Image Resolution of Proton Radiography by Using a Range Modulation Technique

In proton therapy, the use of proton radiography has advantages in treatment planning and patient positioning in comparison with conventional X-ray images, although multiple Coulomb scattering of a proton beam in a medium limits the image resolution. We have investigated the factors affecting the resolution of a proton radiograph with experiments and Monte Carlo simulations. We use a range-modulation technique for the proton beam to produce images on a scintillating screen. The main factor affecting the density resolution for the adopted method is the slope in the depth-dose distribution curve of a beam. Numerical works were performed to explore different shapes of the dose curves. In addition, multiple scattering effects bring about blurring and edge effects on the image and appear as a function of the distance between the object and the image planes. The relationship between resolution and the distance were studied, along with a filtering method to sharpen the image. KCI Citation Count: 1