Actinic keratoses (AKs) are the most common premalignant skin tumors. Their effect on appearance and their possible development into squamous cell carcinomas are cause for concern. Photodynamic therapy (PDT) has a reputation for efficacy and for good cosmetic results, particularly in the management of Bowen's disease and thin basal cell carcinomas. PDT has been used to manage AKs, but until recently, comparisons with such established treatments as cryotherapy, …