نتایج جستجو برای: phantom scatter factor

تعداد نتایج: 870740  

2017
Thorsten Heußer Philipp Mann Christopher M Rank Martin Schäfer Antonia Dimitrakopoulou-Strauss Heinz-Peter Schlemmer Boris A Hadaschik Klaus Kopka Peter Bachert Marc Kachelrieß Martin T Freitag

OBJECTIVES Combined positron emission tomography (PET) and magnetic resonance imaging (MRI) targeting the prostate-specific membrane antigen (PSMA) with a 68Ga-labelled PSMA-analog (68Ga-PSMA-11) is discussed as a promising diagnostic method for patients with suspicion or history of prostate cancer. One potential drawback of this method are severe photopenic (halo-) artifacts surrounding the bl...

Journal: :Technology in cancer research & treatment 2002
C A MacDonald W M Gibson W W Peppler

Polycapillary x-ray optics provide an innovative new way to control x-ray beams. Placing these optics after the object to be imaged provides very efficient rejection of Compton scatter, while allowing image magnification without loss of resolution, image demagnification, or image shaping to match with digital detectors. Measured scatter rejection optics had primary transmissions greater than 50...

Journal: :iranian journal of radiation research 0
e. raeisi department. of medical physics, tarbiat modares university, tehran, iran h. rajabi department. of medical physics, tarbiat modares university, tehran, iran s.m.r. aghamiri division of radiation medicine, shahid beheshti university, tehran, iran

abtract background: in nuclear medicine, phantoms are mainly used to evaluate the overall performance of the imaging systems and practically there is no phantom exclusively designed for the evaluation of the software performance.  in this study the hoffman brain phantom was used for quantitative evaluation of reconstruction techniques. the phantom is modified to acquire tomographic and planar i...

2015
J. H. Lee L. T. Chang A. C. Shiau C. W. Chen Y. J. Liao W. J. Li M. S. Lee S. M. Hsu

A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent do...

M. Amoui, M. Hosntalab, M.R. Teimoori Sichani, Sh. Akhlaghpoor,

Background: In this study, Quantitative 32P bremsstrahlung planar and SPECT imaging and consequent dose assessment were carried out as a comprehensive phantom study to define an appropriate method for accurate Dosimetry in clinical practice. Materials and Methods: CT, planar and SPECT bremsstrahlung images of Jaszczak phantom containing a known activity of 32P were acquired. In addition, Phanto...

Introduction: The Sc is an important parameter to monitor unit (MU) calculation in radiation therapy procedure. The aim of this study is to measurement and comparison of head scatter factor (Sc) for 9MV photon beam using the build-up cap and a columnar mini-phantom.   Materials and Methods: The measurements performed using a calibrated ion chamber (Scanditron...

Journal: :iranian journal of radiation research 0
a. takavar department of medical physics, tehran university of medical sciences,tehran, iran gh. shamsipour m. sohrabi m. eftekhari

background: in myocardial perfusion spect imaging, images are degraded by photon attenuation, the distance-dependent collimator, detector response and photons scatter. filters greatly affect quality of nuclear medicine images materials and methods: a phantom simulating heart left ventricle was built. about 1mci of 99mtc was injected into the phantom. images were taken from this phantom. some fi...

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 ...

E. Raeisi, H. Rajabi, S.M.R. Aghamiri,

ABTRACT Background: In nuclear medicine, phantoms are mainly used to evaluate the overall performance of the imaging systems and practically there is no phantom exclusively designed for the evaluation of the software performance.  In this study the Hoffman brain phantom was used for quantitative evaluation of reconstruction techniques. The phantom is modified to acquire t...

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