نتایج جستجو برای: vmat
تعداد نتایج: 1988 فیلتر نتایج به سال:
OBJECTIVES To explore the feasibility of multi-isocentric 4π volumetric-modulated arc therapy (MI4π-VMAT) for the complex targets of head and neck cancers. METHODS Twenty-five previously treated patients of HNC underwent re-planning to improve the dose distributions with either coplanar VMAT technique (CP-VMAT) or noncoplanar MI4π-VMAT plans. The latter, involving 3-6 noncoplanar arcs and 2-3...
BACKGROUND To compare dosimetric parameters of volumetric modulated arc therapy (VMAT) and non-coplanar intensity modulated radiotherapy (IMRT) for nasal cavity and paranasal sinus cancer with regard to the coverage of planning target volume (PTV) and the sparing of organs at risk (OAR). METHODS Ten patients with nasal cavity or paranasal sinus cancer were re-planned by VMAT (two-arc) plan an...
Consistency and reproducibility of the VMAT plan delivery using three independent validation methods
The complexity of VMAT delivery requires new methods and potentially new tools for the commissioning of these systems. It appears that great consideration is needed for quality assurance (QA) of these treatments since there are limited devices that are dedicated to the QA of rotational delivery. In this present study, we have evaluated the consistency and reproducibility of one prostate and one...
Amphetamines elevate extracellular dopamine, but the underlying mechanisms remain uncertain. Here we show in rodents that acute pharmacological inhibition of the vesicular monoamine transporter (VMAT) blocks amphetamine-induced locomotion and self-administration without impacting cocaine-induced behaviours. To study VMAT's role in mediating amphetamine action in dopamine neurons, we have used n...
Purpose: To retrospectively compare dosimetrically three dimensional field-in-field tangents (3D F-in-F), Intensity modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT) left breast irradiation plans. Materials Methods: A total of 30 patients were included in this study. All diagnosed with early–stage malignant neoplasm the prior to treatment. Patients contoured main PTV-Chest wall (P...
Purpose or Objective: Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are widely used in the treatment of advanced stage non-small cell lung cancer (NSCLC). These techniques deliver conformal dose distributions at the cost of increased target dose heterogeneity (particularly IMRT) and larger volumes of surrounding healthy tissues receiving low doses (par...
Volumetric-modulated arc therapy (VMAT) is an efficient form of radiotherapy used to deliver intensity-modulated radiotherapy beams. The aim of this study was to investigate the relative insensitivity of VMAT plan quality to gantry angle spacing (GS). Most previous VMAT planning and dosimetric work for GS resolution has been conducted for single arc VMAT. In this work, a quantitative comparison...
In this paper it is formally shown that the dynamic multileaf collimator (MLC) IMRT delivery technique remains valid if the MLC is supported on a 1D moving platform. It is also shown that, in such circumstances, it is always time preferable to deliver overlapping modulating fields as a single swept field rather than as separate fields. The most general formulism is presented and then related to...
This study evaluated the dosimetric difference between volumetric-modulated arc therapy (VMAT) and conventional fixed-field intensity-modulated radiotherapy (cIMRT) in whole-ventricular irradiation. Computed tomography simulation data for 13 patients were acquired to create plans for VMAT and cIMRT. In both plans, the same median dose (100% = 24 Gy) was prescribed to the planning target volume ...
PURPOSE To evaluate the dosimetric implications of using VMAT (Volume Modulated Arc Therapy) treatment planning techniques compared to traditional Arc therapy methods for patients undergoing SBRT (Stereotactic Body Radiation Therapy) for early-stage Non-Small Cell Lung Cancer (NSCLC). METHODS Ten NSCLC cancer patients are planned with both VMAT and Arc techniques. The SBRT treatment plans com...
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