Laser device detects breast cancer that X-rays can miss

A new optical screening device could help to detect aggressive breast cancers in younger women which conventional screening sometimes misses, while also being much less umcomfortable for the patient. Developed primarily at Florida International University, the system, which illuminates tissue with a near-infrared diode laser in a hand-held device and uses commercially-available charge-coupled devices (CCDs) as detectors, does not carry the risks of using ionising radiation, unlike X-ray mammography.

Mammography is regarded as the gold-standard for breast cancer detection, but it has a 20 per cent false-negative rate (that is, cancer is present but undetected), this figure rises when it is used on the more dense breast tissue of younger women, in whom breast cancer tends to be more aggressive.

The Florida team developed scanning heads that adapt to the shape of the patient’s breast and use optical fibres to split the laser and direct it at different angles into various points on the breast; the transmitted light is detected by 165 detector fibres linked to the CCD. The device detects the optical absorption of the infrared radiation, which is altered by the presence of haemoglobin; abnormal blood-flow in the breast tissue can indicate the presence of a tumour, which distorts the normal circulatory structure to supply itself with oxygen. Unlike a mammogram, the device allows scanning of the chest wall region.

In a paper in the journal Biomedical Physics and Engineering Express, the team explains that the device detects tumours while the multiple laser source set-up helps to locate them accurately within the tissue. The team has also developed a version of the device which is hand-held and can image both breasts simultaneously, and which can be used in a doctor’s surgery, at the patient’s bedside or even in the home.

“The women scanned always commented on how comfortable it was to be scanned by our device - many of them said that they didn’t feel anything”, claimed researcher Sarah Erickson-Bhatt.

“Eventually, we hope that physicians will be able to use this for real-time imaging of breast tissues as part of regular visits by the patients” added her colleague Anu Godavarty. “We’re current working on the mathematical tools required to process the images and produce 3D tomographic images, in order to determine tumour size and depth.”