نتایج جستجو برای: gated vmat

تعداد نتایج: 32066  

2016
R. Wijsman F. Dankers E.G.C. Troost A. L. Hoffmann J. Bussink

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...

2017
Ghulam Murtaza Stefania Cora Ehsan Ullah Khan

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...

2009
S Webb D McQuaid

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...

Journal: :Medical dosimetry : official journal of the American Association of Medical Dosimetrists 2013
Katsuyuki Sakanaka Takashi Mizowaki Sayaka Sato Kengo Ogura Masahiro Hiraoka

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 ...

Journal: :Medical physics 2012
T Neicu P Chan V Valakh M Bizhan C Miyamoto S Li

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...

2014
Shogo Hatanaka Seiichi Tamaki Haruna Endo Norifumi Mizuno Naoki Nakamura

Volumetric-modulated arc therapy (VMAT) is a widespread intensity-modulated radiation therapy (IMRT) method, however, VMAT requires adaptation of the radiation treatment planning system (RTPS) and linear accelerator (linac); these upgrades are quite expensive. The Smart Arc of Pinnacle(3) (Philips), which is the software used in VMAT calculations, can select constant dose rate (CDR) mode. This ...

2014
Geoffrey P Nichols Jonas D Fontenot John P Gibbons Mary Ella Sanders

PURPOSE To examine the feasibility of volumetric modulated arc therapy (VMAT) for post mastectomy radiotherapy (PMRT). METHODS AND MATERIALS Fifteen PMRT patients previously treated at our clinic with helical tomotherapy (HT) were identified for the study. Planning target volumes (PTV) included the chest wall and regional lymph nodes. A systematic approach to constructing VMAT that met the cl...

Journal: :Medical physics 2012
Y Song P Zhang J Li C Burman M Chan

PURPOSE VMAT involves multi-parameter modulations, thus presenting multi-dimensional challenges. Here, we present a viable approach to VMAT patient specific QA using EPID-based dosimetry for spine VMAT SRS casesMethods: Our spine VMAT SRS plans consisted of two full arcs and were optimized with 6 MV photons for a Varian Trilogy LINAC. The QA plans were computed by resetting all control points t...

2015
Rui Guo Ling-Long Tang Yan-Ping Mao Guan-Qun Zhou Zhen-Yu Qi Li-Zhi Liu Ai-Hua Lin Meng-Zhong Liu Jun Ma Ying Sun Bart O. Williams

BACKGROUND To investigate the clinical efficacy and treatment toxicity of volume-modulated arc therapy (VMAT) for nasopharyngeal carcinoma (NPC). MATERIAL AND METHODS 205 VMAT-treated NPC patients from our cancer center were prospectively entrolled. All patients received 68-70 Gy irradiation based on the planning target volume of the primary gross tumor volume. Acute and late toxicities were ...

2012
Keiichi Nakagawa Satoshi Kida Akihiro Haga Yoshitaka Masutani Hideomi Yamashita Tsuyoshi Onoe Toshikazu Imae Kenichiro Tanaka Kuni Ohtomo Kiyoshi Yoda

We have proposed four dimensional (4D) digitally reconstructed radiography (DRR) for verifying a lung tumor position during volumetric modulated arc therapy (VMAT). An internal target volume (ITV) was defined based on two clinical target volumes (CTVs) delineated on maximum exhalation and maximum inhalation images acquired by 4D planning computed tomography (CT). A planning target volume (PTV) ...

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