Tumor therapy and track structure

Abstract

The elevated relative biological effectiveness (RBE) of heavy ions like carbon is the main reason for their use in radiotherapy and is due to the microscopic distribution of dose inside each particle track. High local doses produce lesions that are expected to have a diminished possibility of repair. Thus, RBE depends on track structure and on the biological repair capacity of the tissue that is affected by the irradiation. For tumor treatment planning with heavy ions, the beam quality and the tissue sensitivity have to be taken into account. Using the dependence of radial dose distribution on particle energy and atomic number on the physical side and x-ray dose response for the repair capacity on the biological side, the response to particle irradiation can be calculated in the local effect model (LEM) and used for treatment planning. This article traces the route from electron emission as the basis of track structure to the RBE calculation and the application in treatment planning.

Temporal Lobe Reactions After Radiotherapy With Carbon Ions: Incidence and Estimation of the Relative Biological Effectiveness by the Local Effect Model

“…At the Gesellschaft für Schwerionenforschung (GSI, Darmstadt, Germany), the RBE is calculated at each voxel within the treatment field by using the local effect model (LEM) (6)(7)(8)(9). The model has been tested in animal experiments, but further clinical validation of the model is still needed (5).…”

Time-dependent density-functional-theory investigation of the collisions of protons and α particles with uracil and adenine

“…While many of the biological consequences of radiation have been observed and tested on the macro scale, including cancer, birth defects, heart disease, and central nervous system diseases [4,23,24], the experimental limitations have, until recently, prevented direct observation of its mechanisms and immediate e↵ects on the molecular scale. This topic is currently of particular interest to the advancement of ion radiation therapy, which has emerged as an outstanding candidate for cancer treatment since it allows for precise dose localization [25][26][27][28]. This is because radiation damage caused by charged particles follows the Bragg curve [28][29][30], which is caused by a resonance between the ion's speed and the electrons in the medium.…”

Towards biology-oriented treatment planning in hadrontherapy

“…(9,10) . Based on the Bragg peak positions reported in these experiments (which differ from those of Ref.…”

“…MeV/u, 2x10 7 cm -2 (solid line, full symbols) and 5x10 7 cm -2 (dotted line, empty symbols). Model predictions compared to experimental data (9,10) .…”