in this paper a novel fuzzy scheme for medical x-ray image classification is presented. in this method, any image is partitioned in to 25 overlapping subimages and then shape-texture features are extracted from shape and directional information extracted from any subimage. in the classification stage, we apply a fuzzy membership to any subimage with respect to euclidean distance between feature...

Introduction: In order to reduce patient setup error in treatment field, portal images with treatment beam (megavoltage x-ray) are widely used. These images are acquired by electronic portal imaging devices (EPID). However, portal images suffer from insufficient anatomical information, contrast, and spatial resolution, because of the fact that Compton scatter is the main photon...

During the radiotherapy process, the emergence of set-up errors is nearly inevitable. Because set-up errors were not detected and corrected daily, planned target volumes were formed by expanding the clinical target volume according to each unit's experience. We optimized the margins of clinical and planned target volumes during administration of intensity-modulated radiotherapy for nasopharynge...

BACKGROUND To analyze setup deviations using daily megavoltage computed tomography (MVCT) and to evaluate three MVCT frequency reducing protocols for gynecologic cancer patients treated with helical tomotherapy. METHODS We recorded the setup errors of 56 patients with gynecological cancer observed throughout their whole course by matching their daily MVCT with the planning CT. Systematic and ...

Currently portal imaging devices are used to obtain information on patient localization during radiation therapy treatments. Such obtained information is two dimensional in nature, limited to the plane of the captured image. It has been proposed that megavoltage computed tomography images be reconstructed to overcome this limitation. This study explores the feasibility of reconstructing tomogra...

background: the sporadic cases of radiation-activated multiple sclerosis (ms) has been previously described, with a few studies focused on the relationship between radiation and the risk of ms. the aim of our study was to evaluate the association between history of x-ray radiation and ms.   methods : this case-control study was conducted on 150 individuals including 65 ms patients and 85 age- a...

  Introduction: Arrays of segmented scintillation crystals are useful in megavoltage x-ray imaging detectors for image-guided radiotherapy. Most previous theoretical studies on these detectors have modelled only ionizing-radiation transport. Scintillation light also affects detector performance. ScintSim1, our previously reported optical Monte Carlo code for such detector...

Objective(s): Semiconductor zinc oxide nanoparticles (ZnO NPs) have unique properties, such as inherent selectivity and photosensitization effects under ultraviolet (UV) radiation. ZnO NPs serve as promising anticancer agents. However, UV radiation limits their penetration into the body. In most clinical settings, it is essential to use high-energy photons in the treatment of deep-seated tumors...

The dosimetric stability of six TomoTherapy units was analyzed to investigate changes in performance over time and with system upgrades. Energy and output were tracked using monitor chamber signal, onboard megavoltage computed tomography (MVCT) detector profile, and external ion chamber measurements. The systems (and monitoring periods) include three Hi-Art (67, 61, and 65 mos.), two TomoHDA (3...

BACKGROUND AND PURPOSE For the first time, delivered dose to the rectum has been calculated and accumulated throughout the course of prostate radiotherapy using megavoltage computed tomography (MVCT) image guidance scans. Dosimetric parameters were linked with toxicity to test the hypothesis that delivered dose is a stronger predictor of toxicity than planned dose. MATERIAL AND METHODS Dose-s...