The MultiLite emits only the light spectrum of natural sunlight that is relevant for PDT. A high dose of light is applied, corresponding to two hours of exposure to equatorial sunlight. In our latitudes, it is difficult to obtain comparable doses with natural light.
Another advantage over exposure to natural sunlight is the modulation of penetration depth. The treatment starts with blue light (415 nm, low penetration depth), followed by yellow light (585 nm, medium penetration depth) and finally red light (635 nm, high penetration depth). This results to a layer-by-layer activation of the accumulated PpIX.
When using LEDs for the daylight PDT lamp, it is essential to use light of the wavelength 415 nm (see graphic on the right). The white-light LEDs used for room illumination are not suitable because, due to their technology, they only start to emit light at a wavelength of approximately 450 nm.