PURPOSE The aim of this study is to ascertain the subsequent radiobiological impact of using a consensus guideline target volume delineation atlas. MATERIALS AND METHODS Using a representative case and target volume delineation instructions derived from a proposed IMRT rectal cancer clinical trial, gross tumor volume (GTV) and clinical/planning target volumes (CTV/PTV) were contoured by 13 ph...

Classical models used in radiotherapy typically assume that after treatment all surviving cells have a constant and homogeneous sensitivity during the treatment period. In Keinj et al. (2010), a multinomial model based on a discrete-time Markov chain able to take into account both cell repair and cell damage heterogeneity due to radiations has been proposed. In this paper, we introduce the noti...

Objectives: The monitoring of cancer treatment response to chemotherapy is considered an essential strategy for follow-up of patients. The aim of this study was to evaluate the use of 99mTc-glucarate as a radiotracer for in vivo quantification and visualization of necrotic area and therapeutic effect of paclitaxel in ovarian cancer xenografted nude mice. Materials and Methods: After implantatio...

Objective: Purposes of this work were i) to develop an in silico model tumor response radiotherapy, ii) perform exhaustive sensitivity analysis order iii) propose a simplified version and iv) predict biochemical recurrence with both the comprehensive reduced model. Methods: A multiscale computational radiotherapy was developed. It integrated following radiobiological mechanisms: oxygenation, in...

Purpose. Our purpose was to discuss the optimal treatment and outcomes for patients with skull base chordomas. Methods. We reviewed the pertinent literature for this study. Results. Skull base chordomas usually arise in the clivus and are rarely completely resectable. Therefore, most are treated with radiotherapy (RT). Because of the risk of severe late complications, the dose is often limited ...

Ab~lraet--Methods for design of residence probability (RP) controllers for linear stochastic systems are developed. The design of RP controllers requires the selection of a controller gain and an initial 'lock in' set. The controller gain is obtained by solving a Riccati equation and the initial set is obtained by solving a Liapunov equation. Examples illustrating the suggested design procedure...

Two bar-press experiments with rats tested the rule that reducing expectation of reward increases the variation from which reward selects. Experiment 1 used a discrete-trial random-interval schedule, with trials signaled by light or sound. One signal always ended with reward; the other signal ended with reward less often. The 2 signals were randomly mixed. Bar-press duration (how long the bar w...

Introduction: Pixel value in computed tomography (CT) gives the average linear attenuation coefficient of the scanned material in the path of the x-ray beam, being normalized to that of water. It is known that attenuation coefficient or HU value is a function of the chemical characteristic of the material and of the x-ray energy. The CT image shows the HU value by a shade of gr...