Researchers at the Massachusetts Institute of Technology (MIT) have developed a 3D-printed patch that can be attached to a bra using magnets. This innovative device is based on the same technology as conventional ultrasound scanners used in hospitals today. The difference is that it is made from a new piezoelectric material, which makes the device much more compact and portable. These materials are widely used as transducers and sensors in medical ultrasound imaging systems. By reacting to external mechanical stress and then separating positive and negative electrical charges, they can convert the mechanical energy of vibrations into electrical energy.
Breast cancer is the most common cancer in women. If diagnosed at an early stage, the survival rate is close to 100%. However, if it is detected later, it drops to 25%. Early detection is therefore vital. The interstices (also known as matrices) in the honeycomb structure of the new patch allow it to contact the skin. The device is inserted into a small tracer that can be moved into different positions to obtain images of the entire breast from different angles. The images produced have a resolution similar to that of conventional ultrasound probes.
Another advantage of the patch is that it does not require any special expertise to use. In contrast, conventional scanners require highly qualified personnel. The device can also be used repeatedly, and could therefore serve as a preventive imaging device for women at high risk of breast cancer. It could also diagnose tumours in women who do not have access to conventional screening.
Detecting elements as small as 0.3 cm in diameter
In collaboration with MIT’s Center for Clinical and Translational Research, the researchers, led by Canan Dagdeviren, tested their device on a 71-year-old woman with a history of breast cysts. They found that their device could detect cysts as small as 0.3 cm in diameter, which is the same size as early-stage tumours. They were also able to image tissue to a depth of eight centimetres – about as deep as you can get with a conventional ultrasound scanner.
« In current ultrasound breast imaging technologies, although handheld ultrasonography (HHUS) and automated breast ultrasound (ABUS) are the preferred methods, there are still technical gaps that need to be overcome for ultrasound to become a reliable option for breast cancer screening, » explains Canan Dagdeviren. « These gaps are: HHUS relies heavily on the expertise and training of technicians to manually scan the whole breast by applying strong compression, which is uncomfortable for the patient; and ABUS can scan the whole breast at once, but skin contact remains poor (due to the use of a liquid medium between the tissue and the stationary machines used in a hospital setting). »
The new device is the first ultrasound technology to fill both these gaps. It offers a non-invasive, wide-field-of-view, real-time and continuous monitoring of curved breast tissue. This could provide doctors with reliable, cost-effective and accessible breast imaging for early detection of breast abnormalities. Canan Dagdeviren adds, « Our work represents a fundamental change in the way clinicians and patients can screen for, detect and diagnose breast cancer, especially as early detection is key to increasing survival rates. »
The bra/patch consists of a tracer that moves over the breasts, following a specific trajectory to allow for a maximum field of vision. By being connected to the “Verasonics” system, the matrix in the patch can send high-frequency pulses to the patch’s piezoelectric components and receive an ‘echo’ from other components. « We then generate images by combining all the pulse-echo signals using a specially designed algorithm, » explains Canan Dagdeviren. « The images of the breast tissue are recorded by the system and the cysts can be observed on a screen.”
Towards miniaturisation
A number of challenges need to be addressed if the portable ultrasound patch is to become a marketable product. Firstly, it will have to be miniaturised even further. This will involve integrating complex ultrasound components, such as transducers and electronics, into a compact, lightweight structure, without compromising image quality. Ideally, the quality of the ultrasound image should be comparable to that obtained with traditional ultrasound scanners.
Early detection is key to increasing survival rates.
A wearable patch also obviously needs to be comfortable for the wearer, and achieving a balance between flexibility, softness and adequate adhesion to ensure proper contact with the breast without creating discomfort remains challenging. « We need to create a user-friendly interface too, » explains Canan Dagdeviren. « This should allow healthcare professionals to monitor and interpret the device’s output. The patch itself need to be designed with ease of use in mind, so that it can be easily integrated into medical workflows.
AI-aided analyses
The researchers also hope to develop a method in which artificial intelligence (AI) can be used to analyse changes in images over time. This would offer more accurate diagnoses than comparing images taken months or even years apart.
Finally, the device will need to be clinically validated, she adds. « Any medical device, including such a wearable ultrasound patch, must undergo rigorous clinical testing and validation to ensure its safety and efficacy in real-world scenarios. This means working closely with medical professionals and patients. »
Developing a portable system for daily self-screening is also a subject of study for the research team. « Such a system will allow for individualised ultrasonographic profile generation along with big data collection (that is, images of tissue and results analysed by AI) to send to doctors for rapid and objective assessments. » It could also be integrated into a wireless communication system to monitor the development of tumours over time or in response to medical therapies.
Isabelle Dumé
Reference : Science Advances
