Long-term follow-up of a randomized, double-blind, phase III, multi-centre study to evaluate the safety and efficacy of field-directed photodynamic therapy (PDT) of mild to moderate actinic keratosis using BF-200 ALA versus placebo and the BF-RhodoLED® lamp. (Journal of the European Academy of Dermatology and Venereology : JEADV, 2025)