title: Recommendations on detectors and quality control procedures for brachytherapy beta sources.
abstract: OBJECTIVE
  It is estimated that one third of the institutes applying clinical beta sources does not perform independent dosimetry. The Netherlands commission on radiation dosimetry (NCS) recently published recommended quality control procedures and detectors for the dosimetry of beta sources. The main issues of NCS Report 14 are summarized here.
  
  
  METHODS
  A dosimetry survey was performed among 23 institutes in The Netherlands and Belgium. Well ionization chambers, a plastic scintillator, plane-parallel ionization chamber, diode and radiochromic film were used for determination of source strength (dose rate at reference distance) and uniformity of intravascular and ophthalmic sources. The source strength of multiple sources of each type was measured and compared with the source strength specified by the manufacturer.
  
  
  RESULTS
  The standard deviation of the difference between measured and specified source strength was mostly about 3%, but varied between 0.8 and 15.8% depending on factors such as source type, detector, phantom and manufacturers calibration. The average non-uniformity was about 7% for intravascular sources and 20% for ophthalmic sources. It is estimated that the total relative standard uncertainty can be kept below +/-4% (1 sigma) with all detectors tested. Maximum deviations in source strength of 10% and a non-uniformity below 10% (intravascular) and 30% (ophthalmic) are recommended.
  
  
  CONCLUSIONS
  Dosimetric and non-dosimetric quality control procedures on beta sources are recommended. They enable standardized measurements, including the determination of relative source strength and non-uniformity. Absolute calibrations depend on the future introduction of primary standards for clinical beta sources.
authors.affiliation: Department of Radiotherapy, Catharina Hospital, Eindhoven, The Netherlands. rpkollaard@zonnet.nl
authors.forename: Robert P
authors.initials: RP
authors.lastname: Kollaard
authors.forename: Wim J F
authors.initials: WJ
authors.lastname: Dries
authors.forename: Herman J
authors.initials: HJ
authors.lastname: van Kleffens
authors.forename: Tony H L
authors.initials: TH
authors.lastname: Aalbers
authors.forename: Hans
authors.initials: H
authors.lastname: van der Marel
authors.forename: Hans P A
authors.initials: HP
authors.lastname: Marijnissen
authors.forename: Marleen
authors.initials: M
authors.lastname: Piessens
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Schaart
authors.forename: Henk
authors.initials: H
authors.lastname: de Vroome
mesh_terms: D001530:Belgium; D001808:Blood Vessels; D001918:Brachytherapy / Q000295:instrumentation / Q000592:standards*; D002138:Calibration; D004867:Equipment Design; D005123:Eye; D005373:Film Dosimetry / Q000295:instrumentation; D006801:Humans; D009426:Netherlands; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care; D011786:Quality Control; D011874:Radiometry / Q000295:instrumentation; D011879:Radiotherapy Dosage / Q000592:standards*; D012588:Scintillation Counting / Q000295:instrumentation