Publications by authors named "Fatemeh Seif"

4 Publications

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Comparison of dosimetric parameters of small-field electron beams between Advanced Markus, Semiflex 3D, and Diode E responses.

Radiol Phys Technol 2020 Sep 20;13(3):296-305. Epub 2020 Jul 20.

Department of Medical Physics, School of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran.

The usage of dosimetry of small fields in radiotherapy to measure radiation dose is difficult because of high-dose gradients, lateral electronic disequilibrium, and detector volume effects. In this study, three dosimeters namely, Markus, Semiflex 3D, and Diode E were tested using the Elekta-accelerator electron beams. The electron beam parameters, penumbra, and output factor were determined using these dosimeters for each field size and energy. According to the results, Diode E and Advanced Markus exhibited the greatest difference in Rq among the electron beam parameters. Furthermore, the greatest difference in penumbra was observed between Diode E and Advanced Markus for the field size of 3 cm at 10 MeV. In terms of output factor, three dosimeters exhibited the greatest difference between Diode E and Advanced Markus for the field size of 3 cm at 10 MeV. The findings indicate that the Semiflex 3D can be regarded as an appropriate dosimeter for electron small-field dosimetry.
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September 2020

Comparison of Photon-electron and Photon Radiotherapy for Supraclavicular Lymph Nodes of Mastectomy Patients with Left-sided Breast Cancer.

J Cancer Prev 2020 Mar;25(1):48-54

Department of Medical Physics, School of Paramedical Sciences, Isfahan University of Medical Sciences and Khansari Hospital, Isfahan, Iran.

The aim of radiotherapy is to deliver the highest possible radiation dose to the tumor and the lowest radiation to normal tissues surrounding the tumor. In the present study, lymph nodes of the supraclavicular region were treated using two therapeutic techniques, namely photon technique (PT) and combinatory photon-electron technique (CPET). We recruited 50 patients with local lymph node metastasis. The photon energies were 6-15 MV. Furthermore, the electron beam energy was 18 MeV in CPET. The study findings revealed that the mean delivered dose to target volume was 41.12 ± 2.98Gy for PT and 44.56 ± 1.90Gy for CPET. The percentage of the target volume irradiated to 90% of the prescribed dose (V90) was calculated as 74.61% ± 9.30% and 82.06% ± 9.70% for PT and CPET, respectively. The mean dose delivered to the heart and lungs was not significantly different between the two groups. Furthermore, the maximum doses delivered to the spinal cord were 12.55Gy in PT and 8.89Gy in CPET. The mean doses delivered to the thyroid gland were 39.26 and 34.89Gy in PT and CPET. According to the study results, the maximum doses delivered to the spinal cord, head of the humerus bone, and thyroid were reduced significantly as measured the CPET technique. In contrast, no significant difference was observed regarding the dose delivered to the heart and lung. The dose delivered to the supraclavicular region determined by the CPET was significantly augmented. Furthermore, the coverage of the tumor mass was optimized using the new method.
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March 2020

A Novel Algorithm in Radiation Dosimetry of Regular and Irregular Treatment Fields.

Adv Biomed Res 2019 25;8:46. Epub 2019 Jul 25.

Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

Background: The aim of this study was to design an algorithm for the calculation of monitor unit (MU) in a short time and high precision for different radiotherapy (RT) fields.

Materials And Methods: The algorithm for calculating MU for the stated patients was designed in MATLAB software. To investigate the efficiency of this algorithm, 11 regular chest fields with the sizes of 7 cm × 7 cm up to 17 cm × 17 cm were considered, and the obtained MUs were compared with MUs of 13 patients which were calculated with a "hand calculation" which is used in some RT centers for the aforementioned fields.

Results: The maximum percentage of calculation errors of regular fields at the depths of 4 and 10 cm were 1 and 0.8, respectively. The maximum and minimum percentage of calculation errors in irregular fields was 3 and 0.9, respectively. Furthermore, the maximum and minimum errors were 8.8 and 0.14, respectively. In addition, relative percentages of the MUs for irregular fields of chest and supraclavicular were 1.63 and 1.01, respectively.

Conclusion: Calculation of MUs is suggested to be performed with the novel proposed algorithm, due to reduce the treatment time, and also provide high accuracy and precision compared to hand calculation.
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July 2019

Protective properties of Myrtus communis extract against oxidative effects of extremely low-frequency magnetic fields on rat plasma and hemoglobin.

Int J Radiat Biol 2019 02 7;95(2):215-224. Epub 2019 Jan 7.

c Arak University of Medical Sciences, Infectious Diseases Research Center , Arak , Iran.

Purpose: This study investigates the protective properties of Myrtus communis extract against the oxidative effects of extremely low-frequency magnetic fields (ELFMF). Also, this study is aimed to analyze the conformational changes of hemoglobin, oxidative damages to plasma proteins and antioxidant power of plasma following exposure to ELFMF.

Materials And Methods: Adult male rats were divided into 3 groups: (1) control, (2) ELFMF exposure, and (3) ELFMF exposure after M. communis extract administration. The magnetic field (0.7 mT, 50 Hz) was produced by a Helmholtz coil for one month, 2 hours a day. The M. communis extract was injected intraperitoneally at a dose of 0.5 mg/kg before exposure to ELFMF. The oxidative effects of ELFMF were studied by evaluating the hemoglobin, methemoglobin (metHb) and hemichrome levels, absorption spectrum of hemoglobin (200-700 nm), oxidative damage to plasma proteins by measuring protein carbonyl (PCO) levels and plasma antioxidant power according to the ferric reducing ability of plasma (FRAP). The mean and standard errors of the mean were determined for each group. One-way ANOVA analysis was used to compare the means of groups. The significance level was considered to be p < .05. Moreover, artificial neural network (ANN) analysis was used to identify the predictive parameters for estimating the oxyhemoglobin (oxyHb) concentration.

Results: Exposure to ELFMF decreased the FRAP which was in concomitant with a significant increase in plasma PCO, metHb and hemichrome concentrations (p < .001). Oxidative modifications of Hb were shown by reduction in optical density at 340 nm (globin-heme interaction) and 420 nm (heme-heme interaction). Administration of M. communis extract increased FRAP values and decreased plasma POC, metHb, and hemichrome concentrations. Also, a significant increase in Hb absorbance at 340, 420, 542, and 577 nm showed the protective properties of M. communis extract against ELFMF-induced oxidative stress in erythrocytes. ANN analysis showed that optical absorption of hemoglobin at 520, 577, 542, and 630 nm and concentration of metHb and hemichrome were the most important parameters in predicting the oxyHb concentration.

Conclusions: Myrtus communis extract enhances the ability of erythrocytes and plasma to deal with oxidative conditions during exposure to ELFMF. Also, ANN analysis can predict the most important parameters in relation to Hb structure during oxidative stress.
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February 2019