18FDG et radiothérapie externe,le point de vue du radiothérapeute.: Application des techniques de fusion d’images à la radiothérapie des carcinomes bronchiques

The prognosis of patients with localized non-small-cell lung carcinoma and treated with radiation therapy remains poor. The three-dimensional conformational radiotherapy aims to increase the dose of radiation at the tumor volume to increase the local control, while sparing the healthy tissue neighborhood. The reduction of the safety margins and the irradiated volumes obliges to determine with most acute precision the exact tumor volume. However, the scanner alone is insufficient, particularly at the mediastinal level and at a distance. The positron emission tomography allows distinguishing a biological tumor volume. It helps to define the lung tumor volume, especially when the tumor is accompanied by atelectasis, and to recover the lymph node staging at the mediastinal level and at a distance. Even if the sensibility and the specificity are not 100 %, positron emission tomography now becomes essential before considering an escalation of thoracic radiation dose.     

Computer programs for single channel kinetic analysis

Programs are represented that permit us to solve the following three problems of single channel kinetic activity: 1) to fulfill a preliminary analysis of single channel activity, i.e., to estimate the minimum number of agonist molecules that bind with a channel structure, the minimum number of open and closed kinetic states of the channel, and possible connections between these states, to check the condition of thermodynamic equilibrium and adequacy of a Markovian assumption for modeling of the channel kinetics; 2) to select the model of channel gating: for a given number of kinetic states, the potential models that permit us to fit a list of dwell-times observed in an experiment are examined; the model is selected by a criterium of the maximum likelihood; 3) to simulate the response to a rapid change of the agonist concentration of single channels that demonstrate processes of adaptation or inactivation.