Purpose of study: Evaluation of the affect of dose rate on UVR induced skin erythema.

Study design: A single-center, prospective, randomized, crossover, open study.

Number of patients: 20-40

Patient population: Healthy volunteers

Control: Different sites on patients body

Procedure duration: Total 3-5 hours (4 visits)

Duration of follow up: 4 days

Duration of study: Up to 6 months

Primary objectives: To examine the difference in erythemal response as a function of dose rate, and to assess the total amount of energy that is theoretically transmitted through a sunscreen within the range of SPF 2-10.

Inclusion Criteria:

• Fitzpatrick Skin types I-III.
• Age 18-60.
• Absence of obvious sun damage on the volar side of the forearm or other exposure sites.
• Absence of exposure of the arms or other exposure sites to sunlight for two weeks prior to the experiment.

Exclusion Criteria:

• History of skin cancer.
• Multiple nevi or atypical nevi on the forearm.
• Signs of sun damage on the volar side of the forearm or other exposure sites.
• Mentally incompetent.