The expression of survival factors for radiation damaged cells is based on probabilistic assumptions and experimentally fitted for each tumor, radiation and conditions. Here we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypoth...

During the delivery of advanced radiotherapy treatment techniques modulated beams are utilised to increase dose conformity across the target volume. Recent investigations have highlighted differential cellular responses to modulated radiation fields particularly in areas outside the primary treatment field that cannot be accounted for by scattered dose alone. In the present study, we determined...

PURPOSE This study investigated the trade-off in tumor coverage and organ-at-risk sparing when applying dose escalation for concurrent chemoradiation therapy (CRT) of mid-esophageal cancer, using radiobiological modeling to estimate local control and normal tissue toxicity. METHODS AND MATERIALS Twenty-one patients with mid-esophageal cancer were selected from the SCOPE1 database (Internation...

There is strong evidence that ionizing radiation increases cancer risks at high doses (e.g., >1 Gy), and persuasive, if controversial, epidemiological evidence that cancer risks are increased at low doses ( 10 mGy). Discussed here are the issues related to extrapolating radiation risks from low radiation doses to very low doses (<1 mGy) — for which purpose we are forced to rely on radiobiologic...

Gliomas are malignant brain tumors responsible for 50% of primary human cancer cases. They have a combination rapid growth and invasiveness, high fatality rates with median survival time one year. Mathematical models that describe its helped to improve treatment. In this paper, combined model formed by terms two other known in the literature is analyzed. The Reactive-Advective-Diffusive partial...

In this paper we shall concentrate on designing a mathematical model of the recombination and diffusion of the radicals formed when a radioactive particle passes through the cell. This process is described by a system of partial differential equation in three space dimension. We shall demonstrate how to transform this problem to one space variable and propose a method how to solve it. Introduct...

Radiotherapy techniques in the last decade evolved to the stage where the potential dose distribution significantly differs from earlier practices. Rotational IMRT, robotic radiotherapy or proton radiotherapy enables extremely precise dose delivery to target volumes, on the other hand, these techniques can yield a number of problems. As for photon radiotherapy, this concerns primarily the effec...

Recent developments in microbeam technology have made drastic improvements in particle delivery, focusing, image processing and precision to allow for rapid advances in our knowledge in radiation biology. The unequivocal demonstration that targeted cytoplasmic irradiation results in mutations in the nuclei of hit cells and the presence of non-targeted effects, all made possible using a charged ...

Lymphocyte transforming properties of B95-8 strain Epstein-Barr virus (EBV) are very sensitive to inactivation by either UV or X irradiation. No dose of irradiation increases the transforming capacity of EBV. The X-ray dose needed for inactivation of EBV transformation (dose that results in 37% survival, 60,000 rads) is similar to the dose required for inactivation of plaque formation by herpes...

The radiobiological effects of highly-charged-ion beams are of interest for tumortherapy and for radioprotection in space. In tumor therapy, high-energy protons and carbon ions exhibit an inverse dose profile, i.e. an increase of energy deposition with penetration depth. This allows a greater tumor dose for protons and carbon ions than for photons. In addition, for the heavier carbon ions, this...