The brachytherapy process requires consistent reference dosimetry that is traceable to metrological primary standards and common procedures to be followed for reference dosimetry globally. The Code of Practice is addressed to both Secondary Standards Dosimetry Laboratories and hospitals. It fulfills the need for a systematic and internationally unified approach to the calibration and use of vented well-type re-entrant ionisation chambers in determining the strength of brachytherapy sources with intensities measurable by such detectors. The dosimetry formalism as well as common procedures for calibration, reference dosimetry, reference-class instrument assessment and commissioning of the well-type ionisation chamber system are provided.

• 1. INTRODUCTION
  • 1.1. Background
  • 1.2. Objectives
  • 1.3. Scope
  • 1.4. Structure
• 2. BRACHYTHERAPY RADIOACTIVE SOURCES
  • 2.1. Main photon-emitting radioactive sources
  • 2.2. Beta-emitting radioactive sources
  • 2.3. Other photon-emitting radioactive sources
• 3. QUANTITIES AND UNITS
  • 3.1. Reference air kerma rate and air kerma strength
  • 3.2. Absorbed dose to water and the dose rate constant
  • 3.3. Recommended calibration quantities
    • 3.3.1. Photon-emitting radioactive sources
    • 3.3.2. Beta-emitting radioactive sources
  • 3.4. Nuclear decay: half-lives and date and time standard
    • 3.4.1. Reference half-lives
    • 3.4.2. Reference date and time standard
• 4. INSTRUMENTATION
  • 4.1. The re-entrant well-type ionization chamber dosimetry system
    • 4.1.1. The well-type chamber
    • 4.1.2. Well-type chamber source holders
    • 4.1.3. Electrometers, cables and connectors
    • 4.1.4. Connectors and extension cable
  • 4.2. Reference-class well-type ionization chambers
    • 4.2.1. Specification of reference-class well-type chambers
    • 4.2.2. Available reference-class well-type chambers
    • 4.2.3. Commissioning of well-type chambers
  • 4.3. HDR brachytherapy delivery equipment
  • 4.4. Instruments for air density and relative humidity measurements
• 5. DOSIMETRY FRAMEWORK
  • 5.1. Classification of instruments and standards
  • 5.2. The international measurement system
    • 5.2.1. The role of PSDLs
    • 5.2.2. The role of SSDLs
    • 5.2.3. Recognition of calibration services
    • 5.2.4. Role of the manufacturer
• 6. ESTABLISHMENT AND DISSEMINATION OF CALIBRATION QUANTITIES
  • 6.1. Establishment of primary calibration standards
  • 6.2. Calibration of the well-type chamber dosimetry system
    • 6.2.1. SSDL well-type chamber dosimetry system calibration
    • 6.2.2. Hospital well-type chamber dosimetry system calibration
  • 6.3. Request for dosimetry system calibration
  • 6.4. Information provided in the calibration certificate of the dosimetry system
• 7. DOSIMETRY FORMALISM
  • 7.1. Formalism based on standards of reference air kerma rate
    • 7.1.1. Reference conditions
    • 7.1.2. Influence quantities
  • 7.2. Source model correction factor
  • 7.3. Source decay correction factor
  • 7.4. Formalism based on standards of absorbed dose rate to water
  • 7.5. Determination of the reference source strength
  • 7.6. Calibration of the well-type chamber dosimetry system
  • 7.7. Cross-calibration of the well-type chamber dosimetry systems
• 8. CODE OF PRACTICE FOR WELL-TYPE CHAMBER CALIBRATION AND SOURCE STRENGTH MEASUREMENT
  • 8.1. Experimental set-up and equipment preparation
  • 8.2. Well-type chamber measurements
    • 8.2.1. Sweet spot determination
    • 8.2.2. Measurement techniques for current
    • 8.2.3. Correction for influence quantities
  • 8.3. Source model correction for air kerma rate measurements
  • 8.4. Short term repeatibility checks of the well-type chamber instrumentation
  • 8.5. Long term stability checks of the well-type chamber instrumentation
    • 8.5.1. Redundant well-type chamber dosimetry system method
    • 8.5.2. Check source method
    • 8.5.3. External radiation beam method
    • 8.5.4. HDR source method
  • 8.6. Source exchange and the vendor source certificate
    • 8.6.1. Ordering and exchanging a source
    • 8.6.2. The role of the vendor source certificate at the hospital
• 9. ESTIMATED UNCERTAINTIES IN THE DETERMINATION OF THE REFERENCE AIR KERMA RATE UNDER REFERENCE CONDITIONS
• 10. APPLICATION OF REFERENCE QUANTITIES IN THE HOSPITAL
  • 10.1. Photon-emitting radioactive sources
  • 10.2. Beta-emitting radioactive sources
  • 10.3. Brachytherapy source registries
  • 10.4. Typical uncertainties in patient dosimetry
• Appendix I ANTIQUATED QUANTITIES AND UNITS
• Appendix II ESTABLISHMENT OF PRIMARY CALIBRATION STANDARDS FOR RADIOACTIVE BRACHYTHERAPY SOURCES
• Appendix III X-RAY EMITTING ELECTRONIC SOURCES
• Appendix IVOTHER DETECTOR SYSTEMS FOR BRACHYTHERAPY
• Appendix V THE AAPM TG-43 ALGORITHM FOR DOSE DISTRIBUTION CALCULATION IN BRACHYTHERAPY
• Appendix VIEXPRESSION OF UNCERTAINTIES
• REFERENCES
• ABBREVIATIONS
• CONTRIBUTORS TO DRAFTING AND REVIEW