نتایج جستجو برای: percentage depth dose

تعداد نتایج: 592179  

آروندی, شعله, طهماسبی بیرگانی, محمد جواد, بهروز, محمد علی, طبری جویباری, راحله, طهماسبی, مرضیه,

Background and purpose: Electron beams are extensively used in superficial cancer therapy. Unlike photon therapy, percentage depth dose curves (PDD) do not specify a maximum point in high energy electron therapy and include a depth range. The aim of this study was to obtain PDD by an analytical formulation which can be helpful to acquire the size of treatment area and other treatment factors su...

2013
Mohamad Javad Tahmasebi Birgani Nahid Chegeni Shole Arvandi Sasan Razmjoo Ghalaee Mansoor Zabihzadeh Davood Khezerloo

Nowadays, in most radiotherapy departments, the commercial treatment planning systems (TPS) used to calculate dose distributions needs to be verified; therefore, quick, easy-to-use, and low-cost dose distribution algorithms are desirable to test and verify the performance of the TPS. In this paper, we put forth an analytical method to calculate the phantom scatter contribution and depth dose on...

2015
Rezvan Azimi Parham Alaei Emiliano Spezi Susanta K. Hui

Orthovoltage irradiators are routinely used to irradiate specimens and small animals in biological research. There are several reports on the characteristics of these units for small field irradiations. However, there is limited knowledge about use of these units for large fields, which are essential for emerging large-field irregular shape irradiations, namely total marrow irradiation used as ...

Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab-wooden dust (pine)-SP34 slab (SWS) heterogeneous phantom.  Materials and Methods: Th...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده زیست شناسی 1388

126 abstract: in this research we studied the effects of cyclic hydration and dehydration of cysts of artemia urmiana and artemia parthenogenetica on the hatching percentage, survival and growth. the experiment was carried out in 3 treatments (1-3 hydration/dehydration cycles) with 3 replicates for each treatment. later effects of cold preservation at -20°c during three time periods were ...

2013
M Mahdavi M KhademAbolfazli S-R-M Mahdavi Gh Ataei

BACKGROUND Radiation-sensitive polymer gels are among the most promising three-dimensional dose verification tools and tissue-like phantom developed to date. OBJECTIVE The aim of this study is an investigating of percentage depth dose enhancement within the gel medium with used of conformal distribution gold nanoparticle as contrast agents by high atomic number material. METHODS In this wor...

Journal: :iranian journal of radiation research 0
m.j. tahmasebi birgani medical physics department, jondi shapour university of medical sciences, ahwaz, iran m.a. behrooz medical physics department, jondi shapour university of medical sciences, ahwaz, iran h. shahbazian radiation therapy department, golestan hospital, jondi shapour university of medical science, ahwaz, iran a. shams medical physics department, jondi shapour university of medical sciences, ahwaz, iran

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 ...

ژورنال: سنجش و ایمنی پرتو 2015

With the development of science and technology in the medical field and need more than ever to accuracy and quality of treatment has been causer increase different radiotherapy methods. Almost the past two decade’s intraoperative radiation therapy (IORT) as one of the new techniques used to treat cancer patients. One of the problems with this method is obtaining accurate dosimetry, becaus...

Introduction: Irregular/blocked fields are routinely used in radiotherapy. The doses of these fields are usually calculated by means of equivalent square method that is inherently prone to uncertainty. On the other hand, Clarkson’s sector integration method is a dose calculation method which offers far better accuracy in dose calculation of irregular fields. The Scatter Air Ratio (SAR) of an in...

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