National Physical Laboratory

Alanine reference dosimetry service for radiotherapy

NPL's mailed alanine reference dosimetry service for cobalt-60 gamma-ray and megavoltage photon beams.

Phantom plate showing alanine dosemeters and an ionisation chamber
Phantom plate showing alanine
dosemeters and an ionisation chamber

NPL operates a mailed alanine reference dosimetry service for 60Co γ-ray and megavoltage photon beams.

A phantom set enables the small alanine dosimeters to be irradiated alongside ionisation chambers in radiotherapy photon beams. On return to NPL, the dose received by the alanine is determined by measuring the concentration of stable free radicals using electron paramagnetic resonance spectrometry.

Features include:

  • Convenient mailable solid-state alanine dosimeter (cylinder 11.5 mm diameter, 17 mm height)
  • Near tissue equivalence and very low energy dependence
  • Precision of single dosimeter measurement better than ±1% at 1σ for doses between 5 Gy and 10 Gy
  • Internationally recognised calibrations traceable to NPL, the UK's national standards laboratory
  • Can be used in stacks to give dose distribution information
  • Can be used in small fields, e.g. as used in IMRT
  • Availability on demand throughout the year

We can provide a variety of holders and phantoms in which to place the alanine pellets. Our service is complemented by a team of experienced dosimetry specialists providing expert advice to help you achieve maximum accuracy with your dose measurements.


Customer Services tel: +44 20 8943 8695

Last Updated: 23 May 2012
Created: 31 Jan 2011


Please note that the information will not be divulged to third parties, or used without your permission