Comparison of Two Modes of Photodynamic Therapy for the Treatment of Actinic Keratosis on the Upper Extremities

Inclusion Criteria:

* Male or females ages 35-85
* Fitzpatrick skin type I through IV
* Participants with 4 to 17 clinically confirmed AK lesions of mild to moderate intensity according to Olsen grading in each of two comparable treatment fields on both hands or arms of the patients. The location and maximal size of the treatment fields should be such that PDT is possible with one illumination with BF-RhodoLED® and Blu-U® in parallel. The number of lesions on the two sides of a patient will not be allowed to differ by more than 50%
* Must be willing to give and sign a HIPPA form, photo consent and informed consent form °. Must be willing to comply with study dosing and complete the entire course of the study 6° Female patients will be either of non-childbearing potential defined as: A. Having no uterus B. No menses for at least 12 months with absence of other underlying cause C. (WOCBP) women of childbearing potential must agree to use an effective method of birth control during the course of the study, such as: Oral contraceptive pill, injection, implant, patch, vaginal ring, intrauterine device, Intrauterine coil, Bilateral tubal ligation, Barrier method used with an additional form of contraception (e.g., sponge, spermicide or condom), Abstinence (If practicing abstinence must agree to use barrier method described above (d) if becomes sexually active), Vasectomized partner D. Negative urine pregnancy test results Baseline prior to study entry, Day 30, and Day 60

Exclusion Criteria:

* Hypersensitivity to porphyrins.
* Known hypersensitivity to study medication, which includes soybean phosphatidylcholine.
* Diagnosis of porphyria or photodermatoses.
* Use of photosensitizing medications such as St. John's wort, griseofulvin, thiazide diuretics, sulfonylureas, phenothiazines, sulphonamides, quinolones, and tetracyclines within 1 month of study initiation.
* Presence of wound, suspected BCC or SCC, scar or tattoo, or co-existing potentially confounding skin condition within treatment area.
* Previous PDT in the treatment area within the past 6 months.
* Use of oral/topical retinoids within the treatment area within 1 month of baseline.
* Subjects with recently excessive exposure of the treatment area to sunlight or artificial UV light (e.g.: use of tanning beds/booths and/or sunbathing) or expectations of tanning during the time of the study.
* Female subjects who are pregnant, nursing an infant or planning a pregnancy during the study throughout the course of the study.
* Presence or evidence of any conditions that in the opinion of the investigator might impede the subject's ability to give consent or comply with protocol requirements.
* Ablative laser resurfacing to on their upper extremities within 12 months.
* Non-ablative laser or light procedures to their upper extremities within the past 3 months.
* Microdermabrasion (light or medium skin peel) treatment on their upper extremities within the past 30 days.
* Subjects who have participated in another clinical trial within the past 30 days.
* Presence of any physical conditions which, in the opinion of the investigator, may create an additional risk to subject safety or compromise their ability to comply with the study protocol.
* Presence of any psychological conditions or use of medications which may compromise a subject's ability to comply with the study protocol or provide informed consent
* History of non-compliance with previous clinical trial protocols.