Aminolevulinic acid is being used as an alternative to HPD. It does not produce the prolonged photosensitivity that HPD does. It is, however, available only on an experimental basis at this time. Laser Therapy The carbon dioxide laser may be used as a cutting instrument, much like a scalpel. It is useful for removing superficial basal and squamous cell carcinomas in patients with bleeding disorders or who have tumors in locations that tend to be bloody, such as the scalp. The wound remaining after the procedure is similar to that left by a scalpel excision . When a defocused beam is used to remove lesions, the cosmetic result appears similar to the wound made by electrodesiccation and curettage. The most appropriate method of curing a specific skin cancer is the most effective, least toxic, most efficient and most cosmetically elegant therapy, which may be a combination of any of these standard or investigational treatments.