objective(s): use of a positron emission tomography (pet)/single-photonemission computed tomography (spect) system facilitates the simultaneousacquisition of images with fluorine-18 fluorodeoxyglucose (18f-fdg) andtechnetium (99mtc)-tetrofosmin. however, 18f has a short half-life, and 511kev compton-scattered photons are detected in the 99mtc energy window.therefore, in this study, we aimed to ...

background:  this study presents patient specific and organ dose estimation in computed tomography (ct) imaging of thorax directly from patient ct image using monte carlo simulation.  patient's ct image is considered as the patient specific phantom and the best representative of patient physical index in order to calculate specific organ dose. materials and methods: egsnrc /beamnrc monte c...

Background: Radioiodine therapy has proven to be an effective method in the treatment of patients with differentiated thyroid carcinoma after thyroidectomy. The scope of this study is to describe a method to obtain the dose of organs using medical internal radiation dosimetry (MIRD) method. At the end, the results of MIRD calculations were compared with thermoluminescent dosimeter (TLD...

introduction: poor sensitivity and poor signal to noise ratio because of low injected thallium dose and presence of scattered photons are the main problems in using thallium in scintigraphic imaging of the heart. scattered photons are the main cause of degrading the contrast and resolution in spect imaging that result in error in quantification. thallium decay is very complicated and photons ar...

Introduction The use of cut-outs in electron applicators make changes on output, isodose, and percentage depth dose (PDD) curves. These changes and electron beam dose distribution in the form of three-dimensional (3D) can be measured by gel dosimeters. Materials and Methods Dosimetry was performed with and without a square shield (6×6 cm2 field). The energies were 4, 9, and 16 MeV and phantom w...

Background: Intensity modulated radiation therapy (IMRT) is an advanced method for delivery of three dimensional therapies, which provides optimal dose distribution with giving multiple nonuniform fluency to the patient. The complex dose distribution of IMRT should be checked to ensure that the accurate dose is delivered. Today, film dosimetry is a powerful tool for radiotherapy treatment Quali...

Defect engineering plays an important role in tailoring the electronic transport properties of van der Waals materials. Methods reported so far mainly rely on $e\phantom{\rule{0}{0ex}}x\phantom{\rule{0.333em}{0ex}}s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ defect type and concentration, hindering realization new types device functionalities associated with engine...

objective: radiochromic ebt3 film is a later generation of radiochromic films. the aim of this study is to compare ebt and ebt3 radiochromic films in radiotherapy fields of breast cancer. methods: a rando phantom was irradiated by a 6 mv siemens primus linac with medial and lateral fields of radiotherapy of breast cancer. dosimetry was performed in various points in the fields using ebt and ebt...

Introduction. The recently discovered acceleration of the universe [1, 2] indicates that its large-scale evolution is dominated by unknown dark energy which violates at least the strong energy condition, and perhaps also the weak energy condition, where it is known as phantom energy [3]. Such phantom energy is precisely what is needed to support traversable wormholes [4, 5, 6, 7, 8, 9]. This Le...