phototherapy
The children in the photograph were recieving natural utraviolet treatment from the hot sun, a treatment called heliotherapy.
Heliotherapy can help clear up the skin condition psoriasis.
People with tuberculosis were treated in health resorts that specialized in heliotherapy.
Heliotherapy (sun therapy) was also used to treat rickets, burns, varicose ulcers, osteomyelitis, septic abscesses, anaemia and fractures.

SMART Vocabulary: related words and phrases

Medical treatment: general words
ACLS
advance directive
allopathic
AMA
aspirate
biosurgery
first-aider
irradiation
light therapy
living will
medicalization
medicalize
orthodox medicine
perorally
pharmacotherapy
phlebotomy
phototherapy
polypharmacy
quackery
telemedicine