A phototherapy device includes a high intensity light source secured to a leaky light conducting fiber to leak light along the length of the fiber. The light fiber is illuminated at either or both ends by the light source and the light fiber is generally oriented in a 3-D spiral pattern to form a dome of light to provide phototherapy to an area of a patient's scalp to be treated. A generally hemispherical shell is formed of a first or inner translucent diffuser layer secured to a second or outer reflective layer, the first and second layers encapsulating the 3-D non-overlapping spiral pattern light fiber. A control system is also provided to turn off the light source when a break or discontinuity occurs in the fiber.