نتایج جستجو برای: dosimetric audit absolute photon dose linacs

تعداد نتایج: 491847  

2017
Hoon Sik Choi Guang Sub Jo Jong Pyo Chae Sang Bong Lee Chul Hang Kim Bae Kwon Jeong Hojin Jeong Yun Hee Lee In Bong Ha Ki Mun Kang Jin Ho Song

We evaluated the changes in the dose distribution of radiation during volumetric arc radiotherapy (VMAT), to determine the right time for adaptive replanning in prostate cancer patients with progressive weight (WT) changes. Five prostate cancer patients treated with VMAT were selected for dosimetric analysis. On the original computed tomography images, nine artificial body contours were created...

2014
Hilde Van Parijs Truus Reynders Karina Heuninckx Dirk Verellen Guy Storme Mark De Ridder

BACKGROUND Breast conserving surgery followed by whole breast irradiation is widely accepted as standard of care for early breast cancer. Addition of a boost dose to the initial tumor area further reduces local recurrences. We investigated the dosimetric benefits of a simultaneously integrated boost (SIB) compared to a sequential boost to hypofractionate the boost volume, while maintaining norm...

2012
Rebecca M Howell Annelise Giebeler Wendi Koontz-Raisig Anita Mahajan Carol J Etzel Anthony M D’Amelio Kenneth L Homann Wayne D Newhauser

BACKGROUND For many decades, the standard of care radiotherapy regimen for medulloblastoma has been photon (megavoltage x-rays) craniospinal irradiation (CSI). The late effects associated with CSI are well-documented in the literature and are in-part attributed to unwanted dose to healthy tissue. Recently, there is growing interest in using proton therapy for CSI in pediatric and adolescent pat...

2016
Ravindra Shende Gourav Gupta Ganesh Patel Senthil Kumar

Motive of the study is to present quantitative and qualitative analysis and comparison of beam data measurement with FF (flattening filter) and FFF (flattening filter free) beam in a Varian TrueBeamTM Medical Linear Accelerator. Critique of beam characterization and evolution of dosimetric properties for 6 MV, 10 MV, 15 MV FF beam and 6 MVFFF, 10 MVFFF FFF beam has been carried out. We performe...

2007
Gareth J Webster Carl G Rowbottom Ranald I Mackay

Intensity-modulated radiotherapy (IMRT) for complex sites such as tumors of the head and neck requires a level of accuracy in dose calculation beyond that currently used for conformal treatment planning. Recent advances in treatment planning systems have aimed to improve the dose calculation accuracy by improving the modeling of machine characteristics such as interleaf leakage, tongue and groo...

2014
Teiji Nishio Hiroki Shirato Masayori Ishikawa Yuki Miyabe Satoshi Kito Yuichirou Narita Rikiya Onimaru Satoshi Ishikura Yoshinori Ito Masahiro Hiraoka

A domestic multicenter phase I study of stereotactic body radiotherapy (SBRT) for T2N0M0 non-small cell lung cancer in inoperable patients or elderly patients who refused surgery was initiated as the Japan Clinical Oncology Group trial (JCOG0702) in Japan. Prior to the clinical study, the accuracy of dose calculation in radiation treatment-planning systems was surveyed in participating institut...

2005
E. B. PODGORSAK

Since the inception of radiotherapy soon after the discovery of X rays by Roentgen in 1895, the technology of X ray production has first been aimed towards ever higher photon and electron beam energies and intensities, and more recently towards computerization and intensity modulated beam delivery. During the first 50 years of radiotherapy the technological progress was relatively slow and main...

Background: External beam radiation therapy is often administered to patients implanted with silicone gel breast prosthesis. The aim of this study was to investigate the influence of silicone gel breast prosthesis on photon dose distributions. In the event of recurrence, the oncologist may be forced to irradiate through the prosthetic device. To quantify the dose enhancement or reduction below ...

Journal: :BioMed research international 2016
Ying Zhang Yuanming Feng Xin Ming Jun Deng

A novel treatment modality termed energy modulated photon radiotherapy (EMXRT) was investigated. The first step of EMXRT was to determine beam energy for each gantry angle/anatomy configuration from a pool of photon energy beams (2 to 10 MV) with a newly developed energy selector. An inverse planning system using gradient search algorithm was then employed to optimize photon beam intensity of v...

Journal: :Physics in medicine and biology 2006
Oleg N Vassiliev Uwe Titt Falk Pönisch Stephen F Kry Radhe Mohan Michael T Gillin

Basic dosimetric properties of 6 MV and 18 MV photon beams from a Varian Clinac 21EX accelerator operating without the flattening filter have been measured. These include dose rate data, depth dose dependencies and lateral profiles in a water phantom, total scatter factors and transmission factors of a multileaf collimator. The data are reviewed and compared with measurements for the flattened ...

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