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[en] The aim of radiotherapy treatment is to deliver radiation dose to various malignant or non-malignant targets efficiently, accurately and safely. As the number of radiation incidences reported due to human errors, separate patient dose verification (in-vivo) is required during the actual treatment delivery in external beam radiotherapy (EBRT). In this paper, we will be discussing how we established in-vivo dosimetry (using p-type silicon diodes) technique by measuring various correction factors
[en] The TomoTherapy HI-ART II helical tomotherapy system (TomoTherapy, Inc., Madison, WI, USA) achieves highly conformal dose distributions using a helical-CT like IMRT delivery paradigm. Daily image-guidance is provided by an integrated megavoltage CT system that is used to reduce setup errors allowing more accurate targeting of dose to the intended volume. The complex dynamic delivery requires pretreatment patient specific delivery quality assurance (DQA) to ensure accurate delivery. Low, et al., developed a technique to simultaneously incorporate both absolute dose variation ΔD and DTA values into the quality index called gamma. We used the VanDyk criteria (3%/3mm) in our analysis. In this investigation, we reviewed the patient specific delivery quality assurance for the patients of TomoTherapy HI-ART II helical tomotherapy system
[en] The outcome of stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) in both benign and malignant tumors within the cranial region highly depends on precision in dosimetry, dose delivery and the accuracy assessment of stereotaxy associated with the unit. The frames BRW (Brown-Roberts-Wells) and GTC (Gill- Thomas-Cosman) can facilitate accurate patient positioning as well as precise targeting of tumours. The implementation of this technique may result in a significant benefit as compared to conventional therapy. As the target localization accuracy is improved, the demand for treatment planning accuracy of a TPS is also increased. The accuracy of stereotactic X Knife treatment planning system has two components to verify: (i) the dose delivery verification and the accuracy assessment of stereotaxy; (ii) to ensure that the Cartesian coordinate system associated is well established within the TPS for accurate determination of a target position. Both dose delivery verification and target positional accuracy affect dose delivery accuracy to a defined target. Hence there is a need to verify these two components in quality assurance protocol. The main intention of this paper is to present our dose delivery verification procedure using cylindrical wax phantom and accuracy assessment (target position) of stereotaxy using Geometric Phantom on Elekta's Precise linear accelerator for stereotactic installation
[en] The effect of low energy argon plasma treatment on the surfaces of polyethylene terephthalate (PET) was investigated by means of contact angle measurement, X-ray photoelectron spectroscopy (XPS), Vickers’ microhardness indentation and atomic force microscopy (AFM). It was observed that the surface free energy (SFE) changes from 42.1 mJ/m2 to 85.1 mJ/m2 with the increase of plasma treatment time and the corresponding contact angle changes from 60o to 15o. The increase in SFE after plasma treatment is attributed to the functionalization of the polymer surface with hydrophilic groups. The XPS analysis shows the increase in C–O and C=O groups after plasma treatment of the polymer surface. The microhardness of the film increases with the treatment time. This may be attributed to the cross linking effect at the surface. Atomic force microscopy (AFM) reveals that average surface roughness increases from 5.8 nm to 49.7 nm as treatment time increases.