title: Current status of kilovoltage (kV) radiotherapy in the UK: installed equipment, clinical workload, physics quality control and radiation dosimetry.
abstract: OBJECTIVE
  To assess the status and practice of kilovoltage (kV) radiotherapy in the UK.
  
  
  METHODS
  96% of the radiotherapy centres in the UK responded to a comprehensive survey. An analysis of the installed equipment base, patient numbers, clinical treatment sites, quality control (QC) testing and radiation dosimetry processes were undertaken.
  
  
  RESULTS
  73% of UK centres have at least one kV treatment unit, with 58 units installed across the UK. Although 35% of units are over 10 years old, 39% units have been installed in the last 5 years. Approximately 6000 patients are treated with kV units in the UK each year, the most common site (44%) being basal cell carcinoma. A benchmark of QC practice in the UK is presented, against which individual centres can compare their procedures, frequency of testing and acceptable tolerance values. We propose the use of internal "notification" and "suspension" levels for analysis. All surveyed centres were using recommended Codes of Practice for kV dosimetry in the UK; approximately the same number using in-air and in-water methodologies for medium energy, with two-thirds of all centres citing "clinical relevance" as the reason for choice of code. 64% of centres had hosted an external dosimetry audit within the last 3 years, with only one centre never being independently audited. The majority of centres use locally measured applicator factors and published backscatter factors for treatments. Monitor unit calculations are performed using software in only 36% of centres.
  
  
  CONCLUSIONS
  A comprehensive review of current kV practice in the UK is presented. Advances in knowledge: Data and discussion on contemporary kV radiotherapy in the UK, with a particular focus on physics aspects.
authors.affiliation: 1 Department of Medical Physics, Portsmouth Hospitals NHS Trust, Portsmouth, UK.|2 Department of Physics, Faculty of Engineering and Physical Science, University of Surrey, Guildford, UK.
authors.forename: Antony L
authors.initials: AL
authors.lastname: Palmer
authors.affiliation: 3 Radiotherapy Physics, St Bartholomew's Hospital, London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Pearson
authors.affiliation: 4 Radiotherapy Physics, The Beacon Centre, Musgrove Park Hospital, Taunton, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Whittard
authors.affiliation: 5 Medical Physics Department, Addenbrooke's Hospital, Cambridge, UK.|6 GenesisCare, Springfield Cancer Centre, Chelmsford, UK.
authors.forename: Katie E
authors.initials: KE
authors.lastname: McHugh
authors.affiliation: 7 National Radiotherapy Trials QA Group (RTTQA), Mount Vernon Hospital, Northwood, UK.|8 Radiotherapy Special Interest Group (RTSIG), Institute of Physics and Engineering in Medicine (IPEM), York, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Eaton
mesh_terms: D006801:Humans; D010825:Physics; D011786:Quality Control; D011874:Radiometry / Q000295:instrumentation* / Q000706:statistics & numerical data*; D011878:Radiotherapy / Q000295:instrumentation* / Q000706:statistics & numerical data*; D011879:Radiotherapy Dosage; D006113:United Kingdom; D016526:Workload / Q000706:statistics & numerical data*