نتایج جستجو برای: radiation therapy
تعداد نتایج: 852472 فیلتر نتایج به سال:
introduction evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. materials and methods a system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...
esophageal cancer is one of the most common malignancies with a growing occurrence . it presently ranks ninth among the most frequent cancers in the world and the sixth leading cause of death from cancer . for a variety of reasons, the mainstream of patients with esophageal cancer is actually not suitable for esophagectomy. more than 50% have locally advanced unresectable or metastatic tumors a...
introduction intensity modulated radiation therapy (imrt) has made a significant progress in radiation therapy centers in recent years. in this method, each radiation beam is divided into many subfields that create a field with a modulated intensity. considering the complexity of this method, the quality control for imrt is a topic of interest for researchers. this article is about the various ...
background: intra-operative radiation therapy (iort) is the transfer of a single large radiation dose to the tumor bed during surgery with the final goal of improving regional tumor control. this study aimed to investigate the safety, effectiveness and economic evaluation of intra-operative radiation therapy. methods : the scientific literature was searched in the main biomedical databases (c...
Glioblastoma is most common and most aggressive cancer of brain. for treatment surgery is first selection and radiation therapy then chemotherapy. The median survival of Patients with GBM is less than a year after diagnosis. Glioblastoma is basically resistant to common cancer treatments. today to improve the response of patients to treatment, a number of strategies such as the use of radiation...
background: attenuation coefficient (μ) plays an important role in calculations of treatment planning systems, as well as determination of dose distributions in external beam therapy, dosimetry, protection, phantom materials and industry. so, its exact measurement or calculation is very important. the aim of this study was to evaluate the μ in different points in the water phantom analytically ...
introduction radiotherapy with small fields is used widely in newly developed techniques. additionally, dose calculation accuracy of treatment planning systems in small fields plays a crucial role in treatment outcome. in the present study, dose calculation accuracy of two commercial treatment planning systems was evaluated against monte carlo method. materials and methods siemens once or linea...
introduction today, there is a growing interest in the use of hadrontherapy as an advanced radiotherapy technique. hadrontherapy is considered a promising tool for cancer treatment, given its high radiobiological effectiveness and high accuracy of dose deposition due to the physical properties of hadrons. however, new radiation modalities of dose delivery and on-line beam monitoring play crucia...
Radiation damage depends on energy absorption, and is approximately proportional to the absorbed energy density in the tissue. In external radiation consideration with a certain energy flux, the amount of absorbed dose in each point of the tissue depends on the type of radiation, the radiation energy, the depth of the place of receipt, and the main components of the absorber environment. The ab...
background: the fundamental principles of internal targeted alpha therapy for cancer were established many decades ago.the high linear energy transfer (let) of alpha radiation to the targeted cancer cellscauses double strand breaks in dna. at the same time, the short range radiation spares adjacent normal tissues. this targeted approach complements conventional external beam radiotherapy and ch...
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