Dose energy dependence in proton imaging

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2011-10, Vol.652 (1), p.747-750
• Main Authors: Denyak, V.V., Paschuk, S.A., Schelin, H.R., Rocha, R.L., Setti, J.A.P., Klock, M.C.L., Evseev, I.G., Yevseyeva, O.I.
• Format: Article
• Language: English
• Subjects: Computed tomography; Density; Detectors; Dose; Energy; Energy (nuclear); Energy use; Irradiation; Proton; Proton beams; Radiography; Spectrometers
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2010.09.108

In the earliest works dedicated to proton radiography and proton computed tomography it was shown that the advantage of image creation using proton beams appears when the energy is chosen as small as possible, but enough to pass the object. This phenomenon is based on the great sensitivity of the energy flux of the proton beam in relation to the length and density of the object at the end of the proton range. However, this fact was proved experimentally only with thin detectors, such as photographic films, which detect only part of the exit energy of protons. Another method which is based on the measurement of total exit energy of protons contains two effects that act in opposite ways: the necessary irradiation dose increases when the energy of the proton is reduced. In this work, the dependence of the irradiation dose on proton initial energy was studied using analytical formulas and computer simulations. The investigation shows that the irradiation dose depends slightly on the proton energy beyond the region at the end of the proton range and increases sharply in it.