BACKGROUND

The prevention of skin cancer in organ transplant recipients (OTRs) through photoprotection is a multifaceted topic. This chapter will discuss ultraviolet radiation, photoprotection, concerns regarding vitamin D, and the educational and behavioral aspects of photoprotection. Skin cancer prevention and photoprotection practices, as outlined in Table 46.1, are essential strategies that may effectively reduce the risk of skin cancer in OTRs.

ULTRAVIOLET RADIATION

The Physics of Ultraviolet radiation

The electromagnetic spectrum spans a wavelength band of radiation with wavelengths ranging from 10−14 m (gamma radiation) to 104 m (radio waves). Ultraviolet radiation (UVR) refers to solar radiation with wavelengths in the 200 to 400 nm range. Radiation in the 400 to 700 nm length is referred to as visible light. In humans, skin is the organ with the highest surface area and is most at risk for damage from UVR exposure. UVR is further subdivided into UVC, UVB, and UVA based on different biological effects. The UVC band (200–290 nm) is known as the “germicidal” band and is almost entirely absorbed by the ozone layer. The UVB band (290–320 nm) is known as the “erythemal” band and is significantly attenuated by the atmosphere. UVA (320–400 nm) is known as “black light” and it is further subdivided into UVA I (340–400 nm) and UVA II (320–340 nm). The shorter wavelengths of UVA II are more erythmogenic than UVA I. Although UVA is more prevalent at the earth's surface, it is less effective than UVB in eliciting erythema in human skin.