نتایج جستجو برای: conformal radiotherapy heterogeneity correction photon energies
تعداد نتایج: 453520 فیلتر نتایج به سال:
BACKGROUND AND PURPOSE One of the newer audit modalities operated by the International Atomic Energy Agency (IAEA) involves audits of treatment planning systems (TPS) in radiotherapy. The main focus of the audit is the dosimetry verification of the delivery of a radiation treatment plan for three-dimensional (3D) conformal radiotherapy using high energy photon beams. The audit has been carried ...
background: small photon fields are increasingly used in modern radiotherapy especially in intensity modulated radiation therapy (imrt) and stereotactic radiosurgery (srs) treatments. accurate beam profile and central axis depth doses measurements of such beams are complicated due to the electron disequilibrium. hence the ebt2 (external beam therapy) gafchromic film was used for dosimetry of sm...
The application of intensity-modulated radiation therapy (IMRT) has enabled the delivery of high doses to the target volume while sparing the surrounding normal tissues. The drawbacks of intensity modulation, as implemented using a computer controlled multileaf collimator (MLC), are the larger number of monitor units (MUs) and longer beam-on time as compared with conventional radiotherapy. Addi...
Photon dose calculation algorithms (such as the pencil beam and collapsed cone, CC) model the attenuation of a primary photon beam in media other than water, by using pathlength scaling based on the relative mass density of the media to water. In this study, we assess if differences in the electron density between the water and media, with different atomic composition, can influence the accurac...
Introduction and purpose: The aim of this study is introducing a new Mono-Isocentric Technique)MIT) for external radiotherapy of the chest wall in the mastectomy patients with 6MV photon beams and comparing this technique with the Dual-Isocentric Technique(DIT). Materials and methods: Data of 18 mastectomy patients having chest wall radiotherapy were used. The target tissue was divided into...
introduction: nowadays, considerable developments in the field of radiotherapy have been achieved. they include the advances made in the equipments and treatment planning techniques which require highly complex calculations. such achievements have made it possible to treat cancer patients not only with higher radiation dose but also with higher precision and con...
AIMS UK guidance was recently developed for the treatment of anal cancer using intensity-modulated radiotherapy (IMRT). We audited the current use of radiotherapy in UK cancer centres for the treatment of anal cancer against such guidance. We describe the acute toxicity of IMRT in comparison with patient population in the audit treated with two-phase conformal radiotherapy and the previous publ...
background: to compare the cosmetic results of whole breast radiotherapy between cobalt 60 and photon 9megavolt in patients underwent breast conserving surgery. methods: the patients with breast saving surgery who were treated by whole breast radiotherapy with either cobalt 60 or photon 9mv between 2001-2006 in sayed-al-shohada hospital entered the study. the cosmetic results were evaluated by ...
To achieve a good clinical outcome in radiotherapy treatment, a certain accuracy in the dose delivered to the patient is required. Therefore, it is necessary to keep the uncertainty in each of the steps of the process inside some acceptable values, which implies a global uncertainty as low as possible. This work is focused on the uncertainty evaluation of absorbed dose to water in the routine c...
AIMS AND BACKGROUND Radiotherapy represents one of the basic therapeutic methods in treatment of localized carcinoma of the prostate. Optimal irradiation dose is the cornerstone of a successful treatment. Along with local control of the disease and overall survival of the patient, possible acute and long-term side effects need to be monitored very closely. METHODS A non-randomized prospective...
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