نتایج جستجو برای: ptv margin

تعداد نتایج: 35795  

2016
Hosang Jin Vance P. Keeling Imad Ali Salahuddin Ahmad

Dosimetric consequences of positional shifts were studied using frameless Brainlab ExacTrac X-ray system for hypofractionated (3 or 5 fractions) intracranial stereo-tactic radiotherapy (SRT). SRT treatments of 17 patients with metastatic intracranial tumors using the stereotactic system were retrospectively investigated. The treatments were simulated in a treatment planning system by modifying ...

Journal: :Journal of cancer research and therapeutics 2008
Ashwini Budrukkar Debnarayan Dutta Dayanand Sharma Premnath Yadav Smitha Dantas Rakesh Jalali

AIMS AND OBJECTIVES To study the geometric uncertainties in the treatment and evaluate the adequacy of the margins employed for planning target volume (PTV) generation in the treatment of focal conformal radiotherapy (CRT) for patients with brain tumors treated with different head support systems. MATERIALS AND METHODS The study population included 11 patients with brain tumors who were to be...

2010
Chris Beltran Atmaram S. Pai Panandiker Matthew J. Krasin Thomas E. Merchant

The purpose was to quantify the setup margin for pediatric patients with neuro-blastoma using cone beam CT imaging (CBCT) and ultrasound localization. Ten patients, with a median age of 4.3 years (1.8 to 7.9) underwent daily pretreatment localization CBCT and every other day post-treatment CBCT to calculate interfractional and intrafraction movement. Localization was based on CBCT to treatment ...

2011
John H Heinzerling Ross Bland John C Mansour Roderich E Schwarz Ezequiel Ramirez Chuxiong Ding Ramzi Abdulrahman Thomas P Boike Timothy Solberg Robert D Timmerman Jeffrey J Meyer

BACKGROUND The retroperitoneal margin is a common site of positive surgical margins in patients with resectable pancreatic cancer. Preoperative margin-intensive therapy (MIT) involves delivery of a single high dose of ablative radiotherapy (30 Gy) focused on this surgically inaccessible margin, utilizing stereotactic techniques in an effort to reduce local failure following surgery. In this stu...

2010
Daniel Gomez Oren Cahlon James Mechalakos Nancy Lee

INTRODUCTION Intensity modulated radiation therapy (IMRT) has been incorporated at several institutions for early stage laryngeal cancer (T1/T2N0M0), but its utility is controversial. METHODS In three representative patients, multiple plans were generated: 1) Conventional 2D planning, with the posterior border placed at either the anterior aspect ("tight" plan) or the mid-vertebral body ("loo...

2015
Harumitsu Hashimoto Motoko Omura Kengo Matsui Yuki Mukai Hideyuki Hongo Wataru Yamakabe Kaori Saito Miwa Yoshida

TomoDirect (TD) is an intensity-modulated radiotherapy system that uses a fixed gantry angle instead of rotational beam delivery. Here, we investigated the effect of the multiple beam technique of TomoDirect on dose distribution compared with commonly-used tangential beams. We included 45 consecutive patients with right breast cancer who underwent postoperative radiotherapy in our institute in ...

Introduction: We aimed to dosimetrically compare three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) in terms of planning target volume (PTV) coverage, organ at risk (OAR) sparing, and conformity index (CI). Material and Methods: Planning data of 26 high grade glioma (HGG) patients were used. Prescrib...

2013
Wen-Jing Yin Ying Sun Feng Chi Jian-Lan Fang Rui Guo Xiao-Li Yu Yan-Ping Mao Zhen-Yu Qi Ying Guo Meng-Zhong Liu Jun Ma

BACKGROUND This prospective study was conducted to evaluate inter- and intra-fraction errors in nasopharyngeal carcinoma (NPC) patients undergoing volumetric modulated arc therapy (VMAT) using cone-beam computed tomography (CBCT) and to thus obtain planning target volume (PTV) margins to effectively guide treatment in the future. METHODS Fifteen NPC patients scheduled to undergo VMAT were pro...

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