Calibrations in radiotherapy applications

In radiotherapy applications the dosemeters and electrometers are calibrated using:

  • Air Kerma (Kair) for γ and Χ rays (the Nk calibration factor is provided) and
  • Absorbed Dose to water (Dw) for γ rays and electrons (the ND,w calibration factor is provided)

Dosimetric Quantities:

  • Air Kerma (Gy) for γ and Χ rays.
  • Air Kerma rate from 60Co: 3,9 mGys-1(*) at SCD=1m
  • Air Kerma rate from X rays: 0,1 - 10 mGys-1 at SCD=1m for various combinations of kV - HVL
  • Expanded uncertainty (**) u = 1,2% at 95% CL (k=2)
  • Absorbed dose to water (Gy) for γ rays
  • Absorbed dose to water from 60Co: 3,9 mGys-1(*) at SCD=1m
  • Range of absorbed dose in water: 2 10-2 έως 0,5 102(*) Gy
  • Expanded uncertainty (**) u = 1,4% at 95% CL (k=2)
  • Absorbed dose to water for electron beams (Gy)
  • The calibrations are performed at the user’s electron beams
  • Absorbed dose rate and range depends on the user’s linac
  • Expanded uncertainty (**) u = 2,0% at 95% CL (k=2)

(*) July 2018
(**) Best measurement capability

 Radiation sources

  • 60Co PICKER (110 TBq - April 2012)
  • X ray PANTAK (high voltage up to 225 kVp, anode W)
  • User’s linear accelerators (electron beams)

 Qualities of energies used

  •  60Co (S-Co)
  • X rays: 0,1 - 2,0 mm Cu HVL (100 - 220 kV)
  • X rays: 0,2 - 1,0 mm Al HVL (32 - 50 kV)
  • Electron beams of user’s linear accelerators: 4 - 20 MeV


  • BIPM, France, for S-Co and electron beams 4 - 20 MeV
  • PΤΒ, Germany, for low and medium energy X rays. 

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