Dose quantification in UV phototherapy

Abstract

Ultraviolet light has long been used to alleviate a number of skin conditions, and its efficacy is well known. However, over-exposure to ultraviolet radiation has a number of detrimental effects and thus it is vital to maintain a dose to skin within the therapeutic window. To maximise treatment gain whilst circumventing potential side-effects of over-exposure requires accurate determination of irradiance and skin-dose. This is complicated by the fact that ultraviolet radiation is essentially absorbed at the skin surface, which means that changing orientation of the patient and source can modulate dose received. In addition, irregular patient shapes mean dose must be carefully calibrated. This chapter focuses on methods of determination of dose, clinical protocols for quantifying radiation dose received and mathematical models for estimating these quantities.