Effect of a new narrow-band UVB lamp on photocarcinogenesis in mice

Thirty lightly pigmented hairless (Hr/Hr) mice were irradiated 5 days per week for 30 weeks to assess the photocarcinogenicity of a new Philips TL 01 narrow-band (311 nm +/- 2) UVB lamp. All mice were found to be tumour-bearing after 16 weeks and histologically, 83% of these had definite squamous cell carcinomas. Compared with our previous study where conventional broad-band Philips TL 12 UVB irradiation was used, tumours appeared earlier with the TL 01 lamp. The total irradiation dose was, however, several times greater in the TL 01 assay while the total MED dose was considerably less.