A new synchrotron radiation therapy technique with future clinical potential: minibeams radiation therapy

Several synchrotrons around the world are currently developing innovative radiotherapy techniques with the aim of palliating and possibly curing human brain tumours. Amongst them the Microbeam Radiation Therapy (MRT) and more recently the Minibeam Radiation Therapy (MBRT) showed promising results. In the MBRT, the beam thickness ranges from 500 to 700 micrometers with a separation between two adjacent minibeams of the same value, whilst in the MRT the thickness is of the order of 25 to 50 microns with a distance between adjacent microbeams in the order of 200 microns. An original method has been developed and tested at the European Synchrotron Radiation Facility (ESRF) ID17 Biomedical Beamline to produce the minibeam patterns by spatially fractionating the incoming beam by a specially developed high energy white-beam chopper. The first experimental dosimetric studies performed at the ESRF show a good agreement with the theoretical dosimetry (Monte Carlo). In addition, two irradiation configurations (interlaced minibeams and stereotactic minibeams) have been studied in order to maximize the dose depo- sited in the tumor and minimize the doses in the healthy tissues.