The ASN adopts a position on small-beam radiotherapy treatments (radiosurgery)

On 25 June 2009, the College of the ASN adopted a position on:

• the safety of small-beam (or “mini-beam”) radiotherapy treatments for localized treatment of small lesions, most frequently intracranial lesions; and
• the precision of the procedures used for dosimetric characterisation of such beams.

Following a radiotherapy accident at Rangueil hospital in Toulouse, and a report from the Institute for Radiation Protection and Nuclear Safety (IRSN) that questioned the safety of such treatments in light of the uncertainty of the measurements performed when calibrating the mini-beams, the ASN convened the Permanent Group of Experts on Radiation Protection for Medical and Medico-legal uses of ionizing radiation (GPMED).

Having considered the opinion issued by GPMED on 24 March 2009, the ASN has decided not to restrict the use of mini-beams in stereotactic radiotherapy treatments.

However, in order that the precision of the beam characterisation procedures might be improved in future, the ASN has urged the International Atomic Energy Agency (IAEA) to publish internationally approved calibration protocols for mini-beams as soon as possible, and asked the national metrology research centre for ionizing radiation, the Laboratoire National Henri Becquerel in Saclay, near Paris, to undertake metrological research into small-size photon beams as a matter of priority.

Pending the results of this work, the ASN and the French Health Products Safety Agency (AFSSAPS) will be making national “best practice” recommendations concerning the dosimetric measurement of stereotactic radiotherapy systems to interested radiotherapy centres. These recommendations were established on the basis of expert assessments conducted by the IRSN, in conjunction with medical radiological physics professionals.

The ASN reaffirms the need to define with precision the optimum conditions for the performance of intracranial and extracranial stereotactic radiosurgery and the related medical radiological physics, and is undertaking an expert study on the subject.