ITEP synchrotron proton beam in radiotherapy

Patients have been treated at the ITEP proton accelerator since 1969. The ITEP accelerator is a strong focusing 10 GeV proton synchrotron with internal beam intensity near 10/sup 12/ protons per pulse and 22 acceleration cycles per minute. Since only one sixteenth of the accelerated protons are used for the medical beam, medical procedures in the external beam can be pursued independently and simultaneously with physical investigations at the accelerator. The energy of the external medical beam can be varied from 70 to 200 MeV and depends upon the time of ejection. The proton beam brought out of the vacuum chamber is always monochromatic and has only a slight angular divergence, because there is no need to decelerate it by means of thick degraders. This creates appropriate conditions for forming clinically useful beams. The available intensity of the extracted beam provides a rate ranging from 1 to 100 Gy per min depending on the need, on the size of the target volume and on the shape of the dose distribution. This paper examines the dosimetry and clinical work of the ITEP synchrotron.