Medical Applications

Accelerators have recently been used in cancer radiation treatment instead of the application of X-rays. The main limitation of the use of X-rays is that they deposit most of their energy where they originally enter the body, and in order not to damage healthy tissue, the overall dose has to be rather limited. On the other hand, particle beams offer the advantage of depositing most of the energy in a rather narrow region just before they are stopped in the tissue. 
 
 

The four figures compare the dose received by different parts of the body by X-ray irradiation (top) and proton irradiation (bottom). The left images show the application of the beam from a single direction, and the right images show the more advantageous application from several directions. In both cases, the undesireable irradiation of healthy tissue is significantly reduced by the use of protons, allowing for a more selective and effective treatment of the cancer tissue. 
Two particle beam treatment facilities, the proton therapy system at Loma Linda university (left), and the neutron system at Harper Hospital, which is based on a cyclotron developed at Michigan State University (right).

 
Irradiation by ion beams is also used in different medical applications; wear and corrosion and hence failure of surgical steel can be reduced by nitrogen implantation through bombardment, as in the artificial femur shown on the right.