title: Definition of tissue-air ratio.
authors.affiliation: National Physical Laboratory, Teddington, Middlesex.
authors.forename: J E
authors.initials: JE
authors.lastname: Burns
mesh_terms: D008962:Models, Theoretical; D019047:Phantoms, Imaging; D011874:Radiometry; D011879:Radiotherapy Dosage; D012542:Scattering, Radiation; D009626:Terminology as Topic