title: Response to Cooke and Sadhra's letter.
authors.affiliation: Department of Occupational Health, Sheffield Teaching Hospitals NHS FT, Sheffield S5 7AU, UK Centre for Workplace Health, Health & Safety Laboratory, Buxton SK17 9JN, UK jon.poole@hsl.gsi.gov.uk.|Department of Radiology, Sheffield Teaching Hospitals NHS FT, Sheffield S5 7AU, UK jon.poole@hsl.gsi.gov.uk.
authors.forename: C J M
authors.initials: CJ
authors.lastname: Poole
authors.affiliation: Department of Occupational Health, Sheffield Teaching Hospitals NHS FT, Sheffield S5 7AU, UK Centre for Workplace Health, Health & Safety Laboratory, Buxton SK17 9JN, UK.|Department of Radiology, Sheffield Teaching Hospitals NHS FT, Sheffield S5 7AU, UK.
authors.forename: T J
authors.initials: TJ
authors.lastname: Cleveland