نتایج جستجو برای: mri dosimetry

تعداد نتایج: 113785  

Journal: :iranian journal of radiation research 0
sh. akhlaghpoor dr. sh. akhlaghpoor, novin medical radiation institute, p.o.box: 14665/599, tehran, iran; fax:(98) 218086782 m.h. zahmatkesh h. pourbeigi

background: since 1984 mri gel dosimetry has been introduced as a potential technique for 3d dosimetry. most of the studies have measured r1 (1/t1) or r2 (1/t2) properties of the gel depending on the gel type. we have studied image intensity change in the fricke gel by different mri protocols. materials and methods: gel dosimeters contain 0.4 mm ferrous sulphate, 1 mm nacl, 50 mm h2so4 and 1% b...

Journal: :iranian journal of medical physics 0
hossein hasani m.sc. student in medical radiation engineering, science and research branch, islamic azad university, tehran, iran hasan nedaie assistant professor, radiotherapy and oncology dept., tehran university of medical sciences, cancer research center, center institute, tehran, iran mohammad hasan zahmatkesh associate professor, medical physics dept., novin medical radiation institute, tehran, iran mahmood allahverdi associate professor, medical physics dept., tehran university of medical sciences, tehran, iran saeid bagheri m.sc. of medical physics, novin medical radiation institute, shahid beheshti university, tehran, iran sajad mirzaie m.sc. student in medical radiation engineering, science and research branch, islamic azad university, tehran, iran

introduction: in radiotherapy, methods of treatment planning are becoming increasingly more complicated. this requires verification of the doses delivered to increasingly smaller and more precise regions. radiotherapy techniques are continuously employing smaller and smaller field sizes to deliver tighter radiation doses with higher therapeutic ratios, generating interest among researchers to p...

Journal: :iranian journal of medical physics 0
mohammad taghi bahreyni toossi professor, medical physics research center, faculty of medicine, mashhad university of medical sciences, mashhad, iran ghorban safaeian m.sc., in medical physics, mashhad university of medical sciences, mashhad, iran mohammad hosein bahreyni toossi professor, medical physics research center, faculty of medicine, mashhad university of medical sciences, mashhad, iran shahram baiani m.sc., in medical engineering, medical physics research center, faculty of medicine, mashhad university of medical sciences, mashhad, iran

introduction: the purpose of this work was to study the ability of mri normoxic polymer gel dosimetry for evaluating the dose distribution in hdr brachytherapy of esophagial cancer at imam reza brachytherapy center (mashhad, iran). materials and methods: initially, 2liters of normoxic gel (magic) was fabricated and then poured into 12 calibration test tubes and placed in a perspex walled phanto...

Ghorban Safaeian Mohammad Hosein Bahreyni Toossi Mohammad Taghi Bahreyni Toossi, Shahram Baiani

Introduction: The purpose of this work was to study the ability of MRI normoxic polymer gel dosimetry for evaluating the dose distribution in HDR brachytherapy of esophagial cancer at Imam Reza brachytherapy center (Mashhad, Iran). Materials and Methods: Initially, 2liters of normoxic gel (MAGIC) was fabricated and then poured into 12 calibration test tubes and placed in a perspex walled phanto...

H. Pourbeigi, M.H. Zahmatkesh, Sh. Akhlaghpoor,

Background: Since 1984 MRI gel dosimetry has been introduced as a potential technique for 3D dosimetry. Most of the studies have measured R1 (1/T1) or R2 (1/T2) properties of the gel depending on the gel type. We have studied image intensity change in the Fricke gel by different MRI protocols. Materials and Methods: Gel Dosimeters contain 0.4 mM ferrous sulphate, 1 mM NaCl, 50 mM H2SO4 and 1% b...

Journal: :iranian journal of radiation research 0
m. gholami department of medical physics and medical engineering, school of medicine, isfahan university of medical sciences, isfahan, iran d. shahbazi-gahrouei department of medical physics and medical engineering, school of medicine, isfahan university of medical sciences, isfahan, iran t. allahverdi pourfallah department of biophysics and biochemistry, school of medicine, mazandaran university of medical sciences, sari, iran

background: the human body contains of different tissues and cavities with different physical and radiological properties. most important among these are tissues and cavities that are radiologically different from water, including lungs, sinuses and bones. gel dosimetry provides a unique feature to display dose distributions occurring in clinical radiation therapy in three dimensions. materials...

Journal: :iranian journal of medical physics 0
m. sedaghat ph.d. student in medical physics, university of sherbrooke, canada. m.h zahmatkesh assistant professor, novin medical radiation institute, tehran, iran. r. jaberi m.sc. in medical physics, cancer institute, imam hospital, tums, tehran, iran. sh. akhalghpoor assistant professor, faculty of medicine, tums & novin medical radiation institute, tehran, iran. m. allahverdi assistant professor, dept. of medical physics, faculty of medicine, tums & cancer institute of imam hospital, tehran, iran.

introduction: despite the fact that the clinical implementation of polymer gel dosimetry has been facilitated after the introduction of normoxic gels, there are still complications in its clinical routine use that are under investigation. in the current work, the feasibility of using a normoxic polymer gel dosimeter named magica has been investigated for use in our clinical brachytherapy applic...

Journal: :iranian journal of medical physics 0
bakhtiar azadbakht instructor, medical radiation engineering dept, faculty of engineering, borujerd islamic azad university, borujerd, iran. *, mohammad hassan zahmatkesh associate professor, shahid beheshti university, evin, tehran, iran kamal haddad associate professor, nuclear engineering dept, faculty of engineering, shiraz university, shiraz, iran. saeid bagheri m.sc. in medical physics, shahid beheshti university, tehran, iran

introduction: the pagat polymer gel dosimeter melts at 30 ˚c and even at room temperature during the summer, so it needs to be kept in a cool place such as a refrigerator. to increase the stability of the pagat gel, different amounts of agarose were added to the pagat gel composition and the pagata gel was manufactured. material and methods: the pagata gel vials were irradiated using a co-60 ma...

Journal: :Physics in medicine and biology 2006
M E Miquel K S Rhode P L Acher N D Macdougall J Blackall R P Gaston S Hegde S L Morris R Beaney C Deehan R Popert S F Keevil

Post-implantation dosimetry is an important element of permanent prostate brachytherapy. This process relies on accurate localization of implanted seeds relative to the surrounding organs. Localization is commonly achieved using CT images, which provide suboptimal prostate delineation. On MR images, conversely, prostate visualization is excellent but seed localization is imprecise due to distor...

Introduction: According to the literature, optical coherence tomography (OCT) can be used measure radiation absorbed dose. This study was carried out to design a computed tomography system for the calculation of absorbed dose and optimization of dose delivery in radiotherapy using gel dosimeters. Material and Methods: An advanced charge-coupled device based OCT system was developed in laborator...

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