Five years ago, Delphinus announced it had received 510(k) clearance from the FDA and was able to begin marketing its whole breast ultrasound tomography system in the USA. Then 18 months later, just as a British contender with a similar technology announced its intentions, Delphinus received a further $40 million in venture capital funding. A third company called QT Ultrasound – where QT stands for “quantitative transmission” – has just entered the market. However, there’s an interesting twist: the company not only manufactures the QTscan device, but it also owns and operates three new breast imaging centres in California and Michigan.

The QTbreasthealth imaging centres have touted the benefits of the QTscan which does not require compression of the breast which is suspended in a water reservoir (as seen above right) or ionizing radiation, two of the perceived drawbacks of mammography. “For years we’ve seen the growing trend that consumers want to be involved in decisions about their healthcare,” said John Klock, CEO of QT Ultrasound. He continued: “This technology is especially effective for women with dense breasts – about half of all women – who may have gotten false positives with mammography or who have been told they need additional screening.”

A detailed description of the QTscan was published last year in Medical Physics. Seen at left (© American Association of Physicists in Medicine) is the scan head which performs a full 360-degree rotation around the breast before stepping up to the next level. Ultrasound waves are generated by the transmission mode transmitter and enter the breast. Some of the waves pass through the breast and are measured by the transmission mode receiver, while other waves are scattered and measured by the reflection transducers.

The QTscan produces three different images based on: speed of sound; attenuation; and reflection. These three images can then be combined with a statistical classifier to yield a colour-coded image that identifies different tissue types (see below right, © Nature). The company, which received a $15 million grant from the NIH in August 2016, has sought to protect its intellectual property with a United States patent application.

In October 2018, the FDA designated the QTscan as fulfilling an unmet medical need for screening women at high risk for breast cancer. This designation has therefore enabled QT Ultrasound to launch their breast imaging centres. However, under the proposed indications for use, the FDA has mandated: “The QTscan is not to be used as a replacement for standard screening mammography.”