اساتید - دانشکده پزشکی دانشگاه علوم پزشكي و خدمات بهداشتی درمانی تبريز

دانشکده پزشکی دانشگاه علوم پزشكي و خدمات بهداشتی درمانی تبريز - پریناز محنتی

پریناز محنتی

فیزیک پزشکی

درجه علمی : استاد

تحصیلات : Ph.D

رشته تحصیلی : فیزیک پزشکی

محل تحصیل :

تلفن : 04133364660

توضیحات :

آدرس پست الکترونیکی : parinazmehnati@yahoo.com

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مقالات ارائه شده

عنوان مقاله : Investigation of patients rights in the radiology centres

نویسندگان : Parinaz Mehnati

نام کنگره یا سمینار : The 3rd international congress in medical Law : Patient’s rights

تاریخ و محل برگزاری : 22-24 Feb 2011, Kish Island, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Evaluation of patient dose in cardio angiography procedures in angiography department of Shahid Madani hospital

نویسندگان : Parinaz Mehnati, Asgar Mesbahi

نام کنگره یا سمینار : International Conference in Radiation Protection in Medicine

تاریخ و محل برگزاری : 1-3September 2010 , Varna, Bulgaria

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Investigation on the radiation health in radiology canters in Tabriz

نویسندگان : Parinaz Mehnati, Tohid Mortazazadeh

نام کنگره یا سمینار : The first International & 4th National congress on Health education & promotion

تاریخ و محل برگزاری : 17-19 May, 2011, Tabriz Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : An Evaluation on the fraction of Non-hit cell and death after exposure to high LET accelerated ions.

نویسندگان : P .Mehnati, H. Sasaki

نام کنگره یا سمینار : First Human, Life and Radiation conference

تاریخ و محل برگزاری : 29-31Oct 2006- Rafsanjan, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Compare of three circumferential dosimeters measurement

نویسندگان : Parinaz Mehnati, Parisa Mehnati

نام کنگره یا سمینار : 9th Iranian congress of Medical Physics

تاریخ و محل برگزاری : May 2010, Iran University of Medical sciences, Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Review on the medical equipments and new findings for breast cancer diagnosis

نویسندگان : P .Mehnati

نام کنگره یا سمینار : International Congress of Nuclear Medicine& Molecular Imaging

تاریخ و محل برگزاری : 23-25 sep. 2009 Tabriz, Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Study of attention to patient safety during radiology

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 1st national Conference of health, patient safety

تاریخ و محل برگزاری : 26-28 Oct, 2011 Urmia, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Study of attention to radiation protection during the past two years

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 1st MEFOMP International Conference of Medical Physics

تاریخ و محل برگزاری : 2-4 NOV, 2011 Shiraz, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : A Comparison study of digital and film screen mammography imaging from the viewpoint of patient's rights

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 1st MEFOMP International Conference of Medical Physics

تاریخ و محل برگزاری : 2-4 NOV, 2011 Shiraz, Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Study of attention to radiation protection during the past two years in radiology centres in Tabriz

نویسندگان : P .Mehnati, J. Pirayesh Islamian

نام کنگره یا سمینار : 1st MEFOMP International Conference of Medical Physics

تاریخ و محل برگزاری : 2011 2-4NOV,Shiraz, Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : The role of academic advisor in preparing medical students for e-learning

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 4th National Conference of E-learning in Medical Sciences

تاریخ و محل برگزاری : 15-17 Feb. 2011, Tabriz, Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Expression of poly (ADP-ribose) polymerase and P53 in cultured mammalian cells exposed to accelerated heavy-ions (Fe or Ar Ions)

نویسندگان : P .Mehnati, Sasaki Hiroshi

نام کنگره یا سمینار : The 6th Iranian congress of Medical Physics

تاریخ و محل برگزاری : May 11-13 2004, Mashhad, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : An Investigation into the effects of Gamma Rays on the cell cycle phases of Chinese hamster ovary cell line

نویسندگان : P .Mehnati

نام کنگره یا سمینار : The 7th Iranian congress of Medical Physics

تاریخ و محل برگزاری : 13-15Feb. 2007 Ahvaz, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Effect of exposure to accelerated heavy-ions on the cell proliferation kinetics

نویسندگان : P .Mehnati, H. Sasaki

نام کنگره یا سمینار : 12th International congress of radiation research

تاریخ و محل برگزاری : 17-22 August 2003 Brisbane, Australia

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Biotechnology: Technology of animal cell culture

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 12th congress of Biomedical engineering

تاریخ و محل برگزاری : 16-18Nov.2005, Tabriz, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Gamma radiation induced endoreplication in the exposed CHO cell line

نویسندگان : P .Mehnati

نام کنگره یا سمینار : The 1st International congress on health Genomics & Biotechnology November

تاریخ و محل برگزاری : 24-26 2007 Tehran, Iran

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : Investigation of the breast parenchyma patterns of mammograms in the radiology

نویسندگان : Parinaz Mehnati, Hale Hoda, Hamed Alizadeh

نام کنگره یا سمینار : 8th International congress on obstetrics and gynaecology

تاریخ و محل برگزاری : 5-9 Nov, 2009, Tehran, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Incidence of polyploidy in CHO cells exposed to Gamma-rays

نویسندگان : P .Mehnati

نام کنگره یا سمینار : The 8th Iranian congress of Medical Physics

تاریخ و محل برگزاری : Jun 2009, Tehran, Iran

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : Study of attention to patient safety during radiology

نویسندگان : P .Mehnati

نام کنگره یا سمینار : اولین همایش کشوری ایمنی در نظام سلامت با محوریت ایمنی بیمار

تاریخ و محل برگزاری : 4-6 ابان 90- ارومیه

نحوه ارائه : پوستر

چکیده :

عنوان مقاله : The Relation between female body characteristics and diagnostic mammography

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 28th Iranian congress of Radiology

تاریخ و محل برگزاری : Tehran, Iran, 15-18 May 2012

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : The Relation between female body characteristics and diagnostic mammography

نویسندگان : P .Mehnati

نام کنگره یا سمینار : 28th Iranian congress of Radiology

تاریخ و محل برگزاری : Tehran,Iran, 15-18 May 2012

نحوه ارائه : سخنرانی

چکیده :

عنوان مقاله : بررسی و بهبود روند تحصیلی دانشجویان پزشکی با مشارکت اساتید راهنما

نویسندگان : پریناز محنتی

نام کنگره یا سمینار : سیزدهمين همايش کشوری اموزش پزشکی

تاریخ و محل برگزاری : ایران –91ساری- اردیبهشت11-14

نحوه ارائه : پوستر

چکیده :

مقالات چاپ شده در مجلات

عنوان مقاله : Comparison Between Film-Screen and Digital Mammography for Woman Breast Cancer Screening: Mean Glandular Dose

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Academic Journal of Cancer Research 7 (2): 162-167,

نویسندگان : Parinaz Mehnati andHamed Alizadeh

سال انتشار : 2014

چکیده :

عنوان مقاله : Gamma-Radiation Induced Endoreplication in Exposed CHO Cell Line

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : American-Eurasian Journal of Toxicological Sciences 6 (1): 25-29

نویسندگان : Parinaz Mehnati

سال انتشار : 2014

چکیده :

عنوان مقاله : An evaluation of the fraction of survivor cells and cell death after exposure to accelerated heavy ions

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : International Journal of Low Radiation 5(2). pp 104 - 112

نویسندگان : Parinaz Mehnati

سال انتشار : 2008

چکیده :

عنوان مقاله : Application of personal non-lead nano-composite shields for radiation protection in diagnostic radiology: a systematic review and meta-analysis

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Nanomedicine Journal, 7, 170-182

نویسندگان : Parinaz Mehnati, Reza Malekzadeh, Mohammad Yousefi Sooteh

سال انتشار : 2020, DOI: 10.22038/NMJ.2020.07.0001

چکیده : composites with micro- and nano-metal fillers has attracted the attention of researchers for radiation shielding applications. Lead toxicity and heaviness have oriented extensive research toward the use of non-lead composite shields. The present study aimed to systematically review the efficiency of the composite shields of various micro- and nano-sized materials as composite shields have been considered in radiation protection and diagnostic radiology. In addition, a meta-analysis was performed to determine the effects of filler size, filler type, shield thickness and tube voltage on dose reduction. The relevant studies published since 2000 were identified via searching in databases such as Google Scholar, Medline, Web of Science, Scopus, and Embase. In total, 51 articles were thoroughly reviewed and analyzed. Heterogeneity was assessed using the χ2 and I-square (I2) tests, and a fixed effects model was used to estimate the pooled effect sizes. The correlations between the subgroups were determined separately using meta-regression analysis. According to the results, the bismuth shield dose reduced from 22% to 98%, while the tungsten shield dose increased from 15% to 97%. The rate also increased from 6% to 84% in the barium sulfate shields. The combination of two metals resulted in higher attenuation against radiation, with the nano-shields exhibiting higher attenuation compared to the micro-shields, especially in low energies. Moreover, the meta-analysis indicated that the fixed effects pooled estimation of dose reduction was 89% for shield thickness (95% CI: 79-100; P<0.001), 73% for tube voltage (95% CI: 63-83; P<0.001; 50-100 kV), and 59% for tube voltage (95% CI: 35-82; P<0.001; kV>100). The single-metal personal shields made of bismuth powder had better performance than tungsten and barium sulfate. In addition, the combined metals in a shield showed more significant attenuation and dose reduction compared to the single-metal shields. Keywords • Aprons , Garments , Radiology , Non-lead shields , Patient Radiation Protection

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عنوان مقاله : Assessment of the effect of Nano Composite Shield on Radiation Risk Prevention to Breast during Computed Tomography

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Iran j radial.96002, 17(1):e96002

نویسندگان : Parinaz Mehnati, Reza Malekzade, Baharak Divband and Mohammad Youseﬁ Sooteh.

سال انتشار : 2020. doi:10.5812/iranjradiol.96002, 17(1):e96002

چکیده : Background: Application of nanomaterial has recently been introduced as a novel method to make a radiation shield to protect biological damage. Objectives: The purpose of this study was to evaluate the effectiveness regarding the use of Nano shield on the protection of the breast in chest CT scan. Materials and Methods: Bismuth oxide nanoparticles were prepared and synthesized in the Chemistry Laboratory of the University of Tabriz. Special tests were used to evaluate the properties of nanoparticles. Then, nano-bismuth oxide shields were designed with the silicon matrix at 10% and 15% ratios in 0.5- and 1-mm thicknesses, respectively. The dosimetry process was performed by thermoluminescent dosimeters (TLD) dosimeters in the skin and fourth layers of the breast in the chest CT scan. Also, signals and noises of the images were obtained to assess the effects of shield on image quality. Nano particles size was equal to 24 nm and they were spherical in shape. The distribution of nanoparticles in the silicone matrix was approved by scanning electron microscope energy dispersive spectroscopy (SEM-EDS). Results: Nano bismuth shields reduced the dose value by 9% and 15% in the skin layer related to 10% and 15% bismuth nanoparticles ratio (0.5 mm thickness), respectively. Also, by increasing shield thickness to 1 mm, the dose of skin layer was reduced by 18% and 24% related to 10% and 15% of bismuth nanoparticles ratio, respectively. Analysis of CT image showed a 10% increase in the noise related to the 10% bismuth shield. Conclusion: The nano bismuth composite shield with different ratios and thicknesses show significant dose reduction in the breast. This could play a role in breast cancer prevention during chest CT scan. Keywords: Nano Bismuth Oxide, Composite Shield, Breast Cancer, Image Quality

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عنوان مقاله : Functional response difference between diabetic /normal cancerous patients to inflammatory cytokines and oxidative stresses after radiotherapy

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Reports of practical oncology and Radiotherapy, doi.org/10.1016/j.rpor.2020.06.008

نویسندگان : Parinaz Mehnati, Behzad Baradaran, Fatemeh Vahidian, Susan Naderiazam

سال انتشار : 2020

چکیده : Diabetes, which is considered as a chronic metabolic disorder leads to an increase in inflammatory cytokines and oxidative stresses. Studies have shown several functional differences in the oxidative stress and inflammatory cytokines responses in diabetic/normal cancerous patients candidate for radiotherapy. Also, radiotherapy as a cancer treatment modality is known as a carcinogen due to oxidative damage via generation of reactive oxygen metabolites and also causing inflammation of the tissue by increasing the inflammatory cytokines. Therefore, the consequence of diabetes on oxidative stress and increased inflammatory factors and synergistic effects of radiotherapy on these factors cause complications in diabetics undergoing radiotherapy. It is considered as one of the most interesting objectives to control inflammation and oxidative stress in these patients. This review aims to concentrate on the influence of factors such as MPO, MDA, IL-1, and TNF- in diabetic patients by emphasizing the effects related to radiation-induced toxicity and inflammation by proposing therapeutic approaches which could be helpful in reduction of the complications Keywords: Diabetes Inflammation Radiotherapy Oxidative stress Immune system

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عنوان مقاله : Predicting the Risk of Radiation Pneumonitis and Pulmonary Function Changes after Breast Cancer Radiotherapy

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : J Biomed Phys Eng, JBPE465241587843000.pdf.

نویسندگان : Mehnati P, Ghorbanipoor M, Mohammadzadeh M, Nasiri Motlagh B, Mesbahi

سال انتشار : 2020

چکیده : ABSTRACT Background: Radiotherapy plays an important role in the treatment of breast cancer. In the process of radiotherapy, the underling lung tissue receives higher doses from treatment field, which led to incidence of radiation pneumonitis. Objective: The present study aims to evaluate the predictive factors of radiation pneumonitis and related changes in pulmonary function after 3D-conformal radiotherapy of breast cancer. Material and Methods: In prospective basis study, thirty-two patients with breast cancer who received radiotherapy after surgery, were followed up to 6 months. Respiratory symptoms, lung radiologic changes and pulmonary function were evaluated. Radiation pneumonitis (RP) was graded according to common terminology criteria for adverse events (CTCAE) version 3.0. Dose-volume parameters, which included percentage of lung volume receiving dose of d Gy (V5 -V50) and mean lung dose (MLD), were evaluated for RP prediction. Pulmonary function evaluated by spirometry test and changes of FEV1 and FVC parameters. Results: Eight patients developed RP. Among the dose-volume parameters, V10 was associated to RP incidence. When V10<40% and V10≥40% the incidences of RP were 5.26% and 61.54%, respectively. The FEV1 and FVC had a reduction 3 and 6 months after radiotherapy, while only FEV1 showed significant reduction. The FEV1 had more reduction in the patients who developed RP than patients without RP (15.25±3.81 vs. 9.2±0.93). Conclusion: Pulmonary function parameters, especially FEV1, significantly decreased at 3 and 6 months after radiotherapy. Since most patients with breast cancer who developed RP did not show obvious clinical symptoms, so spirometry test is beneficial to identify patients with risk of radiation pneumonitis. Keywords Breast Cancer; Radiation Pneumonitis; 3-D Conformal Radiotherapy; Spirometry; Lung

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عنوان مقاله : Assessment of Patient Dose with Special Look at Pediatrics during Cardiovascular Imaging

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Biomed Phys Eng, 10(1):51-58

نویسندگان : Mehnati P, Asghari Jafarabadi M, Danaee L

سال انتشار : , doi: 10.31661/jbpe.v0i0.902.2020

چکیده : ABSTRACT Aim: During interventional cardiology processes, patients especially women and children receive high radiation doses due to their sensitivities. In this study, we evaluated a pediatric patient dose separately in those undergone intervention cardiac procedure. Material and Methods: IIn a public hospital with 252 patients, Entrance Skin Dose (ESD) and Dose-Area Product (DAP) were recorded. Prior to the beginning of fluoroscopic procedure, the chest thickness and Body Mass Index (BMI) of patients were measured. Furthermore, kV, mAs, an angle of tube and time of angiography and angioplasty were recorded. Results: Children ratio to all patients underwent the cardiovascular imaging was 1.8. The means of patients’ ESD, DAP and fluoroscopy time were 178.3±17 mGy, 1123.6±11 μGycm2 and 281.4±181.2 s, respectively for coronary angiography. In coronary angioplasty, the increase in ESD, DAP and fluoroscopy times were observed. In children with congenital heart disease, ESD mean, DAP and fluoroscopy time were 24.0±9.8 mGy, 147.8±62 μGycm2 , and 552±72s, respectively. The females were 96.8 under 30 years and their dose mean was 276±37 mGy, 368±24 μGycm2 for ESD and DAP received, respectively with 376s fluoroscopy time. More than 37% of patients had (25-30) BMI. The relation between the patients’ BMI and DAP was significant (p=0.0001). Mean mAs was 359±34 and kV was 71.23±2.7. Above all, a direct and significant correlation was found between the patients’ chest thickness with variation kV (p=0.037, r=0.11) and mAs (p<0/001, r =0/28). Conclusion: The results demonstrated that the number of children referred to the cardiologic part of the heart and the dose rate received by them during this test were higher than the data provided for children in developing countries, thus the factors causing such diseases require more attention. Moreover, the number of women was more than twice the referred patients to the heart imaging center, the dose received by these women can be a cause of maternal diseases in children. Paying attention to the child’s perception of high-fluorescence time is necessary in comparison with total angiography time in order to reduce the number of radiation injuries among pediatrics. Keywords Patient Dose, Angiography, Angioplasty, Radiation Protection, Dose-area Product (DAP), Entrance Skin Dose (ESD), Children Dose

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عنوان مقاله : CT Role in the Assessment of Existence of Breast Cancerous Cells

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : The Journal of Biomedical Physics and Engineering (JBPE), 7,217-224.

نویسندگان : Mehnati P, Jafari Tirtash M, Ghavami M

سال انتشار : 2020.DOI: http://dx.doi.org/10.22086/jbpe.v0i0.38

چکیده : ABSTRACT Aim: CT number (HU) and linear attenuation coefficient contain useful information which can be determined during usual CT scanning for the prediction of breast cancerous cells existence based on hemoglobin concentration. Methods: This study used breast phantom containing major and minor vessels with diameters of 10 and 5 mm, respectively. The major vessels are filled by water, fat, hemoglobin (Hb) as a normal and 4× concentration of hemoglobin (4×Hb) as a cancerous breast cells, then scanned by single slice CT (GE, Hi Speed) 120 kVp, 100 mA for the determination of linear attenuation coefficient (µL ). Results: The CT numbers were for water (-7 to +7 HU), Hb (22±6 HU) and 4×Hb (80±4 HU). The difference between Hb and 4×Hb was significant (p <0.000). Minimum µL was 0.1190±0.00680 cm-1 for fat and maximum was 0.1449±0.00794 cm-1 for 4×Hb. Conclusion: The study of CT number and linear attenuation coefficient of different concentration of Hb provides a possibility for early predicting of breast cancerous cells existence (4×Hb). Keywords CT Number, Linear Attenuation Coefficient, Breast Cancer

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عنوان مقاله : Use of bismuth shield for protection of superficial radiosensitive organs in patients undergoing computed tomography: a literature review and metaanalysis

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Radiol Phys Technol, 12(1):6-25. DOI: 10.1007/s12194-019-00500-2.

نویسندگان : Parinaz Mehnati, Reza Malekzadeh, Mohammad Yousefi Sooteh

سال انتشار : 2019

چکیده : Abstract The study aimed to assess the effect of bismuth (Bi) shielding on dose reduction and image quality in computed tomography (CT) through a literature review. A search was conducted in the following databases: Web of Science, PubMed, Google Scholar, and Scopus. Studies that reported estimated dose reduction with bismuth shielding during imaging of the eye, thyroid, and breast were included, and a meta-regression analysis was used to examine the influence of the CT scanner type on the dose reduction. The studies included a total of 237 patients and 34 pediatric and adult anthropomorphic phantoms for whom the radiation dose was reported. Bismuth shielding was recommended in 88.89% of the studies based on the maintenance of appropriate image quality under shielding. Noise associated with Bi shielding was 7.5%, 263%, and 23.5% for the eye, thyroid, and breast, respectively. The fixed-effects pooled estimate of dose reduction was 34% (95% CI: 13-55; p < 0.001) for the eye, 37% (95% CI 14-61; p < 0.001) for the thyroid, and 36% (95% CI 36-55; p < 0.001) for the breast. The image quality, usage of foams, CT scanner type, beam energies, and backscatter radiation were important factors that directly affected the efficacy of Bi shielding to reduce the radiation dose at the superficial radiosensitive organs. Keywords: Bismuth shielding; Computed tomography; Dose reduction; Image quality.

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عنوان مقاله : Influence of the size of nano- and microparticles and photon energy on mass attenuation coefficients of bismuth-silicon shields in diagnostic radiology

نویسنده رابط : Mehnati P

عنوان مجله و شماره مجله : Radiol Phys Technol, 12(3):325-334. Doi: 10.1007/s12194-019-00529-3.

نویسندگان : Malekzadeh R, Mehnati P, Yousefi M, Mesbahi A

سال انتشار : 2019

چکیده : Abstract Recent studies have shown that the particle size of the shielding material and photon energy has signifcant efects on the efciency of radiation-shielding materials. The purpose of the current study was to investigate the shielding properties of the bismuth–silicon (Bi–Si) composite containing varying percentages of micro- and nano-sized Bi particles for low-energy X-rays. Radiation composite shields composed of nano- and micro-sized Bi particles in Si-based matrix were constructed. The mass attenuation coefcients of the designed shields were experimentally assessed for diagnostic radiology energy range. In addition, the mass attenuation coefcients of the composite were comprehensively investigated using the MCNPX Monte Carlo (MC) code and XCOM. The X-ray attenuation for two diferent micro-sized Bi composites of radii of 50 µm and 0.50 µm showed enhancement in the range of 37–79% and 5–24%, respectively, for mono-energy photons (60–150 keV). Furthermore, the experimental and MC results indicated that nano-structured composites had higher photon attenuation properties (approximately 11–18%) than those of micro-sized samples for poly-energy X-ray photons. The amount of radiation attenuation for lower energies was more than that of higher energies. Thus, it was found that the shielding properties of composites were considerably strengthened by adding Bi nano-particles for lower energy photons. Keywords Bismuth · Composite shield · Nano-particles · Mass attenuation coefcient · MCNPX

عنوان مقاله : New Bismuth Composite Shield for Radiation Protection of Breast during Coronary CT Angiography

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Iran J Radiol, 16(3):1-7. Doi: 10.5812/iranjradiol.84763

نویسندگان : Parinaz Mehnati, Reza Malekzad, Mohammad Youseﬁ Sooteh

سال انتشار : 2019

چکیده : Abstract Background: The main problem with coronary computed tomography angiography (CCTA) scan is the extreme exposure of patients during imaging. Bismuth belt shield is a new design to minimize the received dose in CCTA. Objectives: The purpose of this study was to design and construct new bismuth-silicon composite shields to reduce the risk of ionizing radiation during CCTA, along with an examination of the diagnostic capability of the image for the physician. Materials and Methods: Dose reduction was calculated by placing thermoluminescent dosimeters (TLDs) in skin and glandular position for breast dose measuring in the multi detector CT. CCTA scans were performed with new 10% and 15% bismuth composite shields with 1 mm and 1.5 mm thicknesses. Image quality was assessed by CT numbers and noise evaluation. Results: The breasts recorded dose without using shield were 7 - 8.90 mGy related to large or normal breasts and skin or glandular dose. The results of using 10% and 15% bismuth composite shields induced to dose reduction 9% - 31% depending on breast size, shield thickness and skin or gland position. There was a significant relationship between the reduction of breast doses and the thickness of the shields, bismuth weight percentage, the size of the breast and the dosimetry in the skin or gland. The mean noise increased from 8% to 33% in the breast position and from 4% to 25% in regions of Interest (ROIs) in locations of coronary arteries. Conclusion: The new belt bismuth-silicon shields have the potential to reduce breast dose by conserving image quality for acceptable diagnosis in CCTA. Keywords: Belt Bismuth-Silicon Shield, Coronary CT Angiography, Breast Dose Reduction, Image Quality

عنوان مقاله : Bismuth Silicon and Bismuth Polyurethane Composite Shields for Breast Protection in Chest Computed Tomography Examination

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Journal of Medical Physics, 43: 61-65.

نویسندگان : Parinaz Mehnati1, Mehran Arash, Parisa Akhlaghi

سال انتشار : 2018

چکیده : The article aims at constructing protective composite shields for breasts in chest computed tomography and investigating the effects of applying these new bismuth composites on dose and image quality. Polyurethane and silicon with 5% of bismuth were fabricated as a protective shield. At first, their efficiency in attenuating the X‑ray beam was investigated by calculating the total attenuation coefficients at diagnostic energy range. Then, a physical chest phantom was scanned without and with these shields at tube voltage of 120 kVp, and image parameters together with dose values were studied. The results showed that these two shields have great effects on attenuating the X‑ray beam, especially for lower energies (<40 kV), and in average, the attenuation coefficients of bismuth‑polyurethane composite are higher in this energy range. The maximum relative differences between the average Hounsfield units (HUs) and noises of images without and with shield for both composites in 13 regions of interest were 4.5% and 15.7%, respectively. Moreover, primary investigation confirmed the ability of both shields (especially polyurethane‑bismuth composite) in dose reduction. Comparing these two composites regarding the amount of dose reduction, the changes in HU and noise, and attenuation coefficients in diagnostic energy range, it seems that polyurethane composite is more useful for dose reduction, especially for higher tube voltages. Keywords: Bismuth composites, breast shielding, computed tomography, dose reduction, Hounsfield unit, noise

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عنوان مقاله : Assessment of the effciency of new bismuth composite shields in radiation dose decline to breast during chest CT

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : The Egyptian Journal of Radiology and Nuclear Medicine, 49 : 1187–1189, Doi.org/10.1016/j.ejrnm.2018.06

نویسندگان : Parinaz Mehnati, Reza Malekzadehb, Mohammad Youseﬁ Sooteh, Soheila Refahi.

سال انتشار : 2018

چکیده : Background: Bismuth shield has been recently introduced for radiation protection of patient radiosensitive organs such as breast during chest CT with image diagnosis capability. The purpose of this study was to evaluate the dose reduction and image quality conserve using new bismuth-silicon composite shields during chest CT. Materials and methods: Scans were performed on a PMMA phantom using a 6-slice MDCT system. Dose reduction was calculated by placing ion-chamber in the 12 o’clock position for breast dose measuring. Chest CT scans was performed with and without new bismuth composite shields 10% by 0.5 mm and 1 mm thicknesses. Image quality was assessed by CT numbers and noise evaluation. Results: The results of using bismuth composite shields induced to dose reduction to 7% and 12% for 0.5 mm and 1 mm thicknesses, respectively. As a result of the using 0.5 mm and 1 mm bismuth composite shields, the mean CT numbers and noise increased by a factor of 0.01 and 0.02 and also from 0.08 to 0.13, respectively. Significant dose decline was measured and no relevant noise was found. Conclusion: Results showed that new bismuth-silicon composite shields have good potential to breast dose reduction with smallest noise for diagnosis in chest CT.

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عنوان مقاله : Synthesis and characterization of nano Bi2O3 for radiology shield

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Nanomed. J. 5(4): 222-226. DOI: 10.22038/nmj.2018.05.00006

نویسندگان : Parinaz Mehnati, Mohammad Yousefi Sooteh, Reza Malekzadeh, Baharak Divband

سال انتشار : 2018

چکیده : ABSTRACT Objective (s): Recently, the use of nanoparticles in medicine has increased for radiation protection purpose. Thus the aim of this study was to use nano Bi2 O3 in prepared shield for dose reduction during medical imaging. Materials and Methods: Nano Bi2 O3 shield with 90% silicon and 10% nano Bi2 O3 was prepared and dosimetry test was down in radiology by PTW DIADOS E dosimeter. Results: The mean dose without using nano Bi2 O3 shields were 421 µGy, 733 µGy and 1110 µGy for 60, 80 and 100 kVp, respectively. After applying 0.5 mm thickness of nano Bi2 O3 shield, dose reduction in 60, 80 and 100 kVp was 42%, 35% and 31%, respectively. A comparison between increasing energy from 60 to 100 kVp and dose reduction showed a significant reverse effect. Conclusion: The results indicate that the new shields containing nano Bi2 O3 particles have a high X-rays attenuation ability but the attenuation property of the shields decreased by increasing the energy. Based on the results, this new shield can help social health and reduce the radiation risk. Keywords: Attenuation, Nano Bi2 O3 , Shields, Radiography

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عنوان مقاله : Near-Infrared Visual Differentiation in Normal and Abnormal Breast Using Hemoglobin Concentrations

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : J Lasers Med Sci, 9(1):50-57. doi:10.15171/jlms.2018.11

نویسندگان : Parinaz Mehnati, Sirous Khorram, Mohammad Sadegh Zakerhamidi, Farhood Fahima.

سال انتشار : 2017

چکیده : Abstract Introduction: Near-infrared (NIR) optical imaging is a non-ionizing modality that is emerging as a diagnostic/prognostic tool for breast cancer according to NIR differentiation of hemoglobin (Hb) concentration. Methods: The transmission values of LED-sourced light at 625 nm were measured by power meter to evaluate the optical properties of Hb in breast phantom containing major and minor vessels. For the simulation of blood variations in cancerous breast condition, we prepared 2 concentrations of pre-menopausal Hb and 4 concentrations of post-menopausal Hb and, for comparison with normal tissue, one concentration of Hb injected inside the phantom’s vessels. Imaging procedure on the phantom was also conducted by LED source and CCD camera. The images from the experiments were compared with the results obtained from the images analyzed by MATLAB software. Finally, mammography of phantom including various concentration of Hb was prepared. Results: The transmitting intensities of NIR in blood containing 1, 2 and 4 concentrations of Hb in the major vessels were 52.83±2.85, 43.00±3.11 and 31.17±2.27 µW, respectively, and in minor vessels containing similar Hb concentrations were 73.50±2.43, 60.08±5.09 and 42.42±4.86 µW, respectively. The gray-scale levels on the major vessel were about 96, 124, 162 and on the minor vessel about 72, 100, 130 measured for 1, 2 and 4 Hb concentrations, respectively. The sensitivity and specificity of NIR imaging differentiation were 97.4% and 91.3%, respectively. Conclusion: Significant differences in transmitting intensity, optical imaging as well as software analysis of images were observed for 1, 2 and 4 concentrations of Hb in major and minor breast phantom vessels. Differentiation capability of minor vessels was higher than major vessels for Hb concentrations. Despite a good detection for location of vessels by mammography, it could not show differences between vessels with various concentrations. However, NIR optical imaging demonstrated a good image contrast for showing vessels in terms of concentration. This study recommends NIR optical imaging for prescreening breast cancer due to its potential for early diagnosis. Keywords: Hemoglobin concentrations; Imaging; Near-infrared; Optical properties.

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عنوان مقاله : Reducing Radiation Doses in Female Breast and Lung during CT Examinations of Thorax Scanners.

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : DOI: http://dx.doi.org/10.22086/jbpe.v0i0.462

نویسندگان : Mehnati P, Ghavami M, Heidari H

سال انتشار : 2017

چکیده : Background: Introduction: Chest CT is a commonly used examination for the diagnosis of lung diseases, but a breast within the scanned field is nearly never the organ of interest. Objective: The purpose of this study is to compare the female breast and lung doses using split and standard protocols in chest CT scanning. Materials and Methods: The sliced chest and breast female phantoms were used. CT exams were performed using a single-slice (SS)- and a 16 multi-slice (MS)- CT scanner at 100 kVp and 120 kVp. Two different protocols, including standard and split protocols, were selected for scanning. The breast and lung doses were measured using thermo-luminescence dosimeters which were inserted into different layers of the chest and breast phantoms. The differences in breast and lung radiation doses in two protocols were studied in two scanners, analyzed by SPSS software and compared by t-test. Results: Breast dose by split scanning technique reduced 11% and 31% in SS- and MS- CT. Also, the radiation dose of lung tissue in this method decreased 18% and 54% in SS- and MS- CT, respectively. Moreover, there was a significant difference (p< 0.0001) in the breast and lung radiation doses between standard and split scanning protocols.

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عنوان مقاله : Estimation of absorbed dose of radiosensitive organs and effective dose in patients underwent abdominopelvic spiral CT scan using impact CT patient dosimetry

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Tehran University Medical Journal, 75, 2: 103-112

نویسندگان : Parinaz Mehnati, Auyub Amirnia, Nasrollah Jabbari

سال انتشار : 2017

چکیده : زمینه و هدف: در ناحیه شکم و لگن بـهدلیل بـودن ارگانهـاي حسـاس بـه پرتـو و افـزایش تعـداد درخواسـتهاي آزمونهاي سیتیاسکن، نگرانیها نسبت به افزایش دوز بیماران بهشدت افزیش یافته اسـت. از ایـنرو هـدف از ایـن مطالعه تعیین دوز جذبی ارگانهاي حساس به پرتو و دوز موثر بیماران در سیتیاسـکن شـکم و لگـن بـا اسـتفاده از .بود ImPACT CT Patient Dosimetry نرمافزار روش بررسی: این مطالعه توصیفی-مقطعی، از آبان تا اسفند سال 1394 در بیمارستان امام رضا (ع) ارومیه انجام شد. دادههاي دموگرافی و دوزیمتري 100 بیمار اسکن شده با سیتیاسکن 6 اسلایسی، از طریق فرمهاي جمعآوري دادهها، گردآوري شدند. براي تعیین دوز جذبی ارگانهاي حساس به پرتو و در نهایت دوز موثر بیماران، نرمافزار ImPACT CT Patients Dosimetry Calculator (version 1.0.4, Imaging Performance Assessment on محاسباتی .گرفت قرار استفاده مورد Computed Tomography, www.impactscan.org) یافتهها: نتایج این مطالعه نشان داد که میانگین و انحرافمعیار دوز بیماران در اسکن سیتی شکم و لگن برابر با 164/0±927/4 میلیسیورت (mSv, milliSievert (بود. مثانه در هر دو جنس بالاترین میانگین دوز ارگان را داشت که میانگین و انحرافمعیار آن در مردان 15/17±71/64 میلیگري و در زنان 48/18±56/77 میلیگري بود (001/0

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عنوان مقاله : Estimating cancer induction risk from abdominopelvic scanning with 6- and 16-slice computed tomography

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : International Journal of Radiation Biology, DOI: 10.1080/09553002.2017.12682802

نویسندگان : Parinaz Mehnati, Ayoub Amirnia & Nasrollah Jabbari

سال انتشار : 2017

چکیده : ABSTRACT Purpose: The biological effects of ionizing radiation (BEIRVII) report estimates that the risk of getting cancer from radiation is increased by about a third from current regulation risk levels. The propose of this study was to estimate cancer induction risk from abdominopelvic computed tomography (CT) scanning of adult patients using 6- and 16-slice CT scanners. Materials and methods: A cross-sectional study on 200 patients with abdominopelvic CT scan in 6- and 16-slice scanners was conducted. The dose-length product (DLP) and volume CT Dose Index (CTDIvol) values from the scanners as well as the effective dose values from the ImPACT CT patient dosimetry calculator with the biological effects of ionizing radiation (BEIRVII) method were used to estimate the cancer induction risk. Results: The mean (and standard deviation) values of CTDIvol and DLP were 6.9 (±1.07) mGy and 306.44 (± 60.57) mGy.cm for 6 slice, and 5.19 (±0.91) mGy and 219.7 (±49.31) mGy.cm for 16 slice scanner, respectively. The range of effective dose in the 6-slice scanner was 2.61 to 8.15 mSv and, in the 16-slice scanner, it was 1.47 to 4.72mSv. The mean and standard deviation values of total cancer induction risk in abdominopelvic examinations were 0.136±0.059% for men and 0.135±0.063% for women in the 6-slice CT scanner. The values were 0.126 ± 0.051% for men and 0.127 ± 0.056% for women in the 16-slice scanner. Conclusions: The cancer induction risk of abdominopelvic scanning was noticeable. Therefore, radiation dose should be minimized by optimizing the protocols and applying appropriate methods. Keywords: abdominopelvic CT scan, cancer induction risk, radiation dose, effective dose

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عنوان مقاله : Relation between Mammographic Parenchymal Patterns and Breast Cancer Risk,

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Asian Pacific Journal of Cancer Prevention, 17 (4), 2259-2263, DOI:http://dx.doi.org/10.7314/APJCP.2016.17.4.2259

نویسندگان : Parinaz Mehnati, Hamed Alizadeh, Haleh Hoda

سال انتشار : 2016

چکیده : Abstract BACKGROUND: Mammographic density determined according paranchymal patterns is a risk factor for breast cancer and its relationships with body and other breast characteristics of women is important. The purpose of the present study was to correlate breast parenchymal patterns and mammography abnormality findings with women's BMI, compressed breast thickness (CBT) and age in Tabriz city, Iran.

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عنوان مقاله : Assessing Absorption Coefficient of Hemoglobin in the Breast Phantom Using Near-Infrared Spectroscopy

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Iranian Journal of Radiology, 13(4):e31581, DOI: 10.5812/iranjradiol.31581.

نویسندگان : Parinaz Mehnati, Maede Jafari Tirtash, Mohammad Sadegh Zakerhamidi, Parisa Mehnati.

سال انتشار : 2016

چکیده : Abstract Background: Blood concentrations and oxygen saturation levels are important biomarkers for breast cancer diagnosis. Objectives: In this study, the absorption coefficient of hemoglobin (Hb) was used to distinguish between normal and abnormal breast tissue Materials and Methods: A near-infrared source (637 nm) was transmitted from major and minor vessels of a breast phantom containing 2x, 4x concentrations of oxy- and deox- hemoglobin. The absorption coefficients were determined from spectrometer (SM) and powermeter (PM) data. Results: The absorption coefficients were 0.075±0.026 cm-1 for oxygenated Hb (normal) in major vessels and 0.141±0.023 cm-1 at 4x concentration (abnormal) with SM, whereas the breast absorption coefficients were 0.099±0.017 cm-1 for oxygenated Hb (normal) in minor vessels and 0.171 ± 0.005 cm-1 at 4x concentrations with SM. A comparison of the data obtained using a spectrometer and a powermeter was not significant statistically. Conclusions: The study of the absorption coefficient data of different concentrations of Hb in normal and abnormal breasts via the diffusion of near-infrared light is a valuable method and has the potential to aid in early detection of breast abnormalities with SM and PM in major and minor vessels. Keywords: Hemoglobin, Optical Properties, Near Infrared Spectroscopy, Absorption Coefficient

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عنوان مقاله : Evaluation Of Gamma Radiation-Induced Cytotoxicity Of Breast Cancer Cells: Is There A Time-Dependent Dose With High Efﬁciency

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Indian J Cancer, 53, 25-28.

نویسندگان : Fazel M, Mehnati P, Baradaran B, Islamian PJ.

سال انتشار : 2016

چکیده : Abstract CONTEXT: Radiotherapy is one of the important treatment modalities in the management of breast cancer. AIMS: The aim of this study is to study the efficient treatment of breast cancer as related to the dose delivery. MATERIALS AND METHODS: The human breast cancer cell lines (MCF‑7) cells were cultured and exposed by 1, 2, 4, 6, 8, 10, and 20 Gy of γ‑rays. Radiation‑induced cell death was detected and evaluated, using three assay methods: Cell viability, clonogenic cell survival assay and induction of apoptosis. The cell viability was determined using trypan blue staining, 24 and 72 h post‑irradiation. The survival fraction (SF) was determined by colony counting, 14 days after exposure and the apoptotic cell death was determined using the TUNEL assay. STATISTICAL ANALYSIS USED: One‑ or two‑way analysis of variance was deemed as appropriate, followed by relevant post t‑test to determine P values. RESULTS: The difference of MCF‑7 cell death through increasing post‑radiation time from 24 to 72 h following the dose of 1, 6 and 10 Gy was found to be 2%, 9.6% and 7.14%, respectively. D0 of MCF‑7 was 220 cGy and the SF in the cells irradiated by 1 Gy and 10 Gy doses were 0.8 and 0.0001, respectively. The estimated variances were 2%, 11.1% and 8.4%, between 24 h and 72 h post‑radiation apoptosis death for 1, 6, and 10 Gy, respectively. CONCLUSIONS: The dose and time dependence inducing apoptotic death was significant (P = 0.001). The delayed mortality and apoptosis was observed in MCF‑7 cell, but the variance of total cell death and apoptosis in 24 and 72 h post‑radiation with 6 Gy was obviously more than that with other doses. Key Words: Apoptosis, dose, MCF‑7 cell

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عنوان مقاله : Comparative Efficacy of Four Imaging Instruments for Breast Cancer Screening

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Asian Pacific Journal of Cancer Preventio, 16 (15), 6177-6186

نویسندگان : Parinaz Mehnati, Maede Jafari Tirtash

سال انتشار : 2015

چکیده : Abstract Sensitivity and specificity are the two most important indicators in selection of medical imaging devices for cancer screening. Breast images taken by conventional or digital mammography, ultrasound, MRI and optical mammography were collected from 2,143,852 patients. They were then studied and compared for sensitivity and specificity results. Optical mammography had the highest sensitivity (p<0.001 and p<0.006) except with MRI. Digital mammography had the highest specificity for breast cancer imaging. A comparison of specificity between digital mammography and optical mammography was significant (p<0.021). If two or more breast diagnostic imaging tests are requested the overall sensitivity and specificity will increase. In this literature review study patients at high-risk of breast cancer were studied beside normal or sensitive women. The image modality performance of each breast test was compared for each. Keywords: Sensitivity - specificity - breast imaging - ultrasound - MRI - digital/optical mammography

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عنوان مقاله : Which Factors are Impressive on the Education Process of Medicine Students at Current Time

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Quarterly educational development of jundishapur, 6; 3, 191-197

نویسندگان : Parinaz Mehnati, Shirin Babri

سال انتشار : 2015

چکیده : چكیدٌ: ثب فٌبیت ثِ اّویت قغل پعقىی ٍ ضؾبلت زاًكگبُ زض تطثیت پعقىبى وبضآهس، پطتَاى ٍ هتقْس، زض ایي تحمیك فَاهل اثطگصاض زض فطآیٌس تحصیلی زاًكدَیبى پعقىی زض فصط وًٌَی ثطضؾی گطزیس. ایي هغبلقِ زض ثیي 110ً فط اظ زاًكدَیبى ضقتِي پعقىی زاًكگبُ فلَم پعقىی تجطیع اًدبم ٍ ثب اؾتفبزُ اظ پطؾفًبهِي هحمكؾبذتِ ثب همیبؼ لیىطت هَضز اضظیبثی لطاض گطفت. گعیٌِّبي هْن تأثیطگصاض زض فطآیٌس تحصیلی ثِ زٍ زؾتِي فَاهل زضًٍی ٍ ثیطًٍی تمؿین قسًس. اظ 110ً فط زاًكدَي پعقىی، 57 زضصس هؤًث ٍ ثمیِ هصوط ثَزًس. ایي هغبلقِ ًكبى زاز اظ فَاهل زضًٍی هؤثط، هیعاى فاللِ ثِ ضقتِي تحصیلی لجل اظ اًتربة ضقتِ زض 5/85 زضصس ٍ اهیسٍاضي ثِ اهىبى ذسهت ثِ هطزم 2/88 زضصس ظیبز ٍ ذیلی ظیبز ثَز. زض هَضز فَاهل ثیطًٍی، ضضبیتوٌسي زاًكدَیبى اظ ًحَُي آهَظـ 30 زضصس ٍ ؾغح فلوی اؾبتیس 1/49 زضصس ذیلی ظیبز ٍ یب ظیبز ثَز ٍ اضائِي پىیح آهَظقی تَؾظ هسضؼ ثطاي ّط ٍاحس زضؾی 8/81 زضصس ًمف ذیلی ظیبز ٍ ظیبز زض فطاگیطي زاقتِ اؾت. ایي هغبلقِ ًكبى زاز وِ فطایٌس تحصیلی زاًكدَیبى ثب فَاهل زضًٍی اضتجبط هؿتمین هقٌبزاضي زاضز. اظ فَاهل ثیطًٍی اؾتفبزُ اظ پىیح آهَظقی هٌبؾت ثِصَضت اثط هقٌبزاض هثجت ثَزُ ٍ هَخت وبّف ظهبى ٍ ّعیٌِ هیگطزز. ياشگان کلیدی: فطآیٌس تحصیلی، زاًكدَیبى پعقىی، فَاهل زضًٍی

عنوان مقاله : Evaluation of Mean Glandular Dose in A Full-Field Digital Mammography Unit In Tabriz, Iran

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Radiat Prot Dosimet; 142(2-4): 222-227, doi:10.1093/rpd/ncq218

نویسندگان : Alizadeh Riabi H, Mehnati P, Mesbahi A

سال انتشار : 2010

چکیده : This study was aimed at evaluating the mean glandular dose (MGD) and affecting factors during mammography examinations by a full-field digital mammography unit. An extensive quality control program was performed to assure that the unit is properly working. Required information including compressed breast thickness (CBT), breast parenchymal pattern and technical factors used for imaging were recorded. An entrance skin exposure measurement was also performed using slabs of polymethylmethacrylate with 2– 8 cm thickness. On the basis of recorded information and measured data, the MGD was estimated for 1145 mammography examinations obtained from 298 patients. Mean CBTs of 4.9 and 5.8 cm and MGDs of 2 and 2.4 mGy were observed for craniocaudal and mediolateral oblique views, respectively. Significant correlation was seen between MGD and CBT, breast parenchymal pattern and applied kVp and mAs.

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عنوان مقاله : Evaluation of Patient Radiation Dose during Angiography and Angioplasty in Angiography Department Of Shahid Madani Hospital-Tabriz.Iran

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Iranian Journal of Medical Physics 6(1): 53-59

نویسندگان : Mesbahi A, Aslanabadi N, Mehnati P, Keshtkar A

سال انتشار : 2009

چکیده : مقدمه: آنژيوگرافي و آنژيوپلاستي كرونري باعث پرتوگيري قابل توجه بيماران مي گردد . در اين پژ وهش متوسط دوز تشعش ع ي دريافتي بيماران در بخش آنژيوگرافي بيمارستان شهيد مدني تعيين شده است. ثبت گرديد . با تجزيه و تحليل اطلاعات بدست آمده متوسط دوز دريافتي بيماران در آن ژيوگرافي، آ نژيوپلاستي و براي دو حالت داخلي آن مورد سنجش واقع شد . سپس حاصلضرب دوز در مساحت براي بيماران (۲۳۶ نفر ) در حين فلوروسكوپي و فيلمبرداري مواد و روشها: دستگاه آنژيوگرافي فيليپس از نوع تقويت كننده تصوير مدل BH3000 مورد استفاده قرار گرفت . صحت دوزيمتر نتايج: مقدار متوسط دوز ۷/ ۲۳ و ۵/ ۹۱ گري سانتي متر مربع به ترتيب براي آنژيوگرافي و آنژيوپلاستي بدست آمد. دوز دريافتي فلوروسكوپي و فيلمبرداري بدست آمد . همچنين متوسط زمان فلوروسكوپي براي كل بيماران مورد مطالعه نيز بدست آمد. بيماران ناشي از فيلمبرداري ، ف لوروسكوپي و دوز مجموع براي آنژيوگرافي به ترتيب ۲ ، ۷ / ۷ و ۸ / ۳ ب رابر كمتر از آنژيوپلاستي بود . متوسط زمان فلورسكوپي در آنژيوگر افي ۹ / ۱ برابر كمتر از آنژيوپلاستي بدست آمد. بحث و نتيجه گيري: زمان فلوروسكوپي و از طرفي پرتوگيري بيماران در حين فلوروسكوپي توافق خو بي با مطالعات ديگران دارد . اما دوز دريافتي بيماران در حين آنژيوپلاستي بطور قابل توجهي بالاتر از سايرين مي باشد براي كاهش دوز دريافتي بيماران در آنژيوپلاستي استفاده از پايين ترين فريم ريت ، كوچكترين اندازه ميدان و همچن ين بازآموزي اپراتورها و تكنولوژيست ها توصيه مي گردد . (مجله فيزيك پزشكي ايران، دوره ۶ ، شماره ۱ ، پياپي (۲۲ ، ( بهار ۸۸ : ۵۹- ۵۳(

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عنوان مقاله : Comparison of Radiation Dose to Patient and Staff for Two Interventional Cardiology Units: A Phantom Study

نویسنده رابط : Mehnati Parinaz

عنوان مجله و شماره مجله : Radiat Prot Dosimet, 131(3): 399-403

نویسندگان : Mesbahi A, Mehnati P, Keshtkar A, Aslanabadi N.

سال انتشار : . 2008

چکیده : The purpose of this investigation was to measure the patient and staff dose during routine interventional cardiology procedures for an image intensifier-based and a flat detector system using a water phantom. The Integris BH3000 image intensifier-based (Philips) and the Axiom Artis flat detector-based (Siemens) angiography units were used in this study. The accuracy of tubes potential and irradiation timers and also internal dosimeters were verified and confirmed. A water phantom with a thickness of 18 cm was used for patient and staff dose measurements. For the Philips system, phantom entrance dose rates were 2.77 and 38.97 mGym2 s 21 during fluoroscopy and cineangiography. The respective dose rates for the Siemens were 1.98 and 13.46 mGym2 s 21 . Phantom entrance dose rate was 28.5 and 65% higher for the Philips system during fluoroscopy and cineangiography, respectively. Comparing the scattered dose rates at the operator location showed that the flat detector-based Siemens system delivers five times lower dose to the operator in comparison with the image intensifier-based Philips unit. The results suggest that the decrease in received dose of the patient and staff is achievable using the flat detector system. In addition, application of lead curtain and glass is recommended to lower the cardiologist dose especially for the image intensifier-based Philips system.

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عنوان مقاله : The Effect 0f Bladder Volume Changes On the Measured Electrical Impedance of the Urothelium

نویسنده رابط : Mehnati Painaz

عنوان مجله و شماره مجله : Int J Biomed Eng and Technol; 1 (3).287-292

نویسندگان : Keshtkar A, Mesbahi A, Mehnati P.

سال انتشار : 2008

چکیده : Abstract: The bio-impedance of the urinary bladder in both benign and malignant areas can be measured using the electrical impedance spectroscopy system. In this procedure, the bladder volume changes using some liquids which were expected to affect the resulting electrical impedance of the urinary bladder (in vivo and ex vivo). Different volumes of bladders were assessed to measure their impedance using different solutions. The solution volume was changed and repeated readings were made for different volumes. Despite the measured impedance demonstrated no significant relation between the impedance and the degree of the bladder existed, but there was a little dependence between them. Keywords: bladder tissue; electrical impedance; extensions; volume changes.

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عنوان مقاله : An Evaluation Of The Fraction Of Survivor Cells And Cell Death After Exposure To Accelerated Heavy Ions

نویسنده رابط : Parinaz Mehnati

عنوان مجله و شماره مجله : Int J Low Radiat; 5(2):104-12

نویسندگان : Parinaz Mehnati

سال انتشار : 2008

چکیده : Abstract: The cosmic environment is considered to include a mixture of high-energy photons and radiation particles, such as iron ions. The total radiation exposure during manned space missions contribute to heavy ions. The possibility that high Linear Energy Transfer (LET) radiation provides no ionisation within the cell target (survivor cells) and the cells with multihit events is higher due to their uniform distribution in comparison to low LET ionisation. It was explored by evaluating the fraction of survivor cells (20%) and the cells undergoing cell death (70%) in Chinese hamster ovary cells exposed to heavy ions. About 10% of the residue cells suffered from division delay and showed lethal sectoring. The Relative Biological Effectiveness (RBE) in two kinds of cell death for reproductive death and interphase death showed a similar LET dependence with a maximum of around 200 keV/µm. In this LET region, the quantity of nonsurvivor cells with reproductive death was higher than interphase death. Keywords: cosmic environment; survivor cell; cell death; heavy ions.

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عنوان مقاله : A Study on the Impact of Operator Experience on the Patient Radiation Exposure in Coronary Angiography Examinations

نویسنده رابط : Mehnati Parinaz

عنوان مجله و شماره مجله : Radiat Prot Dosim; 132(3): 319-323

نویسندگان : Mesbahi A, Aslanabadi N, Mehnati P

سال انتشار : 2008

چکیده : The aim of the current study was to investigate the effect of cardiologists’ experience on the patient received dose during coronary angiography. The exposure parameters including fluoroscopy time, total kerma-area product (KAP), total air-kerma, fluoroscopy and cine acquisition KAP and air-kerma for five senior cardiologists with the experience of 6–10 y were recorded. The range of values for fluoroscopy time and total KAP were 2.17– 4.19 min and 12.06–21.06 Gy cm2 , respectively, in our diagnostic coronary examinations, which was below the recommended reference values. The differences among cardiologists were analysed statistically using one-way ANOVA test. The fluoroscopy KAP and air-kerma results showed statistically significant differences between cardiologists. However, the experience of the cardiologists showed no relation with patient received dose. According to the results, training in radiation protection as a requisite for interventional cardiologists was recommended.

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عنوان مقاله : Dosimetric Properties Of A Flattening Filter-Free 6-MV Photon Beam A Monte Carlo Study

نویسنده رابط : Mehnati Parinaz

عنوان مجله و شماره مجله : Radiat J Med Imaging Radiat Oncol, 25(7):315-24

نویسندگان : Mesbahi A, Mehnati P, Keshtkar A, Farajollahi AR

سال انتشار : 2007

چکیده : Abstract Purpose. The dosimetric features of an unflattened 6-MV photon beam of an Elekta SL-25 linac was calculated by the Monte Carlo (MC) method. Material and methods. The head of the Elekta SL-25 linac was simulated using the MCNP4C MC code. The accuracy of the model was evaluated using measured dosimetric features, including depth dose values and dose profiles in a water phantom. The flattening filter was then removed, and beam dosimetric properties were calculated by the MC method and compared with those of the flattened photon beam. Results. Our results showed a significant (twofold) increase in the dose rate for all field sizes. Also, the photon beam spectra for an unflattened beam were softer, which led to a steeper reduction in depth doses. The decrease in the out-of-field dose and increase in the contamination electrons and a buildup region dose were the other consequences of removing the flattening filter. Conclusion. Our study revealed that, for recent radiotherapy techniques, the use of multileaf collimators for beam shaping removing the flattening filter could offer some advantages, including an increased dose rate and decreased out-of-field dose. Key words Flattening filter-free · Unflattened photon beam · Elekta SL-25 · Monte Carlo simulation

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عنوان مقاله : A Comparative Monte Carlo Study on 6MV Photon Beam Characteristics of Varian 21EX and Elekta SL-25 Linacs

نویسنده رابط : Mehnati P

عنوان مجله و شماره مجله : Iran J Radiat Res; 5(1):23-30

نویسندگان : Mesbahi A, Mehnati P, Keshtkar A

سال انتشار : 2007

چکیده : چکیده مقدمه: ذرات باردار سنگین شامل هسته های عناصری مانندآهن، آرگون، کربن ونئون هستند که همگی بار الکترونیکی مثبت دارند.برای مفید بودن این ذرات در پرتودرمانی باید تا انرژی های چندین هزار میلیون ولت شتاب داده شوند. همچنین فضای کیهانی متشکل از فونتهایی با انرژی بالا و ذرات تشعشعی است که تهدیدی برای فضانوردان در ماموریتهای طولانی فضایی بشمار میرود. بنابراین بررسی اثرات بیولوژیکی این پرتوها حائز اهمیت است. مواد وروشها: در این تحقیق وقوع مرگ اینترفازی در سلولهای همسترچینی بعد از پرتودهی با یونهای شتاب یافته کربن،نئون، آرگون وآهن با مقادیرمختلف انتقال خطی انرژی از ۱۰ الی ۲۰۰۰ کیلو الکترون ولت برمیکرومترمورد بررسی قرارگرفت. دو روش جهت بررسی مرگ اینترفازی بکار گرفته شده است. روش مستقیم توسط عکس برداری دوره ای وبا توجه به زمان وچگونگی تقسیم سلولی برای هرسلول بطور جداگانه مشاهده وثبت می گردد.در روش غیر مستقیم با استفاده از کافئین توانستیم سلولهایی را که دچار مرگ اینترفازی بودند، سریعتر شناسایی کنیم. نتایج: منحنی سلولهای پرتودیده با ایکس در مرگ اینترفازی بصورت خطی با افزایش آهنگ دز پرتوی افزایش می یابد ولی منحنی دارای شانه اولیه ای نبوده وبا افزایش دز پرتوی احتمال مرگ سلولی نیز افزایش می یابد. محدوده تغییرات مقدار انرژی برای ایجاد حداکثر اثر بیولوژیکی نسبی در مورد مرگ اینترفازی از ۱۲۰الی ۲۳۰الکترون ولت بر میکرمتراست. همچنین احتمال بروز مرگ سلولی در سطح هدف سلولهای تخمدان همسترچینی برای یونهای سنگین در حدود ۰۴/۰الی ۰۸/۰ محاسبه گردید. بحث ونتیجه گیری: افزایش انتقال خطی انرژی موجب افزایش اثر بیولوژیکی نسبی خواهد بود ودر۵۰ درصد از موارد پرتو دهی با یونهای سنگین در انرژی ۲۳۰کیلو الکترون ولت برمیکرومتر اثر بیولوژیکی نسبی به میزان حداکثر می رسد ولی بعد از آن با افزایش انرژی مقدار اثر بیولوژیکی نسبی کاهش می یابد. محدوده تغییرات مقدار انرژی برای ایجاد حداکثر اثر بیولوژیکی نسبی در مورد مرگ اینترفازی کمتر از مرگ میتوزی است.( مجله فیزیک پزشکی ایران، دوره ۴، شماره ۱۵، ۱۴،بهاروتابستان ۸۶-۸۱-۷۱)

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عنوان مقاله : Exploration of` `Over kill effect ` of high-LET Ar- and Fe-ions by evaluating the fraction of non-hit cell and Interphase death.

نویسنده رابط : Mehnati P

عنوان مجله و شماره مجله : Journal of Radiation Research, 46(3): 343-350

نویسندگان : Mehnati P., Morimoto Sh., Yatagai F. and Sasaki H

سال انتشار : 2005

چکیده : Over Kill Effect/RBE vs LET Relation/Heavy Ions/Non-hit Cell/Interphase Death. The reason why RBE for cell killing fell to less than unity (1.0) with very high-LET heavy-ions ( 40Ar: 1,640 keV/mm; 56Fe: 780, 1,200, 2,000 keV/mm) was explored by evaluating the fraction of non-hit cell (time-lapse observation) and cells undergoing interphase death (calculation based on our previous data). CHO cells were exposed to 4 Gy (30% survival dose) of Ar (1,640 keV/mm) or Fe-ions (2,000 keV/ mm). About 20% of all cells were judged to be non-hit, and about 10% cells survived radiation damage. About 70% cells died after dividing at least once (reproductive death) or without dividing (interphase death). RBE for reproductive (RBE[R]) and interphase (RBE[I]) death showed a similar LET dependence with maximum around 200 keV/mm. In this LET region, at 30% survival level, about 10% non-survivors underwent interphase death. The corresponding value for very high-LET Fe-ions (2,000 keV/mm) was not particularly high (~15%), whereas that for X-rays was less than 3%. However, reproductive death (67%) predominated over interphase death (33%) even in regard to rather severely damaged cells (1% survival level) after exposure to Fe-ions (2,000 keV/mm ). These indicate that interphase death is a type of cell death characteristic for the cells exposed to high-LET radiation and is not caused by ‘cellular over kill effect’. Both NHF37 (non-hit fraction at 37% survival) and inactivation cross-section for reproductive death (s[R]) began to increase when LET exceeded 100 keV/mm. The exclusion of non-hit fraction in the calculation of surviving fraction partially prevented the fall of RBE[R] when LET exceeded 200 keV/mm. On the other hand, the mean number of lethal damage per unit dose (NLD/Gy) showed the same LETdependent pattern as RBE[R]. These suggest that the increase in non-hit fraction and s[R] with an increasing LET is caused by enhanced clustering of ionization and DNA damage which lowers the energy efficiency for producing damage and RBE

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عنوان مقاله : Expression of (Poly ADP-Ribose) polymerase and P53 in cultured mammalian cells exposed to accelerated heavy-ions (Iron or Argon)

نویسنده رابط : Mehnati P

عنوان مجله و شماره مجله : Archives of Iranian Medicine, 6(2): 121-126

نویسندگان : Mehnati P, Sasaki H

سال انتشار : 2003

چکیده : Background – The possibility of using high-energy accelerated heavy-ion beams in radiotherapy of malignant tumors is an exciting development. Also, heavy ions comprise an important component of cosmic rays. The DNA molecule should be an important candidate target in heavy ion-induced cell lethality. Poly (ADP-ribose) polymerase (PARP) and tumor suppressor p53 are two important nuclear proteins that recognize heavy ions as a DNA damage signal. We studied the expression of PARP and p53 in cultured mammalian cells exposed to accelerated heavy ions (Fe or Ar). Methods – Chinese hamster ovary cells (CHO) and Mongolian gerbil fetal (MGF) cells were exposed to iron (Fe) or argon (Ar) ions, which are heavy ions accelerated by a ring cyclotron in Riken, Japan. We studied PARP and p53 expression as DNA strand-break recognition signal markers by immunohistochemistry assay in exposed cells to heavy ions and control cells. Results – The fraction of cells showing an elevated level of PARP in their nuclei compared to control cells after 1.5 hours of exposure to 4 Gy heavy ions was about 80%. The difference between PARP expression in CHO and MGF cells was negligible. In the immunohistochemistry assay for p53, which was performed in the Mongolian gerbil fetal cell line only, about 80% of cells showed an elevated level of p53 within the nucleus after 4 hours of exposure to 4 Gy heavy ions. However, the increase in PARP expression occurred earlier than p53 in nuclei of Mongolian gerbil fetal cells after exposure to heavy ions. About 20% of cells did not have increased PARP and p53 expression after exposure to either Fe or Ar ions. This 20% might represent a population of cells that did not receive nuclear DNA damage. Conclusion – These findings suggest that the probabilities of DNA damage after exposure to heavy ions could be evaluated based on PARP or p53 expression. The variation in expression can be related to the traversal of heavy ions through the cell nucleus and induce DNA strand-break as well as key structural components during apoptosis. Keywords · heavy ions (Fe or Ar) · PARP · p53

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عنوان مقاله : Judgement on Hit or Non-hit of CHO Cells exposed to accelerated heavy ions using division delay as indicator

نویسنده رابط : Mehnati P

عنوان مجله و شماره مجله : Fukuka Acta Medica, 3: 46-58

نویسندگان : Mehnati P., Yatagai F. and Sasaki H

سال انتشار : 2001

چکیده : Abstract The cell killing effect of ionizing radiation depends on the degree of linear energy transfer (LET).The relative biological effectiveness (RBE)reaches a maximum at LET of around 100-200 keVb/ m and decreases at higher levels.The ion clusters produced by high –LET radiation are not uniformy distributed. The incidence of nonhit cell events is higher in high LET irradiation than in the cases of low – LET irradiation.Since the cell killing effect may be related to the nuclear traversal of heavyions٫it is necessary to establish methods to distinguish the hit cells from the non- hit cells٫especially in case with high LET irradiation. Using time-lapse photography٫we first examined the hit events by observing the division delay in the cells caused by highLETirradiation.In addition٫we explored the use of CR- 39 plastics to detect the exact position of heavy – ion traversal on the surface of a flask where cells were growing. When Chinese hamster ovary(CHO_K1)cells were exposed to 4 gy of accelerated Feions(2000 keV/ m) or Ar (1640 keV/ m)-ions٫the surviving fraction decreased to about 30%in both cases of irradiation.Eighty percent of the irradiated cells٫suffered adivision delay in contrast to the remaining 20%of the cells which showed a normal division time (12-13hrs).The later 20% of the cells is considered to be a population of cells which were were not actually traversed by heavy –ions.The difference between the higher values of the surviving fraction (approximately 30%)and the non – hit cell population (20%)indicates that some hit cells can grow even after being hit by heavy – ions.The fraction of recovered with the difference between the surviving fraction and the non- hit cells.We used the Poisson distribution of the hit – events by heavy – ions among the cell population in order to calculate the fraction of cells receiving at least a single – hit in the cell nucleus (130 m 2 in average size).From this calculation we determined that 80% of the cells had a single hit to their nuclei by a heavy- ion which induced such early cellular responses as division delay.Our finding in the experiments using CR- 39 plastics as a detector for hit- sites further supported the idea that the hit lethality of a cell is related to heavy- ion traversal thought its nucleus.This study indicates the possible usefulness of both the division delay and CR- 39 plastic methods for evaluating the biological effects of heavy - ions٫especially when these two methods are combined.

دانشکده پزشکی دانشگاه علوم پزشكي و خدمات بهداشتی درمانی تبريز - پریناز محنتی

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