نتایج جستجو برای: treatment time absorbed dose
تعداد نتایج: 3277747 فیلتر نتایج به سال:
Intracavitary Brachytherapy is one of the most used methods for the treatment of the cervical-uterine cancer treatment, which is the main cause of cancer women death. This treatment consists in the insertion of low rate dose Cs sources into the patient. The most used system for the treatment dose planning is that of Manchester. This planning is based on sources, which are considered fixed durin...
introduction: average glandular dose calculation in mammography with mo-rh target-filter and dose calculation for different situations is accurate and fast. material and methods: in this research, first of all, x-ray spectra of a mo target bombarded by a 28 kev electron beam with and without a rh filter were calculated using the mcnp code. then, we used the sobol-wu parameters to write a fortra...
background: human activities such as mining enhance the radioactivity levels above normal background which can lead to an incremental increase in the radiation risk to the population. materials and methods: 20 tailing enriched soil samples collected around maiganga coal mine, gombe, northeast nigeria were assessed for their 226ra, 232th and 40k contents using hpge gamma-ray detector. results: t...
background: the presence of radionuclides in the soil, measures need to be taken to minimize the radiation dose to humans. it is mostly gamma-emitting radionuclides that contribute to the radiation dose in long term behavior of these radionuclides in soil may determine the extent to which such countermeasures need to be applied. materials and methods: the activity concentration of these radionu...
Introduction: Proton radiotherapy is the one of advanced teletherapy methods. The protons deposit their maximum energy in a position called Bragg peak. Therefore, for treatment of cancer, the tumor should be placed at the Bragg peak or SOBP. The scattered photons and neutrons is a challenge in proton radiotherapy. The aim of this study is calculation of absorbed dose from scatt...
background: absolute dosimetry of external beam radiotherapy is carried out by the use of ionization chambers. these chambers must be calibrated at a standard dosimetry laboratory before any use in clinical dosimetry. the secondary standard dosimetry laboratory of iran (ssdl) has the duty of calibrating the ionization chambers used in radiotherapy centers in iran. materials and methods: the pre...
Introduction: Internal radiation dosimetry is important from a radiation protection point of view and can help to optimize the radiation dose delivered to the workers, public, and patients. It has a rather simple protocol but needs a large amount of data. Therefore, it is difficult to do on a routine basis. The use of computer programs makes internal radiation dosimetry simpler...
introduction: clinical application of encapsulated radioactive brachytherapy sources has a major role in cancer treatment. in the present research, the effects of different tissue densities on the dose distribution of a 103pd brachytherapy source in a spherical phantom of 50 cm radius have been studied. material and methods: as is well known, absorbed dose in tissue depends to its density, but ...
Introduction: Gamma Knife is an instrument specially designed for treating brain disorders. In Gamma Knife, there are 201 narrow beams of cobalt-60 sources that intersect at an isocenter point to treat brain tumors. The tumor is placed at the isocenter and is treated by the emitted gamma rays. Therefore, there is a high dose at this point and a low dose is delivered to the normal tissue surroun...
determination of the total body absorbed dose consists of two parts: beta radiation absorbed dose and gamma radiation absorbed dose. the first part is generally determined by clinical data, while the second part has a parameter called absorbed ratio and is determined by computational methods. the monte-carlo computational methods have been shown to be the most suitable in determination of the a...
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