rather than the whole organ. However, without a quantitative, real-time method of identifying whether all diseased material has been removed during an operation, 20 to 25% of patients – more than 4,000 in the UK in any one year – are called back for an additional operation to remove further material. This is expensive, traumatic for the patient, and may delay patient adjuvant therapy.
The TeraView probe can solve this problem. It uses the same technology as the weapon-detecting system that is in service at US Defence establishments and which is being considered for deployments at UK airports. In the approach, based on work by Professor Michael Pepper and colleagues at Toshiba Labs, a gallium arsenide substrate is struck with a 90fs pulse of near infra red light, resulting in a 500fs pulse of TeraHertz radiation. Power levels are extremely low and there is absolutely no risk to the patient.
In a two-year development and ex vivo test programme part funded by the Technology Strategy Board, it was found that 90% of cancers and 81% of normal tissue, adipose and fibrous, were distinguished correctly. The overall proportion correctly identified was 82%.
A prototype machine is currently undergoing trials at Guy's Hospital in London. This is a system mounted on a trolley, with a probe on an umbilical and a window on the end of the probe. Terahertz radiation is sensitive to water but, while this causes some problems, O'Kelly points out: "It's the water-sensitivity that helps show up the cancer."
The system is not intended to replace biopsies, but to be able to assist the surgeon during the course of an operation – DCIS – Ductal Carcinoma In Situ. The next stage in development is to be multi-centre trials, and then commercialisation. O'Kelly said: "We are now seeking partners with a track record in delivery of scientific instrumentation to help fund the planned multi-centre trials in 2011 and to commercialise the resulting medical device."
Other potential medical applications include the detection of cancerous sentinel lymph nodes, but the technology is additionally suited to identifying impact damage in composites and faults in multi layer integrated circuits. It has also been mooted as a way of detecting low or no metal containing improvised explosive devices.
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