نتایج جستجو برای: radiotherapy dose distribution

تعداد نتایج: 953798  

A.D. Esmaeeli, A.S. Monfared, D. Moslemi, M. Pouladian, S.R. Mahdavi,

Background: To reduce the dose to normal tissues surrounding the treated breast, a uniform magnetic field was used within a humanoid phantom in breast radiotherapy. Materials and Methods: Monte Carlo simulations were performed with GEANT4, irradiating humanoid phantoms in a magnetic field. To reconstruct phantoms, computed tomography (CT) data slices of four patients were used for the Monte Car...

C. Geng, C. Gong, D. Chen, D. Shu, H. Yu, S. Hang, X. Tang,

Background: Boron neutron capture therapy (BNCT) is a radiotherapy that combines biological targeting and high linear energy transfer. A potential therapeutic approach for non-small cell lung cancer (NSCLC) is considered. However, dose in lung tumor is not homogeneous, and it will reduce the effect of BNCT treatment. In order to improve the dose distribution of BNCT, the multi-field irradiation...

Objective: The aim of this study is to evaluate the effect of tissue composition on dose distribution in electron beam radiotherapy.Methods: A Siemens Primus linear accelerator and a phantom were simulated using MCNPX Monte Carlo code. In a homogeneous cylindrical phantom, six types of soft tissue and three types of tissue-equivalent materials were investigated. The tissues included muscle (ske...

2011
Volker Rudat Abdul Aziz Alaradi Adel Mohamed Khaled AI-Yahya Saleh Altuwaijri

BACKGROUND This study evaluates the dose distribution of reversed planned tangential beam intensity modulated radiotherapy (IMRT) compared to standard wedged tangential beam three-dimensionally planned conformal radiotherapy (3D-CRT) of the chest wall in unselected postmastectomy breast cancer patients METHODS For 20 unselected subsequent postmastectomy breast cancer patients tangential beam ...

Introduction: Globally, intensity-modulated radiation therapy (IMRT) is considered as highly precise and accurate method of radiotherapy planning. This technique amplifies spatial dose distribution conformity by modulating the intensity of radiation beams in each sub-volume. Additionally, it can reduces the dose to surrounding critical organs and deliver the planned dose to targets with the nom...

G. Yilmazer, M. Izmirli, M. Nart, T. Cakir, Z.A. Palabiyik,

Aims: It was aimed to investigate postoperative conformal radiotherapy planning that provides the best target volume and the least dose for critical organs in cancers of stomach. Methods: This study was conducted on the CT simulation images of thirty patients diagnosed with gastric cancer. Target volumes and the organs at risk were contoured. AP-PA reciprocal parallel field conventional plan an...

2012
Ni Xin‐ye Tang Xiao‐bin Geng Chang‐ran Chen Da

Because of their superior characteristics, carbonaceous materials, which are still at their early stage of development, have garnered significant interest. Because of their low atomic number, carbonaceous orthopedic implants possess radiation properties similar to biological tissues and, therefore, they are more suitable to patients in need of radiotherapy. The effects of stainless steel, titan...

M Hazbavi M J Tahmasebi Birgani, M Tahmasbi N Chegeni, S M Hoseini

Background: In radiotherapy, low-energy photon beams are better adapted to the treated volume, and the use of high-energy beams can reduce hot spots in the radiation therapy. Therefore, mixing low and high energies with different ratios can control the rate of hotspots, as well as the dose distribution of the target volume.Material and Methods: The percentage depth doses (PDDs) were calculated ...

2014
Yang‐Kyun Park Soyeon Park Hong‐Gyun Wu Siyong Kim

Dose painting radiotherapy is considered a promising radiotherapy technology that enables more targeted dose delivery to tumor rich regions while saving critical normal tissues. Obviously, dose painting planning would be more complicated and hard to be evaluated with current plan quality index systems that were developed under the paradigm of uniform dose prescription. In this study, we introdu...

Maryam Hazbavi, Marziyeh Tahmasbi Mohammad Javad Tahmasebi Birgani Nahid Chegeni

Introduction: Many studies have shown the effects of delivered dose distribution due to the incident photon energy on the tumor and healthy tissues. The ability to access the most appropriate radiation energy is essential to achieve the optimal treatment planning but there is a serious limitation in number of energies available on radiation therapy machines can restrict it. <s...

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