Reza Radiation Oncology Center

Mashhad, Iran

Reza Radiation Oncology Center

Mashhad, Iran
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Salek R.,Mashhad University of Medical Sciences | Tabrizi F.V.,Reza Radiation Oncology Center | Ghaffarzadegan K.,Razavi Hospital | Sabouri G.,Mashhad University of Medical Sciences | Fanipakdel A.,Mashhad University of Medical Sciences
Iranian Journal of Cancer Prevention | Year: 2017

Background: Breast carcinoma is not a homogenous disease. It is divided into 5 pathological subtypes of luminal1, luminal2, strongly Her2 positive, basal like, and normal breast like. Basal like breast carcinoma that accounts for about 15% of all breast cancers has an aggressive clinical behavior with the features of high nuclear grade, negative estrogen receptor, progesterone receptor, and Her2 reactivity (triple negative). Objectives: We aimed at identifying the prevalence of basaloid phenotype among triple negative (TN) cases in our region via immunohistochemistry (IHC) staining using basaloid markers. Methods: We reviewed breast cancer patients in Omid and Imam Reza hospitals, Mashhad, Iran, between 2003 and 2007. We obtained the paraffin blocks from TN cases for immune-staining using cytokeratin 5/6 (CK5/6), cytokeratin 14 (CK14) and epidermal growth factor receptor1 (EGFR1) markers. Results: The incidence of TN disease among breast cancers was 21% (156/747). Based on IHC reactivity with at least one of the basaloid markers, from 59 available samples, 44 (75.4%) were basaloid. Conclusions: In our region, most triple negative tumors were basal like breast cancer (BLBC). Among these cases, most immune-reactivity was observed for EGFR1, followed by CK14 and CK5/6. © 2017, Iranian Journal of Cancer Prevention.


Sheykhoo A.,Ferdowsi University of Mashhad | Sheykhoo A.,Reza Radiation Oncology Center | Abdollahi S.,Reza Radiation Oncology Center | Hadizadeh Yazdi M.H.,Ferdowsi University of Mashhad | And 3 more authors.
Reports of Practical Oncology and Radiotherapy | Year: 2017

Aim This study deals with Monte Carlo simulations of the effects which the 550 TXT carbon fiber couch can have on the relevant parameters of a 6 MV clinical photon beam in three field sizes. Background According to the reports issued by the International Commission on Radiation Units and Measurements (ICRU), the calculated dose across a high gradient distribution should be within 2% of the relative dose, or within 0.2 cm of the isodose curve position in the target volume. Nowadays, the use of posterior oblique beam has become a common practice. It is clear that, in radiotherapy, the presence of the couch affects the beam intensity and, as a result, the skin dose. Materials and methods Firstly, Siemens linear accelerator validation for 6 MV photon beam was performed, and satisfactory agreement between Monte Carlo and experimental data for various field sizes was observed. Secondly, the couch transmission factor for the reference field size and depth was computed, and the skin dose enhancement by the couch was assessed. Results The largest impact of the carbon fiber couch effect was observed for the 5 × 5 cm2 field size. Such evaluation has not been reported for this couch before. Conclusion Despite providing minimal attenuation for the primary radiation, the assumption that carbon fiber couches are radiotranslucent is not valid, and the effects of couches of this type on the transmission factor, and on the skin dose should be carefully investigated for each field size and depth. © 2016 Greater Poland Cancer Centre


Bahreyni Toossi M.T.,Mashhad University of Medical Sciences | Ghorbani M.,Mashhad University of Medical Sciences | Akbari F.,Reza Radiation Oncology Center | Mehrpouyan M.,Sabzevar University of Medical science | Sobhkhiz Sabet L.,Reza Radiation Oncology Center
Australasian Physical and Engineering Sciences in Medicine | Year: 2015

The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 × 10 cm2 applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beam’s energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 μGy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided. © 2015 Australasian College of Physical Scientists and Engineers in Medicine


Bahreyni Toossi M.T.,Mashhad University of Medical Sciences | Ghorbani M.,Mashhad University of Medical Sciences | Akbari F.,Reza Radiation Oncology Center | Sabet L.S.,Mashhad University of Medical Sciences | Mehrpouyan M.,Sabzevar University of Medical science
Journal of Radiotherapy in Practice | Year: 2013

Background Electron mode is used for treatment of superficial tumours in linac-based radiotherapy. Purpose The aim of present study is simulation of 8, 12 and 14 MeV electrons from a Siemens Primus linac using MCNPX Monte Carlo (MC) code and verification of the results based on comparison of the results with the measured data. Materials and methods Electron mode for 8, 12 and 14 MeV electron energies of a Siemens Primus linac was simulated using MCNPX MC code. Percent depth dose (PDD) data for 10 × 10, 15 × 15 and 25 × 25 cm2 applicators obtained from MC simulations were compared with the corresponding measured data. Results Gamma index values were less than unity in most of points for all the above-mentioned energies and applicators. However, for 25 × 25 cm2 applicator in 8 MeV energy, 10 × 10 cm2 applicator and 15 × 15 cm2 applicator in 14 MeV energy, there were four data points with gamma indices higher than unity. However among these data points, there are a number of cases with relatively large value of gamma index, these cases are positioned on the bremsstrahlung tail of the PDD curve which is not normally used in treatment planning. Conclusion There was good agreement between the results of MC simulations developed in this study and the measured values. The obtained simulation programmes can be used in dosimetry of electron mode of Siemens Primus linac in the cases in which it is not easily feasible to perform experimental in-phantom measurements. Copyright © Cambridge University Press 2013.


PubMed | Sabzevar University of Medical science, Mashhad University of Medical Sciences and Reza Radiation Oncology Center
Type: Journal Article | Journal: Australasian physical & engineering sciences in medicine | Year: 2016

The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 10 cm(2) applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beams energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 Gy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided.


PubMed | Mashhad University of Medical Sciences, Comprehensive Cancer Centers of Nevada and Reza Radiation Oncology Center
Type: Journal Article | Journal: Journal of biomedical physics & engineering | Year: 2016

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.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 EBT3 films. Films were scanned by a Microtek color scanner. Dose values from two films in corresponding points were compared.In the investigation of calibration, net optical density (NOD) of EBT radiochromic is more than the EBT3 radiochromic film. The highest percentage difference between NODs of two films is related to 0.75 Gy and equals to 14.19%. The lowest value is related to 0.2 Gy dose and is equal to 3.31%. The highest percentage difference between two films on the RANDO phantom in breast cancer fields is 13.51% and the minimum value is equal to 0.33%.From the comparison between the two films, most of the points show differences in dose in the measurements in fields of breast cancer radiotherapy. These differences are attributed to the thickness of the active layers, the overall thickness of the films, and the difference in the calibration fitted functions. The advantage of EBT film over EBT3 is a higher sensitivity; on the other hand EBT3 film allows to use its both sides in the scanning process and it is a new version of this film type.


Bahreyni Toossi M.T.,Mashhad University of Medical Sciences | Abdollahi M.,Mashhad University of Medical Sciences | Abdollahi M.,Reza Radiation Oncology Center | Ghorbani M.,North Khorasan University of Medical Sciences
Reports of Practical Oncology and Radiotherapy | Year: 2013

Aim: Stepping source in brachytherapy systems is used to treat a target lesion longer than the effective treatment length of the source. Cancerous lesions in the cervix, esophagus and rectum are examples of such a target lesion. Background: In this study, the stepping source of a GZP6 afterloading intracavitary brachytherapy unit was simulated using Monte Carlo (MC) simulation and the results were used for the validation of the GZP6 treatment planning system (TPS). Materials and methods: The stepping source was simulated using MCNPX Monte Carlo code. Dose distributions in the longitudinal plane were obtained by using a matrix shift method for esophageal tumor lengths of 8 and 10cm. A mesh tally has been employed for the absorbed dose calculation in a cylindrical water phantom. A total of 5×108 photon histories were scored and the MC statistical error obtained was at the range of 0.008-3.5%, an average of 0.2%. Results: The acquired MC and TPS isodose curves were compared and it was shown that the dose distributions in the longitudinal plane were relatively coincidental. In the transverse direction, a maximum dose difference of 7% and 5% was observed for tumor lengths of 8 and 10. cm, respectively. Conclusion: Considering that the certified source activity is given with ±10% uncertainty, the obtained difference is reasonable. It can be concluded that the accuracy of the dose distributions produced by GZP6 TPS for the stepping source is acceptable for its clinical applications. © 2012 Greater Poland Cancer Centre.


Mohammadi N.,Ferdowsi University of Mashhad | Miri-Hakimabad H.,Ferdowsi University of Mashhad | Rafat-Motavlli L.,Ferdowsi University of Mashhad | Akbari F.,Reza Radiation Oncology Center | Abdollahi S.,Reza Radiation Oncology Center
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015

Despite the importance of photoneutrons doses produced in the high-energy linear accelerators, currently they are not considered in the treatment planning systems. Therefore, it is necessary to characterize the photoneutrons produced around the linacs. For this purpose, the main components of head of 15 MV Siemens Primus were simulated using MCNPX 2.6. Neutron contamination was calculated in the treatment room at the isocenter. The maximum dose equivalent of neutrons was found in 25 cm × 25 cm field size. Neutron spectrum was also measured applying the Bonner sphere with gold foils and artificial neural network as unfolding method. © 2015, Akadémiai Kiadó, Budapest, Hungary.


Mohammadi N.,Ferdowsi University of Mashhad | Miri-Hakimabad H.,Ferdowsi University of Mashhad | Rafat-Motavalli L.,Ferdowsi University of Mashhad | Akbari F.,Reza Radiation Oncology Center | Abdollahi S.,Reza Radiation Oncology Center
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015

Dose due to neutrons resulting from high-energy linear accelerator is not detailed in routine treatment planning, though this information is potentially important for better estimates of health risks including secondary cancers. In this study, the neutron contaminations were evaluated in the patient-specific voxel phantom for the treatment of prostate cancer using MCNP code. The results showed that the neutron organ doses are independent from the distance between studied organs and treatment area, and unlike the photon dose, the neutron dose distribution is almost homogeneous in the patient body. © 2014, Akadémiai Kiadó, Budapest, Hungary.


PubMed | Ferdowsi University of Mashhad, Mashhad University of Medical Sciences, University of South Australia and Reza Radiation Oncology Center
Type: Journal Article | Journal: Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology | Year: 2016

This study deals with Monte Carlo simulations of the effects which the 550 TXT carbon fiber couch can have on the relevant parameters of a 6MV clinical photon beam in three field sizes.According to the reports issued by the International Commission on Radiation Units and Measurements (ICRU), the calculated dose across a high gradient distribution should be within 2% of the relative dose, or within 0.2cm of the isodose curve position in the target volume. Nowadays, the use of posterior oblique beam has become a common practice. It is clear that, in radiotherapy, the presence of the couch affects the beam intensity and, as a result, the skin dose.Firstly, Siemens linear accelerator validation for 6MV photon beam was performed, and satisfactory agreement between Monte Carlo and experimental data for various field sizes was observed. Secondly, the couch transmission factor for the reference field size and depth was computed, and the skin dose enhancement by the couch was assessed.The largest impact of the carbon fiber couch effect was observed for the 55cmDespite providing minimal attenuation for the primary radiation, the assumption that carbon fiber couches are radiotranslucent is not valid, and the effects of couches of this type on the transmission factor, and on the skin dose should be carefully investigated for each field size and depth.

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