title: Sun protection factor determination in vivo using a single exposure on sunscreen-protected skin.
abstract: BACKGROUND
  Determining sunscreen sun protection factors (SPFs) in a cohort of volunteers, particularly on products designed to provide high levels of protection, can be time-consuming. The conventional approach is to administer to each subject a series of exposures (normally between five and seven) on their sunscreen-protected skin.
  
  
  METHODS
  A method, based on Gaussian statistics, is proposed that requires just a single exposure on the sunscreen-protected skin in volunteers to arrive at a reliable estimate of the mean SPF of a test product.
  
  
  CONCLUSIONS
  The method is shown to yield an estimate of a product's mean SPF that is comparable, or better, in accuracy to estimates obtained by conventional multi-exposure testing.
authors: Regional Medical Physics Department, Newcastle General Hospital, Newcastle upon Tyne NE4 6BE, UK. b.l.diffey@ncl.ac.uk
authors: Brian L
authors: BL
authors: Diffey
mesh_terms: D015331:Cohort Studies; D006801:Humans; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012882:Skin Tests / Q000379:methods*; D013471:Sunburn / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D014466:Ultraviolet Rays
chemical_list: D013473:Sunscreening Agents