Ultralow emittance, multi-MeV proton beams from a laser virtual-cathode plasma accelerator.

The laminarity of high-current multi-MeV proton beams produced by irradiating thin metallic foils with ultraintense lasers has been measured. For proton energies >10 MeV, the transverse and longitudinal emittance are, respectively, <0.004 mm mrad and <10(-4) eV s, i.e., at least 100-fold and may be as much as 10(4)-fold better than conventional accelerator beams. The fast acceleration being electrostatic from an initially cold surface, only collisions with the accelerating fast electrons appear to limit the beam laminarity. The ion beam source size is measured to be <15 microm (FWHM) for proton energies >10 MeV.

[Automatization and robotics of the set-up and treatment of patients irradiated for brain and base ot the skull tumors]. / Automatisation et robotisation du placement et de la mise en place des patients irradiés pour une tumeur de l'encéphale et de la base du crâne.

Progresses of the three-dimensional imageries and of the software of planning systems makes that the radiotherapy of the tumours of brain and the base of skull is increasingly precise. The set-up of the patients and the positioning of the beams are key acts whose realization can become extremely tiresome if the requirement of precision increases. This precision very often rests still on the visual comparison of digital images. In the near future, the development of the automated systems controlled by robots should allow a noticeable improvement of the precision, safety and speed of the patient set-up.