ABSTRACT
Figure 7.1 illustrates a typical kilovolt X-ray imaging system configuration, the Hitachi image-guided proton therapy system installed at the MD Anderson Cancer Center. In this rotating gantry room, the treatment nozzle can rotate around the patient and deliver proton beams in any coplanar angle. During imaging verification, the nozzle X-ray tube can slide into the beam line and provide a “beam’s-eye-view” X-ray image. Nozzle X-rays can be used to verify beamshaping devices such as block aperture; therefore, it is necessary for it to be located near the virtual source position as the proton beam. In addition to the nozzle X-ray imaging system, a separate gantry-mounted X-ray imaging system (the cage X-ray system) perpendicular to the nozzle X-ray beam direction is provided for orthogonal/stereoscopic X-ray imaging. Due to the fact that a proton/carbon therapy gantry is much bigger and heavier than a photon therapy gantry, minimizing gantry rotation is necessary to minimize wear and tear on the machine. A dual-source orthogonal X-ray imaging system can localize a 3-D object without the
need to rotate the gantry and thus makes the imaging process more efficient.
