The physical separation between the LET associated with the ultimate relative biological effect (RBE) and the maximum LET in a proton or ion beam.

摘要: Purpose To identify the relative positions of ultimate RBE, at a LET value LETU (where LET-RBE turnover point occurs independently dose), and maximum (LETM) for range ions from protons to Iron ions. Methods For relativistic velocities (β), kinetic energies, values ranges each ion are obtained using SRIM software. helium ions, changes with β plotted LETM is compared LETU. all studied residual particles subtracted provide physical separation (S) between LETM. Results Graphical methods used show above parameters studied, energies which higher than those LETM, so maximal RBE proximal Bragg peak individual not beyond it, as commonly supposed. The distance S, appears increase linearly atomic charge Z. Conclusions lighter elements, carbon S sufficiently small (less tolerance/accuracy radiation treatments) will probably influence therapeutic decisions or outcomes. Z numbers such Argon Iron, larger several centimetres occur, may have implications only in any proposed beams but also very low doses encountered protection where few cells that irradiated typically be traversed by single particle.