نتایج جستجو برای: dose profiles

تعداد نتایج: 457822  

2014
Daniel Scandurra Catherine E. Lawford

This work develops a technique for kilovoltage cone-beam CT (CBCT) dosimetry that incorporates both point dose and integral dose in the form of dose length product, and uses readily available radiotherapy equipment. The dose from imaging protocols for a range of imaging parameters and treatment sites was evaluated. Conventional CT dosimetry using 100 mm long pencil chambers has been shown to be...

Journal: :iranian journal of radiation research 0
d. balakrishnan department of physics, the cochin college, kochi-2, kerala, india j.p. abraham department of physics, the cochin college, kochi-2, kerala, india a.g. umadevi department of chemistry, nss college, ottapalam, palakkad, kerala, india a. sunil department of physics, fatima mata national college, kollam, kerala, india p.j. jojo department of physics, fatima mata national college, kollam, kerala, india s. ben byju department of physics, fatima mata national college, kollam, kerala, india

background: natural background radiation of a particular region is one of the distinctive factors defining the status of environment. eloor island is an industrial area in ernakulum district of the state of kerala, india. the indoor and outdoor gamma level measurements have been carried out for the region for evaluating the annual effective dose to the population residing in this area. material...

Background: In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness.Methods: In this study, we used Monte Carlo method-based Geant4 toolkit to s...

Journal: :iranian journal of radiation research 0
m. mohammadi department of medical physics, royal adelaide hospital. adelaide, sa 5000, australia e. bezak

abstractbackground: although electronic portal imaging devices (epids) have originally developed for positioning verification, they can also be used for dosimetric purposes. in the current work, the dose response of minimum detectable thickness of a scanning liquid filled ion chamber epid, slic-epid, and the variation of transmitted dose with the shift of inhomogeneity inside of phantom was als...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1372

خطرات پره اکلامپسی و متعاقب آن اکلامپسی به خوبی مشخص می باشد. آسپرین low-dose با کاهش انتخابی ترومبوکسان a2 سبب غلبه پروستاسیکلین شده و به این طریق از پره اکلامپسی و عوارض آن جلوگیری می نماید. در این مطالعه 150 خانم حامله در معرض پره اکلامپسی به طور رندوم به دو گروه دریافت کننده آسپرین (60 نفر) و دریافت کننده آسپرین (90 نفر) تقسیم شدند. پراکلامپسی فقط در 2 نفر از گروه آسپرینی دیده شد(3/3

2013
N. Chegeni M. J. Tahmasebi Birgani

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 ...

Journal: :Medical physics 2005
S Steciw B Warkentin S Rathee B G Fallone

A three-dimensional (3D) intensity-modulated radiotherapy (IMRT) pretreatment verification procedure has been developed based on the measurement of two-dimensional (2D) primary fluence profiles using an amorphous silicon flat-panel electronic portal imaging device (EPID). As described in our previous work, fluence profiles are extracted from EPID images by deconvolution with kernels that repres...

Journal: :Physics in medicine and biology 2006
Oleg N Vassiliev Uwe Titt Falk Pönisch Stephen F Kry Radhe Mohan Michael T Gillin

Basic dosimetric properties of 6 MV and 18 MV photon beams from a Varian Clinac 21EX accelerator operating without the flattening filter have been measured. These include dose rate data, depth dose dependencies and lateral profiles in a water phantom, total scatter factors and transmission factors of a multileaf collimator. The data are reviewed and compared with measurements for the flattened ...

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...

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