National Physical Laboratory

Audits: Non-reference dosimetry

Non-reference dosimetry auditsIMRT audit

NPL has played a major role in the recent IPEM UK National IMRT dosimetry audit. NPL alanine dosimeters were used to provide absolute dose measurements, which were combined with relative dose distributions from films to give an overall picture of performance. 58 centres participated and a total of 78 plans were audited.

Rotational therapy audit

A national audit is currently being carried out for rotational techniques (VMAT, RapidArc, TomoTherapy) in collaboration with the NCRI Radiotherapy Trials QA group, IPEM and the Royal Surrey County Hospital. This audit has also piloted the use of an ion chamber array such that absolute dosimetry can be carried out with suitable spatial resolution for this complex technique.

Stereotactic Ablative Body Radiotherapy (SABR/SBRT) audit

An audit is currently under development to support the implementation of SABR techniques for various clinical sites in UK hospitals. Alanine pellets will be used to make absolute dosimetry measurements in the tumour.

HDR brachytherapy audit

NPL are currently collaborating in the development of an audit for the measurement of the reference air kerma rate of HDR Ir-192 brachytherapy sources. The audit will be based on measurements made with a well-type ionisation chamber as recommended in the recently published IPEM HDR brachytherapy code of practice (Bidmead et al. 2010 Phys. Med. Biol. 55 3145-3159). Work is also being carried out to develop a suitable phantom.


Customer Services tel: +44 20 8943 8695

Last Updated: 31 Jul 2012
Created: 31 Jan 2011


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