s. sharma

Aim is to find correlation between 2D-gamma passing rate and 3D-DVH-based pre-treatment patient-specific quality assurance.

21 head and neck and 21 pelvis patients, treated with volumetric modulated arc therapy (VMAT) were selected for this study. All patients were planned with Elekta VersaHD linear accelerator using Monaco (5.11) treatment planning system. 2D-planar dose measurements were performed with IBA-I'matriXX evolution detector-array using My-QA-Patients software. For 2D-Gamma index evaluation, 3%/3mm and 2%/2mm criteria were used. 3D-dose measurements were performed using the IBA-COMPASS system. For 3D measurement, Monaco and COMPASS doses were compared in terms of percentage dose differences to PTV and organs at risk. For PTV D95, D2, and D50 (dose received by 95%, 2%, and 50% volume), similarly for OARs D2 and D50 were noted. 3D Gamma index was also noted. Correlation coefficient and its corresponding two-tailed p-value (≤0.05, for statistically significant) were calculated for 2D-gamma passing rate and 3D Gamma index & percentage dose differences of 3D-DVH based metrics (Monaco calculated versus COMPASS measured).  Strength of correlation will be considered weak or strong based on the r -value.

2D-Gamma index passing rate was 98.6±1.8%, 92.1±7.1% and 98.5±1.3%, 93.5±4.4% for head-neck and pelvis patients (3%/3mm, 2%/2mm criteria) respectively. Percentage dose-differences for PTV D95, D2, D50 for head-neck and pelvis were: 4.22±2.09%, 4.25±2.23%, 3.93±1.59 & 0.60±1.96%, 1.53±1.64%, 1.59±1.20% respectively. Spine and brainstem D2 were -0.84±6.10%, 0.77±2.70%, bladder and rectum D50 were 3.75±3.31%, -2.19±3.60%.

  No strong correlation was observed between the 2D Gamma passing rate and 3D measurements.

Integration of Distributed Generation (DG) in the Distribution network will reduce the network expansion costs and increase the network reliability in terms of reduction in voltage magnitude deviations.This paper presents Symbiotic Organisms Search (SOS) based technique for finding out the best size and position of DG in Radial Distribution networks to improve the voltage profile and voltage security state of the Distribution network. The primary objectives of the paper are minimization of bus voltage variation and maximization of voltage stability index of the network as a multi objective optimization problem in presence of uncertainty of sources and loads. In this paper the uncertainty of solar power, wind power and load are modelled using 2m Point Estimate Method along with SOS algorithm.To show the effect of DG placement on voltage security state of Distribution system, the system is classified into three states based on the values of voltage stability index (VSI). Simulation results as obtained from two standard (IEEE) radial distribution networks prove the efficiency and accuracy of the proposed SOS method. The results of SOS based method are compared with some other techniques as found in recent literature, which shows that SOS algorithm outperforms other standard optimization techniques.

We introduce and study a new class of spaces, namely $beta-$topological vector spaces via $beta-$open sets. The relationships among these spaces with some existing spaces are investigated. In addition, some important and useful characterizations of $beta-$topological vector spaces are provided.

In this paper, a numerical solution has been developed for hollow circular cylinders made up of orthotropic material which is subjected to twist using micro polar theory. The effect of twisting moment and material internal length on hollow thick-walled circular cylinder made up of micro polar orthotropic material is investigated. Finite difference method has been used to exhibit the influence of shear moduli and material internal length on shear stresses and couple stresses. It is found that the effect of small characteristic length on shear stresses is negligible and couple stresses present its significance when characteristic length is large in solid particle. The behavior of couple stresses are nonlinear for large internal length while for small internal length couple stresses are linear in nature except near the free boundaries. Torsion in hollow cylinder made up of micro polar orthotropic play vital role in the presence of cracks and holes. Therefore, torsional analysis of hollow cylinder plays important role in the field of biomechanics.