We proposed to perform a basic dosimetry commissioning on a new imager sys-tem, the Varian aS1200 electronic portal imaging device (EPID) and TrueBeam 2.0 linear accelerator for flattened (FF) and flattening filter-free (FFF) beams, then to develop an image-based quality assurance (QA) model for verification of the system delivery accuracy for intensity-modulated radiation therapy (IMRT) treat-...

The increasing popularity of intensity-modulated arc therapy (IMAT) treatments requires specifically designed linac quality assurance (QA) programs. Gantry angle is one of the parameters that has a major effect on the outcome of IMAT treatments since dose reconstruction for patient-specific QA relies on the gantry angle; therefore, it is essential to ensure its accuracy for correct delivery of ...

1,25 dihydroxyvitamin D (1,25(OH)2D), the active metabolite of vitamin D, and calcium regulate epidermal differentiation. 1,25(OH)2D exerts its effects through the vitamin D receptor (VDR), a transcription factor in the nuclear hormone receptor family, whereas calcium acts through the calcium sensing receptor (Casr), a membrane bound member of the G protein coupled receptor family. We have deve...

abstractbackground: although electronic portal imaging devices (epids) have originally developed for positioning verification, they can also be used for dosimetric purposes. in the current work, the dose response of minimum detectable thickness of a scanning liquid filled ion chamber epid, slic-epid, and the variation of transmitted dose with the shift of inhomogeneity inside of phantom was als...

A patient specific quality assurance (QA) should detect errors that originate anywhere in the treatment planning process. However, the increasing complexity of treatment plans has increased the need for improvements in the accuracy of the patient specific pretreatment verification process. This has led to the utilization of higher resolution QA methods such as the electronic portal imaging devi...

PURPOSE To develop a method for removing the effect of support arm backscatter from Varian electronic portal imaging devices (EPIDs), improving the dosimetric abilities of the imager. METHODS A physical, kernel based model of the backscatter signal produced during an exposure was developed. The model parameters were determined through an optimization process, comparing measured images without...

Introduction: Electronic portal imaging devices (EPIDs) provide two- and three-dimensional planar and volumetric cone beam images to improve the accuracy of radiation treatment delivery. Periodic quality assurance (QA) of EPIDs is essential for dosimetric verification in radiotherapy. In this study, a QA program was implemented to evaluate the function of the EPID to be confident in applying co...

Electronic portal imaging devices (EPIDs) have been the preferred tools for verification of patient positioning for radiotherapy in recent decades. Since EPID images contain dose information, many groups have investigated their use for radiotherapy dose measurement. With the introduction of the amorphous-silicon EPIDs, the interest in EPID dosimetry has been accelerated because of the favourabl...

MrsD from Bacillus sp. HIL-Y85/54728 is a member of the HFCD (homo-oligomeric flavin-containing Cys decarboxylases) family of flavoproteins and is involved in the biosynthesis of the lantibiotic mersacidin. It catalyses the oxidative decarboxylation of the C-terminal cysteine residue of the MrsA precursor peptide of mersacidin, yielding a (Z)-enethiol intermediate as the first step in the forma...