Phase 3 Study of Levulan With New Blue Light for AK on the Face or Scalp

Inclusion Criteria: * Four to fifteen Grade 1/2 actinic keratosis lesions (AKs) on the face OR balding scalp Exclusion Criteria: * Pregnancy * grade 3 and/or atypical \>1cm AKs within Treatment Area and/or more than 15 AKs of any Grade within the Treatment Area * history of cutaneous photosensitization, porphyria, hypersensitivity to porphyrins or photodermatosis * lesions suspicious for skin cancer (skin cancer not ruled out by biopsy) or untreated skin cancers within the Treatment Area * skin pathology or condition which could interfere with the evaluation of the test product or requires the use of interfering topical or systemic therapy * Subject is immunosuppressed * unsuccessful outcome from previous ALA-PDT therapy * currently enrolled in an investigational drug or device study * has received an investigational drug or been treated with an investigational device within 30 days prior to the initiation of treatment * known sensitivity to one or more of the vehicle components (ethyl alcohol, isopropyl alcohol, laureth 4, polyethylene glycol) * has active herpes simplex infection in the Treatment Area OR a history of 2 or more outbreaks within past 12 months, in the Treatment Area * use of the following topical preparations on the extremity to be treated: * Keratolytics including urea (greater than 5%), alpha hydroxyacids \[e.g.glycolic acid, lactic acid, etc. greater than 5%\], salicylic acid (greater than 2%) within 2 days of initiation of treatment. * Curettage or Cryotherapy within 2 weeks of initiation of treatment * Retinoids, including tazarotene, adapalene, tretinoin, within 4 weeks of initiation of treatment. * Microdermabrasion, laser ablative treatments, ALA-PDT, chemical peels, 5-FU, diclofenac, ingenol mebutate, imiquimod or other topical treatments for AK within 8 weeks of initiation of treatment. * use of systemic retinoid therapy within 6 months of initiation of treatment.