, according to three studies of the millimeter-scale near-field communication (mm-NFC) devices.
“These studies highlight the differences between mm-NFC dosimeters and commercial devices in real-world, practical scenarios,” wrote lead authorof the department of biomedical engineering at the Center for Bio-Integrated Electronics at Northwestern University, Chicago, and her coauthors. “The former operate in continuous, uninterrupted modes, whereas the latter capture instantaneous values of intensity at preprogrammed intervals,”they noted. The study was published in Science Translational Medicine.
Separate studies to assess the performance of these “flexible” dosimeters took place in Rio de Janeiro, Brazil, and St. Petersburg, Fla. The Florida study included 13 healthy participants who wore skin-mounted mm-NFC ultraviolet A (UVA) dosimeters on the right back hand, left back hand, left inner arm, and left outer arm, plus a commercial dosimeter on the right wrist. The volunteers walked a 6.44-km path three times: a morning and subsequent afternoon stroll, plus an evening walk 4 days later. Four devices failed during the afternoon exercise, but otherwise, participants received data on their smartphones via the dosimeters at 30-minute intervals.
The Brazilian study was made up of nine healthy participants who wore mm-NFC UVA dosimeters on the thumbnail or the middle fingernail; commercial dosimeters were worn on the wrist of the ipsilateral side. These volunteers engaged in rooftop recreational activities that corresponded to solar zenith angles, along with showering and swimming with the use of soap and skin creams. All sensors remained functional over the 4 days of testing, and 14 of 20 devices remained adhered to the fingernail. Accumulated doses ranged widely, “as expected on the basis of the differences in behaviors,” the authors wrote. These observations imply highly variable UV-associated risks between participants, due not only to differences in Fitzpatrick skin types but also to individual behavior patterns,” they added.
The third study of mm-NFC blue light dosimeters comprised three newborns in an Urbana, Ill., neonatal ICU undergoing blue light phototherapy treatments. Nurses mounted dosimeters on the patients’ chests before phototherapy; an antenna underneath the incubator mattress transmitted continuous wireless measurements of blue intensity and dosage at 20-minute intervals for 20 hours.
The authors acknowledged that these devices and their designs have limitations, including a small detection area as compared to the surface area of a human body. The study’s results “represent localized measurements of exposure, whereas the sun irradiance profile across the body surface is not uniform and varies by position of the sun in the sky over the course of a day.” They recommended that future research could “create anatomic specific risk assessment of UV exposure” via multinodal sensing with UVA/UVB dosimeters on several parts of the body.
The Brazilian UV study was sponsored by La Roche Posay and L’Oreal California Research Center. Research was supported by the National Cancer Institute. Five of the authors reported commercial interests in the technology. Another author reported paid consultation for Aclaris Therapeutics.
SOURCE: Heo SY et al. Sci. Transl. Med. 2018 Dec 5. doi: 10.1126/scitranslmed.aau1643.