Efficacy And Safety Of Illumination Dose Reduction In Red Light Photodynamic Therapy For Actinic Keratoses

The goal of this clinical trial is to compare the tolerance and efficacy of conventional photodynamic therapy (PDT) with red light versus PDT with red light at half dose of illumination, as well as the changes produced by both interventions at the biomolecular level in patients with multiple actinic keratosis on the scalp. The main questions it aims to answer are: Does PDT with half-dose illumination protocol maintain clinical and biomolecular efficacy? Does PDT with half-dose illumination protocol improve intervention tolerance? Researchers will compare both treatment protocols using the patient as its own control. Participants scalp will be divided in two halves, one will be treated with PDT at conventional doses and the other with the half-dose illumination protocol, a skin biopsy will be obtained both pre and post-treatment of each of the areas. Variables will be assessed during the 3 visits of the study.