Patients undergoing chemotherapy face the risk of their white blood cell count dropping sharply, which leaves them vulnerable to dangerous infections. Such complications account for thousands of infections in chemotherapy patients every year, delay future chemotherapy treatments and can even be fatal. In hopes of catching these drops before they become serious, researchers at MIT have now created a portable device that can be used to monitor patients’ white blood cells at home, without taking blood samples. The device is described in a paper published in Scientific Reports.
The device consists of a wide-field microscope that emits blue light, which can penetrate about 50 to 150 microns below the skin and reflects back to a video camera. The skin is imaged at the base of the nail where the capillaries are located very close to the surface of the skin. The capillaries are so narrow here that white blood cells must squeeze through one at a time, making them easier to see. While the technology does not provide precise white blood cell counts, it can reveal whether the counts are below the threshold for being considered dangerous—500 neutrophils per microliter of blood.
"Our vision is that patients will have this portable device that they can take home, and they can monitor daily how they are reacting to the treatment. If they go below the threshold, then preventive treatment can be deployed," says Carlos Castro-Gonzalez, a postdoc in MIT's Research Laboratory of Electronics (RLE) and the leader of the research team.
The device was tested in 11 patients at Massachusetts General Hospital and University Hospital La Paz in Madrid. Determination of whether a patient’s blood cell levels were above or below the threshold was achieved with 95% accuracy.
In the tests, one minute of video was record per person and an assistant then watched the video, noting whenever a white blood cell passed by. The researchers are in the process of developing a computer algorithm to perform this task automatically, based on the performance of the human observers.
The team has applied for patents on the technology and launched a company called Leuko to commercialize it. The next steps will be in building a prototype with the automation feature built in and eventually to further test and improve the technology to expand its uses.
Image: MIT researchers have developed a way to measure white blood cell levels by imaging the cells as they flow through capillaries at the base of the fingernail. In these images, the white blood cells are marked by crosses. Image courtesy of MIT/The Leuko Project.