Development of narrow-band lamps for testing and clinical use.

A compact narrow band lamp for high intensity irradiation has been developed. It consists of a high-pressure mercury lamp, a shutter and water cooled filters for spectral isolation of the light. A mixing device permits simultaneous irradiation with two different wavelenghts by using two lamps. The spectral distribution of the light within the bands is given for seven filter combinations. The construction and calibration of a power meter is also described.

Treatment of psoriasis with trioxsalen baths and dysprosium lamps.

Photochemotherapeutic treatment of psoriasis with trioxsalen baths (0.5 mg/1) for 15 minutes followed by irradiation with dysprosium lamps (Osram HQI-TS) healed or nearly healed the psoriatic lesions in 18 patients within 3-5 weeks. A control area treated with the Ingram method showed a slower healing in 9 of these patients. Methoxsalen bath was not as effective in healing at the concentration used (1 mg/l). The bath method is easy to administer and cosmetically acceptable. Sensitisation to light is maximal immediately after the bath and disappears more quickly than after painting with an alcoholic trioxsalen solution. By using baths, there is less risk of accidental burns or uneven pigmentation than with the often time-consuming local application of psoralen solutions. Toxic systemic effects, which are possible with oral treatment, are less apt to occur. The dysprosium lamps give high intensity in the UV-A region. Exposure times of 10 seconds to 8 minutes are effective in the treatment of psoriasis, where both the UV-B region itself and the UV-A in combination with trioxsalen have psoriasis-healing properties.

Development of high intensity narrow-band lamps and studies of the irradiation effect on human skin. Irradiation with high intensity lamps.

A compact light source has been developed. It consists of a high-pressure mercury lamp, a shutter, and water-cooled filters for selected wavelength regions. A mixing device permits simultaneous irradiation from two lamps of different wavelengths. The spectral distribution of the light for seven filter combinations and the construction of a power meter are also described. The application of the lamps to clinical investigations is illustrated by determination of minimal erythemal and blister doses, as well as pigmentation, for various groups of patients. The light intensities available are high enough to make pain threshold measurements possible in the UV and visible regions.