نتایج جستجو برای: radiobiological modeling
تعداد نتایج: 390526 فیلتر نتایج به سال:
The increasing utilization of charged particle beams for therapeutic purposes requires designing novel detector systems which shall be capable of assessing radiation quality for a diversity of ion species. It is shown that the pattern of energy deposition in thermoluminescent phosphors and biological tissue contains conceptual parallels. The correlation of physical and radiobiological parameter...
Selecting optimal doses for radiosurgery requires a thorough consideration of existing dose-response data for radiation injury of brain and surrounding structures and of the doseresponse for the desired endpoint (tumor control, obliteration of a vascular malformation, relief of trigeminal neuralgia, etc.). This paper reviews the radiobiological and physics principles that should be considered i...
The micro-irradiation technique continues to be highly relevant to a number of radiobiological studies in vitro. In particular, studies of the bystander effect show that direct damage to cells is not the only trigger for radiation-induced effects, but that unirradiated cells can also respond to signals from irradiated neighbours. Furthermore, the bystander response can be initiated even when no...
From cellular radiosensitivity parameters and theoretical particle-energy spectra in tissue, of the secondary particles from neutron and negative pion irradiations, RBE-Dose relations have been calculated. The theoretical results are compared with clinical and radiobiological data for normal tissue, tumours and cells in culture. Formulae for calculation, cellular parameters and the needed prope...
The use of improved technology has fostered increasing interest in hypofractionated radiation therapy for prostate cancer. There also is convincing evidence that an unusual aspect of prostate cancer radiobiology allow a different approach to dose escalation that is radiobiological in nature. The aim of this paper is to explain the rationale behind hypo fractionated high -dose intensity -modulat...
The expression of survival factors for radiation damaged cells is currently 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 c...
For efficient application of protons and light ions in radiotherapy, detailed knowledge and realistic models of the corresponding radiobiological mechanism are necessary. Basic characteristics of this mechanism have been represented within a probabilistic two-stage model. The processes that occur immediately after the traversals of individual particles and the response of cell to the total dama...
Ionizing radiation at low LET is more effective in the presence of oxygen than in its absence in producing most biological effects. Most experimental radiobiological irradiations are conducted in the presence of oxygen at sufficient concentration to produce a “full oxygen effect”. To understand the full oxygen effect it is helpful to review the traditional definition of OER, which is the ratio ...
Radiation effects in pine forest Influence of IR on forest ecosystems most clearly revealed itself near the Chernobyl NPP (ChNPP), where magnitudes of absorbed doses reached 'lethal' values, as applied to conifers. Main contribution to absorbed dose was due to beta-radiation of short-living radionuclides. To largest extent the radiobiological effects appeared at injured plantations of pines and...
BACKGROUND To evaluate the cytotoxic effect of carbon ion radiotherapy and chemotherapy in glioblastoma cells in vitro. METHODS AND MATERIALS The human glioblastoma (GBM) cell line U87 was irradiated with photon radiotherapy (RT) doses of 2 Gy, 4 Gy and 6 Gy. Likewise, irradiation with carbon ions was performed with single carbon doses of 0.125, 0.5, 2 and 3 Gy. Four chemotherapeutic substanc...
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