A Photodynamic Therapy for Treatment of Actinic Keratoses

Inclusion Criteria: Age greater than or equal to 18 years * Have a t least 4 nonhypertrophic AK lesions on the body * The subjects are in good health * The subject has the willingness and the ability to understand and provide informed consent for the use of their tissue and communicate to the investigator Exclusion Criteria: * Subjects who are pregnant or lactating * Subjects with a history of cutaneous photosensitivity or porphyria, hypersensitivity to porphyrins, or photodermatosis * Subjects with use of photosensitizing drugs within 1 week of study start * Subjects with use of topical medications such as corticosteroids, alpha-hydroxyacids or retinoids 2 weeks before study entry * Subjects with systemic steroid therapy within 4 weeks before study entry * Subjects who received previous treatment of target AKs * Subjects with systemic treatment with chemotherapeutic agents, masoprocol (Actinex), immunotherapy, or retinoids within 2 months of study entry * Subjects with prior history of hypersensitivity reactions to lidocaine * Subjects who are unable to understand the protocol or to give informed consent