The distribution of radiant power in a phototherapy unit equipped with a metal halide lamp.

The effective radiant power of a metal halide lamp for phototherapy of neonatal jaundice was measured in an incubator. This new lamp is characterised by an extremely heterogeneous field of irradiance with a high intensity in the centre and a marked decrease towards the sides. The mean radiant intensity in a central area (20 X 40 cm) of the incubator can be compared with the values achieved with standard fluorescent lamps in an incubator lined with white cloth. As the field of irradiance is more homogeneous in the latter case, advances in therapy are not to be expected from the use of metal halide lamps in their present form.