Some historians believe St. Luke was a physician, and for that reason he is often invoked as a patron saint of doctors and healthcare workers.
However, more importantly he was a spiritual physician, recalling the events of Jesus’ life and providing for us the remedy for our spiritual ills.
Here is a prayer from the 19th century that invokes his intercession for the healing of spiritual disease.
Almighty God, who called St. Luke the Physician, whose praise is in the Gospel to be an Evangelist and Physician of the soul, may it please Thee that by the wholesome medicines of the doctrine delivered by him, all the diseases of our souls may be healed through the merits of Thy Son Jesus, Christ our Lord. Amen.