BACKGROUND The aim of this study was to assess if FDG-PET could guide dose prescription heterogeneity and decrease arbitrary location of hotspots in SBRT. METHODS For three patients with stage I lung cancer, a CT-simulation and a FDG-PET were registered to define respectively the PTVCT and the biological target volume (BTV). Two plans involving volumetric modulated arc therapy (VMAT) and simu...

We introduce an e cient predictive binary shape coding method that consists of (1) global motion estimation, (2) local motion estimation, (3) matched segment coding, and (4) residual segment coding. Global and local motion estimation use contour pel matching and knowledge of previously reconstructed contours. After motion compensation, we code the one-dimensional reference contour indices of th...

We consider the problem of assigning wavelengths to demands in an optical network of m links. We assume that the route of each demand is fixed and the number of wavelengths available on a fiber is some parameter μ. Our aim is to minimize the maximum ratio between the number of fibers deployed on a link e and the number of fibers required on the same link e when wavelength assignment is allowed ...

A fundamental problem in wireless networks is the minimum spanning tree (MST) problem: given a set V of wireless nodes, compute a spanning tree T , so that the total cost of T is minimized. In recent years, there has been a lot of interest in the physical interference model based on SINR constraints. Distributed algorithms are especially challenging in the SINR model, because of the non-localit...

Patients irradiated for left-sided breast cancer have higher incidence of cardiovascular disease than those receiving irradiation for right-sided breast cancer. Most abnormalities were in the left anterior descending (LAD) coronary artery territory. We analyzed the relationships between preoperative examination results and irradiation dose to the LAD artery in patients with left-sided breast ca...

BACKGROUND Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic-pituitary (HP) axis dysfunction. OBJECTIVE To analyze the effect of treatment modality (Linac, TomoTherapy, or gamma knife) on hypothalamic dose and correlate these with HP-axis deficits after radiotherapy. METHODS Radiation plans of pa...

High energy x-ray beam penumbra are measured using Gafchromic EBT film. Gafchromic EBT, due to its limited energy dependence and high spatial resolution provide a high level of accuracy for dose assessment in penumbral regions. The spatial resolution of film detector systems is normally limited by the scanning resolution of the densitometer. Penumbral widths (80%/20%) measured at Dmax were foun...

We evaluated the changes in the dose distribution of radiation during volumetric arc radiotherapy (VMAT), to determine the right time for adaptive replanning in prostate cancer patients with progressive weight (WT) changes. Five prostate cancer patients treated with VMAT were selected for dosimetric analysis. On the original computed tomography images, nine artificial body contours were created...

PURPOSE To report the results of dosimetric comparison between intensity-modulated radiotherapy (IMRT) using Tomotherapy and four-box field conformal radiotherapy (CRT) for pelvic irradiation of locally advanced rectal cancer. MATERIALS AND METHODS Twelve patients with locally advanced rectal cancer who received a short course preoperative chemoradiotherapy (25 Gy in 5 fractions) on the pelvi...

هدف: پژوهش حاضر با هدف تحلیل و بررسی پیامدهای شبکه‌سازی سیاسی در نظام سیاست‌گذاری سازمان‌های دولتی استان لرستان انجام پذیرفت.طراحی/ روش‌­شناسی/ رویکرد : دارای رویکردی آمیخته است که از نظر هدف، کاربردی حیث ماهیت روش، توصیفی پیمایشی است. مشارکت‌کنندگان را مدیران تشکیل می­‌دهند استفاده اصل کفایت نظری روش نمونه­‌گیری هدفمند 16 نفر آنان به عنوان اعضای نمونه انتخاب شدند. بخش کیفی برای گردآوری داده مص...