Use of Localized NB-UVB (Levia®) in the Treatment of Plaque-psoriasis

Inclusion Criteria: * Adults 18 years or older with bilateral psoriasis plaques, in general good health as determined by the Principal Investigator by medical history and physical exam. * Able to understand consent procedure * Able to comply with protocol activities * Must have baseline symmetric target lesions with baseline Target Lesion Score (TLS) of 6 or higher (scale of 0-12), i.e., moderate in intensity for each target. Target Lesion Scoring: Thickness, scaling and erythema of the plaques are rated each on a scale of 0-4. The three scores are summed. The minimum score is 0; the maximum is 12. Scores of 6 or greater are considered moderate to severe. Exclusion Criteria: * Patients less than 18 years old * Patients not able to understand consent procedure * Patients unable to comply with protocol activities * Non-English speakers: the study assessments/questionnaires/evaluations are not scientifically validated in languages other than English * Baseline target lesions scores of less than 6 * Patients with a photosensitive disorder or on a medication which has been demonstrated in these patients to cause photosensitivity * Patients receiving concomitant phototherapy to test sites * Patient receiving topical medication to test sites within 2 weeks of study initiation * Patient receiving Methotrexate, Acitretin, Cyclosporine, or other oral medications for psoriasis within 4 weeks of study initiation * Patients receiving Etanercept (Enbrel®) within the past 2 months of study initiation * Patients receiving Infliximab (Remicade®), Ustekinumab (Stelara®), Golimumab (Simponi®) Adalimumab (Humira®) or Alefacept (Amevive®) within the past 3 months prior to study initiation * Receipt of an investigation agent within the past 4 weeks (or within 5 half lives) prior to study ignition * Systemic corticosteroid therapy within the past month * Concurrent use of prohibited medications