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 from MIT]
A sharp drop in white blood cell counts is a major side effect of chemotherapy, leaving patients with the potential of developing a serious infection. The researchers suggest that the device could help prevent thousands of infections that occur annually among chemotherapy patients.
The prototype that the MIT researchers created records a video of blood cells flowing through capillaries in the body, just below the surface of the skin at the base of the fingernail. Then, a computer algorithm analyzes the images to see if the white blood cell levels are dangerously low, according to doctors.
“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 preventative treatment can be deployed,” Carlos Castro-Gonzalez, leader of the research, said in a press release.
During the study, the researchers showed that the device was able to determine if white blood cell counts were too low in 11 patients who were undergoing chemotherapy.
Patients who are going through chemotherapy usually receive a dose every 21 days. Their white blood cell counts typically drop after each does and then gradually increase again. Traditionally, doctors test the white blood cell counts right before the next dose of chemotherapy is given. This means that the doctors don’t know white blood cell counts drop dangerously low.
“In the U.S., one in six chemotherapy patients ends up hospitalized with one for these infections while their white cells are particularly low,” Castro-Gonzalez said.
The researchers report that infections that occur from low white blood cell counts result in long, expensive hospital stays and can even cause death in nearly 7% of cases. Additionally, when a patient has low white blood cell counts, they have to skip their next chemotherapy dose, setting back cancer treatment.
If white blood cell counts fall below the threshold outlined by doctors, the patient can be treated with prophylactic antibiotics and drugs that promote the growth of white blood cells. The researchers suggest that measuring the white blood cell counts between treatments could prevent half of the 110,000 infections that occur each year.
The device features a wide-field microscope that emits blue light and can go 50 to 150 microns below the skin. The light is then reflected back to a video camera. The MIT researchers chose to image the skin below the nail because capillaries are closer to the surface of the skin there. The capillaries there are small enough that white blood cells have to squeeze through one at a time. However, the Technology behind the device does not measure the exact count of white blood cells, but it is able to tell if the patient is above or below the count threshold of 500 neutrophils per microliter of blood.
The researchers tested the device in 11 patients at Massachusetts General Hospital and University Hospital La Paz in Madrid who were undergoing therapy. They collected one minute of video per patient. The device showed 95% accuracy in determining if white blood cells are above and below the threshold.
“Based on the feature-set that our human raters identified, we are now developing an AI and machine-vision algorithm, with preliminary results that indicate the same accuracy as the raters,” said Aurélien Bourquard, the study’s first author.
To help commercialize the device, the researchers are developing an automated prototype. They have also applied for patents on the technology and launched a company called Leuko to commercialize the technology.
“Automating the measurement process is key to making a viable home-use device,” said Ian Butterworth, one of the researchers on the study. “The imaging needs to take place in the right spot on the patient’s finger, and the operation of the device must be straightforward.”
The researchers plant to test the device with other cancer patients with the new automated prototype. They also hope to test the device to get accurate measurements in shorter videos. The researchers plan to further the technology to get more precise blood cell counts to monitor bone marrow transplant recipients or people with infectious diseases.
“This is a balancing act that oncologists must do,” Alvaro Sanchez-Ferro, one of the researchers said. “Normally doctors want to make chemotherapy as intensive as possible but without getting people too immunosuppressed. Current 21-day cycles are based on statistics of what most patients can take, but if you are ready early, then they can potentially bring you back early and that can translate into better survival.”
The research was published in the journal Scientific Reports and was funded by the National Institutes of Health’s Center for Future Technologies in Cancer Care, MIT’s Deshpande Center, the Wallace H. Coulter Foundation at BU, the Madrid-MIT M+Vision Consortium, the EU FP7-PEOPLE-2011-COFUND Program, Fundación Ramón Areces, the MIT Undergraduate Research Opportunities Program (UROP) and the MIT Sandbox Innovation Fund.
The researchers’ prototype device, at right, can image through the skin at the base of the fingernail to generate video of white blood cells flowing through capillaries. [Image from MIT]
