نتایج جستجو برای: Buildup bolus

تعداد نتایج: 15646  

Hamid Reza Baghani, Seyed Hamid Zoljalali Moghaddam Seyed Rabi Mahdavi

Introduction: The received dose to the surface of tumor bed is one of the main issues in beast intraopeative radiotherapy (IORT). Totally, the administered dose to the surface is usually lower than that of radiotherapy reference point (distal end of tumor bed). Employing a buildup bolus can effectively increase the surface dose and therefore, eliminate such created cold points ...

2003
Eric E. Klein Jacqueline Esthappan Zuofeng Li

Understanding head scatter characteristics of photon beams is vital to properly commission treatment planning (TP) algorithms. Simultaneously, having definitive surface and buildup region dosimetry is important to optimize bolus. The Elekta Precise linacs have unique beam flattening filter configurations for each photon beam (6, 10, and 18 MV) in terms of material and location. We performed a c...

2017
Molham M. Eyadeh Marcin Wierzbicki Kevin R. Diamond

In external beam radiation therapy (EBRT), skin dose measurement is important to evaluate dose coverage of superficial target volumes. Treatment planning systems (TPSs) are often inaccurate in this region of the patient, so in vivo measurements are necessary for skin surface dose estimation. In this work, superficial dose distributions were measured using radiochromic translucent poly(vinyl alc...

2014
Mark J. Ashburner Samuel Tudor

When the planning target volume (PTV), extends close to or beyond the skin, inverse-planned intensity-modulated radiotherapy can boost the fluence from tan- gential angles to superficial parts of the PTV due to the buildup effect. This can result in significant regions of high dose upon a small movement in the patient's position. We analyzed different methods of reducing this effect in the Tomo...

2011
Paizlee T. Sieli Eldin Jašarevic´ Denise A. Warzak Jiude Mao Mark R. Ellersieck Chunyang Liao Kurunthachalam Kannan Séverine H. Collet Pierre-Louis Toutain Frederick S. vom Saal Cheryl S. Rosenfeld

BACKGROUND Bisphenol A (BPA) is a widely produced endocrine-disrupting chemical. Diet is a primary route of exposure, but internal exposure (serum concentrations) in animals and humans has been measured only after single oral bolus administration. OBJECTIVE We compared serum concentrations of BPA over a 24-hr period after oral bolus administration or ad libitum feeding in mice and assessed fo...

Journal: :Oncology 2015
Yuenan Wang Janelle Park

PURPOSE: A wide variation in the use of bolus has been observed in postmastectomy radiotherapy (PMRT), which affects dose delivery to skin and may have an impact on locoregional recurrence. However, even treatment planning systems (TPSs) with advanced algorithms do not provide accurate dosimetry in the buildup region. This study aims to perform in vivo measurements of the chest wall (CW) skin d...

Introduction: The postmastectomy radiotherapy uses bolus to improve the coverage close to the skin; however, it needs to be removed in case of severe skin toxicity. This study investigated the effect of bolus parameters (i.e., frequency and thickness) for the superposition algorithm on skin dose in postmastectomy three-dimensional conformal radiotherapy (3D-CRT). <str...

D. Matias, K. Jezierska, M. Boehlke, M. El Fray, M. Lewocki, M. Lukowiak, M. Piątek- Hnat, W. Kot, W. Podraza,

Background: This study describes the possibility of implementing three-dimensional printing technology to create a precise construction of a planned bolus, based on computed tomography information stored in the Digital Imaging and Communications in Medicine (DICOM) format file. Materials and Methods: &nbsp;To create the bolus with a 3D printer, we converted data in the DICOM format to the s...

ژورنال: سنجش و ایمنی پرتو 2016

The purpose of this study is to select the best place for the detector towards shield and the gamma source which have the least flux buildup factor of the photon. In this research, the flux buildup factor of gamma rays was calculated by using of MCNP-4C code for cylindrical sources 137Cs, 60Co, 16N coaxial shields made up of aluminum, iron and lead with a constant thickness 1.55 cm in detec...

Journal: :iranian journal of radiation research 0
m. lukowiak department of medical physics, west pomeranian oncology center, szczecin, poland m. boehlke department of medical physics, west pomeranian oncology center, szczecin, poland m. lewocki department of medical physics, west pomeranian oncology center, szczecin, poland w. kot department of medical physics, west pomeranian oncology center, szczecin, poland d. matias copernicus sp. zo.o., szczecin, poland m. piątek- hnat institute of polymers, department of biomaterials and microbiological technology, west pomeranian university of technology, szczecin, poland m. el fray

background: this study describes the possibility of implementing three-dimensional printing technology to create a precise construction of a planned bolus, based on computed tomography information stored in the digital imaging and communications in medicine (dicom) format file. materials and methods:  to create the bolus with a 3d printer, we converted data in the dicom format to the stereolith...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید