Publications by authors named "Navid Ayoobian"

5 Publications

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The effect of gamma irradiation on the properties of cucumber.

J Food Sci Technol 2017 Dec 24;54(13):4277-4283. Epub 2017 Oct 24.

Department of Nuclear Engineering, Faculty of New Sciences and Technologies, University of Isfahan, Esfahān, Iran.

In this study, the effect of gamma irradiation on the shelf life and properties of cucumber was investigated. These properties include weight reduction, fruit density, juice, tissue firmness, total soluble solids (TSS), total titratable acidity, chlorophyll and vitamin C, pH, marketability, flavor, frostbite and fungal effects. For this purpose, cucumbers were irradiated with dose of 2, 2.5 and 3 kGy. The exposure time was calculated by MCNP4C; the Monte Carlo particle transport code. Three types of fungi (-, - and olive-), were used to infect some samples. The chlorophyll and vitamin C preservation abilities were increased to about 3 and 1.4 times, respectively with irradiation treatment. Also, the shelf life was increased about 1 week, while chilling injuries is decreased. Samples' resistance to the fungal growth was evident and the process of fungal growth on the irradiated samples was delayed up to 1 week. The best properties were obtained at the irradiation dose of 2 kGy since it had less effect on flavor, TSS and tissue firmness.
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http://dx.doi.org/10.1007/s13197-017-2899-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5686008PMC
December 2017

Erratum to: Monte Carlo dosimetry of the IRAsource high dose rate Ir brachytherapy source.

Australas Phys Eng Sci Med 2016 Jun 26;39(2):591. Epub 2016 Apr 26.

Nuclear Science Research School, Nuclear Science and Technology Research Institute NSTRI, Tehran, Iran.

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http://dx.doi.org/10.1007/s13246-016-0444-zDOI Listing
June 2016

Gafchromic film dosimetry of a new HDR 192Ir brachytherapy source.

J Appl Clin Med Phys 2016 03 8;17(2):194-205. Epub 2016 Mar 8.

University of Isfahan.

High-dose-rate (HDR) brachytherapy is a popular modality for treating cancers of the prostate, cervix, endometrium, breast, skin, bronchus, esophagus, and head and neck as well as soft-tissue sarcomas. Because of different source designs and licensing issues, there is a need for specific dosimetry dataset for each HDR source model. The main objective of the present work is to measure 2D relative dose distribution around a new prototype 192Ir source, referred to as IRAsource-HDR, in PMMA phantom in the framework of AAPM TG-43 and TG-55 recommendations for radial distances of 0.5cm to 4 cm. Radiochromic films (RCFs) Gafchromic EBT and HD-810 were used for measurements. The dose rate constant, Λ, of the source was determined to be 1.084± 4.6%, 1.129 ± 4.4%, and 1.112 ± 0.8% cGyh-1U-1 using EBT RCF, HD-810 RCF, and Monte Carlo (MC) simulation, respectively. The results obtained in this study are in good agreement with previously published data for HDR interstitial 192Ir-HDR sources with a maximum discrepancy of ± 4.5%. An acceptable agreement (within ± 2%) between MC calculations and RCFs measurements showed that HD-810 RCF dosimetry is as good as EBT RCF, within HDR brachytherapy, and justifies the use of specific data for this new source. These data could be used as a benchmark for dose calculations in the conventional brachytherapy treatment planning systems.
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http://dx.doi.org/10.1120/jacmp.v17i2.6005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5874862PMC
March 2016

Monte Carlo dosimetry of the IRAsource high dose rate (192)Ir brachytherapy source.

Australas Phys Eng Sci Med 2016 Jun 23;39(2):413-22. Epub 2016 Feb 23.

Nuclear Science Research School, Nuclear Science and Technology Research Institute NSTRI, Tehran, Iran.

High-dose-rate (HDR) brachytherapy is a common method for cancer treatment in clinical brachytherapy. Because of the different source designs, there is a need for specific dosimetry data set for each HDR model. The purpose of this study is to obtain detailed dose rate distributions in water phantom for a first prototype HDR (192)Ir brachytherapy source model, IRAsource, and compare with the other published works. In this study, Monte Carlo N-particle (MCNP version 4C) code was used to simulate the dose rate distributions around the HDR source. A full set of dosimetry parameters reported by the American Association of Physicists in Medicine Task Group No. 43U1 was evaluated. Also, the absorbed dose rate distributions in water, were obtained in an along-away look-up table. The dose rate constant, Λ, of the IRAsource was evaluated to be equal to 1.112 ± 0.005 cGy h(-1) U(-1). The results of dosimetry parameters are presented in tabulated and graphical formats and compared with those reported from other commercially available HDR (192)Ir sources, which are in good agreement. This justifies the use of specific data sets for this new source. The results obtained in this study can be used as input data in the conventional treatment planning systems.
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http://dx.doi.org/10.1007/s13246-016-0429-yDOI Listing
June 2016

Dosimetry parameters calculation of two commercial iodine brachytherapy sources using SMARTEPANTS with EPDL97 library.

J Cancer Res Ther 2012 Oct-Dec;8(4):610-8

Department of Nuclear Engineering, College of Mechanical Engineering, Shiraz University, Shiraz, Iran.

Aim: Simulating Many Accumulative Rutherford Trajectories Electron Photon and Neutral Transport Solver (SMARTEPANTS) is a discrete ordinates S N Boltzmann/Spencer-Lewis solver that was developed during 1988-1993 by William Filippone and his students. The code calculates particle fluxes, leakage currents as well as energy and charge deposition for coupled electron/photon in x-y-z geometries both in forward and in adjoin modes. Originally, SMARTEPANTS was designed to utilize CEPXS cross-section library for shielding calculation in satellite electronics. The aim of this study was to adapt SMARTEPANTS to use a new photon cross-section library from Evaluated Photon Data Library, 1997 version (EPDL97) for intravascular brachytherapy (125)Isimulations.

Materials And Methods: A MATLAB (MathworkNatick, Massachusetts) program was written to generate an updated multigroup-Legendre cross-section from EPDL97. The new library was confirmed by simulating intravascular brachytherapy Best® Model 2301 and Intersource (125)I dosimetry parameters using SMARTEPANTS with different energy groups (g), Legendre moments (L) and discrete ordinate orders (S).

Results: The dosimetry parameters for these sources were tabulated and compared with the data given by AAPM TG-43 and other reports. The computation time for producing TG-43 parameters was about 29.4 min in case of g = 20, L = 7 and S = 16.

Conclusion: The good agreement between the results of this study and previous reports and high computational speed suggest that SMARTEPANTS could be extended to a real-time treatment planning system for (125)I brachytherapy treatments.
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http://dx.doi.org/10.4103/0973-1482.106576DOI Listing
July 2013
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