ABSTRACT A light bridge is a magnetic intrusion into sunspot, it interacts with the main field and excites variety of dynamical processes. In letter, we studied connectivity between coronal loops rooted at sunspot. We used data Atmospheric Imaging Assembly onboard Solar Dynamics Observatory(SDO) to study features sunspots bridges. It found that if anchors umbra-penumbra boundary, could not be f...

introduction the gamma knife system is designed solely for non-invasive treatment of brain disorders, and it benefits from stereotactic surgical techniques. dose calculations required in the system are performed by gammaplan code; in this code, brain tissue is considered uniform. in the present study, we evaluated the effect of gamma knife system on the obtained dose through simulating a real h...

This paper introduces a new concept within shadow segmentation for usage in shadow removal and augmentation through construction of an alpha overlay shadow model. Previously, an image was considered to consist of shadow and non-shadow regions. We construct a model that accounts for sunlit, umbra and penumbra regions. The model is based on theories about color constancy, daylight, and the geomet...

Introduction: Treatment with megavoltage electron beams is ideal for irradiating superficial tumors because of their limited range in tissues. However, for electron treatment of extended areas, such as the chest wall, two or more adjacent fields can be used. Abutment of these fields may lead to significant dose in homogeneities in the junction region. The aim of this study is to offer a new met...

The concept of the ischemic penumbra was formulated 30 years ago based on experiments in animal models showing functional impairment and electrophysiological disturbances with decreasing flow to the brain below defined values (the threshold for function) and irreversible tissue damage with the blood supply further decreased (the threshold for infarction). The perfusion range between these thres...

Background The progression of FLAIR white matter hyperintensities (WMHs) on MRI heralds vascular-mediated cognitive decline. Even before WMH progression, adjacent normal appearing (NAWM) already demonstrates microstructural deterioration diffusion tensor imaging (DTI). We hypothesized that elevated DTI free water (FW) would precede implicating interstitial fluid accumulation as a key pathologic...

Dear Editor, Jung et al. [1] are to be congratulated on definitively demonstrating what could only be surmised in the past— that intraocular angiogenesis after central retinal artery occlusion (CRAO) occurs in that small proportion of cases wherein retinal reperfusion fails to materialize [2,3]. However, your contributors appear to be unsure as to the mechanism whereby neovascularisation of the...

Micro-multileaf collimator systems coupled to linear accelerators for radioneurosurgery treatments require a rigorous dosimetric characterization in order to be used in 3D conformal and intensity modulated stereotactic radiosurgery and radiotherapy applications. This characterization involves high precision measurements of leaf transmission, leakage and beam penumbra through the collimation sys...