Scoot.
no as far as I am aware, Sunbeds emit UVA and at the wrong frequency to be effective even with the use of a agent.
The two type of phototherapy available are UVB, and UVA. the UVA used for treatment needs an agent to be used called Psoralen, this is where the treatment PUVA comes from (Psoralen + UVA).
Natural sunlight contains UV light across the spectrums of UVA & UVB and for most is beneficial in the treatment of p.
However......... I do use a sunbed for tanning as there is a feel-good factor about being tanned, whether this contributes to less p through feeling good is subjective.
Hope this helps
Roger