Proton accelerators and gantries

In this chapter an overview will be given of the accelerators currently in use for proton therapy: the cyclotron and the synchrotron as well as the gantries that deliver the prothon dose to the tumor. Before dealing with the accelerators, first, the basic principles of the different dose delivery processes will be discussed. The requirements imposed by the dose delivery method have various consequences on how cyclotrons and synchrotrons are working in proton therapy. Based on a description of the working principles of the cyclotron and the synchrotron, it will be described how these requirements are implemented into the operation of the accelerators. The sections dealing with the accelerators are followed by a description of the basic principles of gantries and several examples are discussed to illustrate several concepts. These mechanical devices can rotate the last part of the beam transport system and the final dose delivery system around the patient to set the different treatment angles from which one irradiates the tumor in the patient. Finally, some of the recent developments in the accelerator field are discussed.