نتایج جستجو برای: dose optimization

تعداد نتایج: 624710  

Background:The most efficient application of ionizing radiation is serving medical purposes and using this radiation has caused people to learn that artificial sources of radiation exposure among these resources can be of highest exposure rate.  Objective: The present study is aimed at initially establishing a baseline for local-reference dose level in Mazandaran, Iran in 12 projections of the...

2012
Ramachandran Prabhakar Jim Cramb Christopher Gehrke Justin Anderson Judy Andrews

The aim of this study was to compare IMRT optimization in the CMS XiO radiotherapy treatment planning system, with and without segment weight optimization. Twenty-one prostate cancer patients were selected for this study. All patients were initially planned with step-and-shoot IMRT (S-IMRT). A new plan was then created for each patient by applying the segment weight optimization tool (SWO-IMRT)...

Journal: :Medical physics 2011
Ehsan Salari Chunhua Men H Edwin Romeijn

PURPOSE Traditionally, the tongue-and-groove effect due to the multileaf collimator architecture in intensity-modulated radiation therapy (IMRT) has typically been deferred to the leaf sequencing stage. The authors propose a new direct aperture optimization method for IMRT treatment planning that explicitly incorporates dose calculation inaccuracies due to the tongue-and-groove effect into the ...

2018
Ivaylo B Mihaylov Eric A Mellon Raphael Yechieli Lorraine Portelance

PURPOSE Inverse planning is trial-and-error iterative process. This work introduces a fully automated inverse optimization approach, where the treatment plan is closely tailored to the unique patient anatomy. The auto-optimization is applied to pancreatic stereotactic body radiotherapy (SBRT). MATERIALS AND METHODS The automation is based on stepwise reduction of dose-volume histograms (DVHs)...

2013
Mark K.H. Chan Dora L.W. Kwong Anthony Tong Eric Tam Sherry C.Y. Ng

Inverse optimization of robotic stereotactic lung radiotherapy is typically performed using relatively simple dose calculation algorithm on a single instance of breathing geometry. Variations of patient geometry and tissue density during respiration could reduce the dose accuracy of these 3D optimized plans. To quantify the potential benefits of direct four-dimensional (4D) optimization in robo...

Introduction: whole body bone scan is one of the most useful procedures of nuclear medicine. Accurate distribution of radiopharmaceutical is yielded by using SPECT-CT. There are concerns about the radiation dose of CT part. The present study aimed to evaluate the patients’ dose in bone nuclear medicine imaging. Methods and Materials: First of all, the dose report of CT console was calibrated u...

Journal: :iranian journal of fuzzy systems 2011
alireza fakharzadeh jahromi omolbanin bozorg hamidreza maleki mohamad amin mosleh-shirazi

although many methods exist for intensity modulated radiotherapy (imrt) fluence map optimization for crisp data, based on clinical practice, some of the involved parameters are fuzzy. in this paper, the best fluence maps for an imrt procedure were identifed as a solution of an optimization problem with a quadratic objective function, where the prescribed target dose vector was fuzzy. first, a d...

2003
Michael Lahanas Eduard Schreibmann Natasa Milickovic Dimos Baltas

We apply the NSGA-II algorithm and its controlled elitist version NSGA-IIc for the intensity modulated beam radiotherapy dose optimization problem. We compare the performance of the algorithms with objectives for which deterministic optimization methods provide global optimal solutions. The number of parameters to be optimized can be up to a few thousands and the number of objectives varies fro...

Journal: :Physics in medicine and biology 2017
S Mueller M K Fix A Joosten D Henzen D Frei W Volken R Kueng D M Aebersold M F M Stampanoni P Manser

The aim of this work is to develop and investigate an inverse treatment planning process (TPP) for mixed beam radiotherapy (MBRT) capable of performing simultaneous optimization of photon and electron apertures. A simulated annealing based direct aperture optimization (DAO) is implemented to perform simultaneous optimization of photon and electron apertures, both shaped with the photon multilea...

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