Therapy of glioblastoma has been very problematic with disappointing results using multiple therapeutic approaches. In general, glioblastomas are considered radioresistant tumors with different radiation modalities failing to control them in the clinic. However a comprehensive and detailed analysis of the radiosensitivity of glioblastoma cells has not been performed. We now present such an anal...

Tissue effects of radiation exposure are observed in virtually all normal tissues, with interactions when several organs are involved. Early reactions occur in turnover tissues, where proliferative impairment results in hypoplasia; late reactions, based on combined parenchymal, vascular, and connective tissue changes, result in loss of function within the exposed volume; consequential late effe...

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...

Radiation therapy is an important local cytotoxic modality for cancer treatment whose aim is to control the disease while minimising damage to normal tissue. The combination of different treatment modalities offers a more effective cure and reduction in normal tissue toxicity. However, the differences in genetic profiles can cause diverse treatment outcomes. Multidisciplinary research, where te...

A new expression for the radial dose distribution, tested against available data, and yielding good agreement with enzyme and virus cross sections, is used to calculate cellular inactivation cross sections from track theory models and parameters. We use a cellular model and radiosensitivity parameters, fitted to HILAC data 15 years ago, to represent mammalian cells irradiated at the UNILAC. The...

Purpose: Stereotactic body radiation therapy (SBRT) has emerged as a standard treatment modality for medically inoperable early-stage lung cancer patients. The aim of this paper is to calculate radiobiological parameters for a sample of 39 patients who underwent lung SBRT. Materials and Methods: For SBRT, a typical regimen of 50 Gy in 4 5 fractions results in local tumor control rates around 99...

Stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiation therapy (SABR), are rapidly becoming accepted practice for the radiation therapy of certain tumors. Typically, SRS and SBRT involve the delivery of 1 or a few large-dose fractions of 8 to 30 Gy per fraction: a major paradigm shift from radiation therapy practice over the...

Historically it has been shown repeatedly that single high doses of radiation do not allow a therapeutic differential between tumor and critical normal tissues but dose fractionation does. The purpose of conventional dose fractionation is to increase dose to the tumor while preserving normal tissue function. Tumors are generally irradiated with 2Gy dose per fraction delivered daily to a more or...