نتایج جستجو برای: megavoltage radiotherapy

تعداد نتایج: 62462  

2011
Winky Wing Ki Fung Vincent Wing Cheung Wu

The sharp dose gradients in intensity-modulated radiation therapy increase the treatment sensitivity to various interand intra-fractional uncertainties, in which a slight anatomical change may greatly alter the actual dose delivered. Image-guided radiotherapy refers to the use of advanced imaging techniques to precisely track and correct these patient-specific variations in routine treatment. I...

Journal: :Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 1998
A Nisbet D I Thwaites M E Sheridan

BACKGROUND AND PURPOSE A comprehensive dosimetry intercomparison has been carried out involving all the radiotherapy centres, all external beam modalities and every radiotherapy treatment unit in the Republic of Ireland. MATERIALS AND METHODS Reference point measurements were made for all megavoltage photon beams. Doses were also investigated in planned three-field distributions. One of these...

2015
Vikneswary Batumalai Alexandra Quinn Michael Jameson Geoff Delaney Lois Holloway

INTRODUCTION Correct target positioning is crucial for accurate dose delivery in breast radiotherapy resulting in utilisation of daily imaging. However, the radiation dose from daily imaging is associated with increased probability of secondary induced cancer. The aim of this study was to quantify doses associated with three imaging modalities and investigate the correlation of dose and varying...

2012
R. M. V. Silva D. N. Souza

This paper presents a model for the characterization and selection of beeswaxes for use as base substitute tissue for the manufacture of objects suitable for external radiotherapy using megavoltage photon beams. The model of characterization was divided into three distinct stages: 1) verification of aspects related to the origin of the beeswax, the bee species, the flora in the vicinity of the ...

Journal: :Communications physics 2021

Abstract Very high energy electron (VHEE) beams have been proposed as an alternative radiotherapy modality to megavoltage photons; they penetrate deeply without significant scattering in inhomogeneous tissue because of their relativistic inertia. However, the depth dose distribution a single, collimated VHEE beam is quasi-uniform, which can lead healthy being overexposed. This be largely overco...

Journal: :Physics in medicine and biology 2002
Larry E Antonuk

A review of electronic portal imaging devices (EPIDs) used in external beam, megavoltage radiation therapy is presented. The review consists of a brief introduction to the definition, role and clinical significance of portal imaging, along with a discussion of radiotherapy film systems and the motivations for EPIDs. This is followed by a summary of the challenges and constraints inherent to por...

Journal: :Asian Pacific journal of cancer prevention : APJCP 2013
Temsak Phungrassami Amporn Funsian Hutcha Sriplung

BACKGROUND To study the pattern of patient load, personnel and equipment resources from 30-years experience in Southern Thailand. MATERIALS AND METHODS This retrospective study collected secondary data from the Division of Therapeutic Radiology and Oncology and the Songklanagarind Hospital Tumor Registry database, Faculty of Medicine, Prince of Songkla University, during the period of 1982-20...

Journal: :iranian journal of medical physics 0
rezvan khaldari medical physics department, medical school, tabriz university of medical sciences, tabriz, iran asghar mesbahi medical physics department, medical school, tabriz university of medical sciences, tabriz, iran. umit kara suleyman demirel university

introduction: globally, the need for radiotherapy as a part of cancer management increases every year. thus, the shielding for megavoltage radiotherapy rooms is of great importance. materials and methods: in the present study, 14 types of developed high-density concrete with densities ranging from 2.45 to 5.11 were simulated by using monte carlo method. the linear attenuation coefficient and th...

Journal: :Australasian Physical & Engineering Sciences in Medicine 2015

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