945 resultados para Volumetric ring


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Signatur des Originals: S 36/F09791

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Signatur des Originals: S 36/F09792

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Signatur des Originals: S 36/F10234

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Signatur des Originals: S 36/F10697

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Signatur des Originals: S 36/F10710

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Signatur des Originals: S 36/F12383

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Effective family support strategies offer early intervention and help for families and children at risk of experiencing social exclusion and maltreatment. This paper reports a study which evaluated client outcomes from participation in an Intensive Family Support Service by comparing views of workers and service users on perceived benefits. It profiles the characteristics and circumstances of families recruited to service, services and interventions delivered and the potential of IFSS to lead to safe and positive outcomes for children and families. Findings discussed highlight the individualized and collaborative approach and the high degree of engagement with service users that facilitated gains in the domains of child and family functioning targeted. Implications of the findings for policy and practice in responding to vulnerable families and children are discussed.

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Validation of treatment plan quality and dose calculation accuracy is essential for new radiotherapy techniques, including volumetric modulated arc therapy (VMAT). VMAT delivers intensity modulated radiotherapy treatments while simultaneously rotating the gantry, adding an additional level of complexity to both the dose calculation and delivery of VMAT treatments compared to static gantry IMRT. The purpose of this project was to compare two VMAT systems, Elekta VMAT and Varian RapidArc, to the current standard of care, IMRT, in terms of both treatment plan quality and dosimetric delivery accuracy using the Radiological Physics Center (RPC) head and neck (H&N) phantom. Clinically relevant treatment plans were created for the phantom using typical prescription and dose constraints for Elekta VMAT (planned with Pinnacle3 Smart Arc) and RapidArc and IMRT (both planned with Eclipse). The treatment plans were evaluated to determine if they were clinically comparable using several dosimetric criteria, including ability to meet dose objectives, hot spots, conformity index, and homogeneity index. The planned treatments were delivered to the phantom and absolute doses and relative dose distributions were measured with thermoluminescent dosimeters (TLDs) and radiochromic film, respectively. The measured and calculated doses of each treatment were compared to determine if they were clinically acceptable based upon RPC criteria of ±7% dose difference and 4 mm distance-to-agreement. Gamma analysis was used to assess dosimetric accuracy, as well. All treatment plans were able to meet the dosimetric objectives set by the RPC and had similar hot spots in the normal tissue. The Elekta VMAT plan was more homogenous but less conformal than the RapidArc and IMRT plans. When comparing the measured and calculated doses, all plans met the RPC ±7%/4 mm criteria. The percent of points passing the gamma analysis for each treatment delivery was acceptable. Treatment plan quality of the Elekta VMAT, RapidArc and IMRT treatments were comparable for consistent dose prescriptions and constraints. Additionally, the dosimetric accuracy of the Elekta VMAT and RapidArc treatments was verified to be within acceptable tolerances.