Smartphone-based dual radiometric fluorescence and white-light imager for quantification of protoporphyrin IX in skin.

"Disclosures AJR and BWP are co-inventors of a pending patent related to systems and methods for the quantitative dosimetry of photodynamic therapy in skin (application US17/154,430). The other authors declare no conflicts of interest."

"This work was partially funded by the Norris Cotton Cancer Center Prouty pilot award, the National Institutes of Health (Grant No. P01 CA084203), and the PhD Innovation program at Dartmouth. Support also provided by the Henry Luce Foundation and its Clare Boothe Luce Fellowship (MG). The Ameluz® topical drug used in this study was supplied by Biofrontera, Inc."

"All human imaging was performed on patients who were recruited from the standard patient population appearing with AKs at the Dartmouth-Hitchcock Department of Dermatology Clinic and gave informed consent before enrollment. The study was approved by the Dartmouth-Hitchcock Health Institutional Review Board and registered with ClinicalTrials.gov (NCT03805737). Cleaning of the treatment area (face, forehead, and scalp) using a 70% isopropyl solution was followed by topical application of a 10% ALA gel (Ameluz®, Biofrontera). Following ALA application, patients were incubated under room-light conditions for 30 mins, with the area of treatment uncovered. Following the ALA incubation, light irradiation was performed on the treatment areas. For the study, patients either received 10 min of high irradiance red-lamp treatment or 2 hrs of indoor daylight treatment. Irradiance spectra and PpIX-equivalent dose are provided in the Supplementary Material following the methods described in Ruiz et al. In brief, the effective PpIX dose calculations show that the indoor-daylight treatment provides a higher dose (2×) for depths below <250  μm, which corresponds to the location of the upper blood dermis in a seven-layer skin model. The delivered PpIX-effective dose is equivalent within 20% in the 350 to 1000  μm range, with an equal dose delivered at 700  μm between the two treatment regimens."