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Abstract Planning maintenance of medium voltage overhead lines is one of the most important issues in the studies on power distribution network, which will prevent and reduce unwanted interruption. In this paper, long‐term maintenance of medium voltage networks was planned by multi‐objective function, including an extended mixed‐integer linear model to optimize costs, energy not supplied (ENS), and average interruption duration index (SAIDI). In addition, the uncertainty about the annual growth rate of the load, the increase in the cost of goods and services and the increase in the selling price of energy as well as various constraints are all included in the desired objective function, which is one of the main innovations of this paper compared to other published studies. To apply the uncertainties, information gap decision theory (IGDT) has been used, and to solve the objective functions, LP‐Metric method has been used. The proposed method was implemented on the standard 11‐bus RBTS network by MATLAB and GAMS. The results showed that three different long‐term maintenance plans proposed here lead to the optimization of the annual maintenance costs of network, reduction in ENS and interruption, and increase in the reliability of the network based on the uncertainty of each feeder.

We consider a full-duplex (FD) cellular network, where uplink (UL) and downlink (DL) transmissions are performed at the same time over the same frequency band by using the non-orthogonal multiple-access (NOMA) technique. By leveraging the zero-forcing (ZF) beamforming at the FD multi-antenna base station, self-interference is mitigated, and the instantaneous sum rate of the system is maximized. More specifically, we propose two ZF-based beamforming designs at the base station, namely receive ZF (RZF) and transmit ZF (TZF) scheme, which respectively utilize the receive and transmit antennas at the BS to cancel out the SI at the BS. We derive closed-form expression for the outage probability of the NOMA near and far users as a function of different system parameters. Finally, we examine the accuracy of the results by using extensive simulation results. Our numerical results show that for both TZF and RZF scheme, increasing the number of transmit and receive antenna is beneficial to improve the outage performance of the DL near user, while increasing the number of transmit and receive antenna significantly improve the outage performance of the DL far user with RZF scheme.

Multistage amplifiers have become appropriate choices for high-speed electronics and data conversion. Because of the large number of high-impedance nodes, frequency compensation has become the biggest challenge in the design of multistage amplifiers. The new compensation technique in this study uses two differential stages to organize feedforward and feedback paths. Five Miller loops and a 500-pF load capacitor are driven by just two tiny compensating capacitors, each with a capacitance of less than 10 pF. The symbolic transfer function is calculated to estimate the circuit dynamics and HSPICE and TSMC 0.18 μm. CMOS technology is used to simulate the proposed five-stage amplifier. A straightforward iterative approach is also used to optimize the circuit parameters given a known cost function. According to simulation and mathematical results, the proposed structure has a DC gain of 190 dB, a gain bandwidth product of 15 MHz, a phase margin of 89 dgree, and a power dissipation of 590 μW.

The flow and heat transfer of a novel type of functional phase change nanofluids, nano-‎encapsulated phase change suspensions, is investigated in the present study using a deep neural ‎networks framework. A deep neural network was used to learn the natural convection flow and ‎heat transfer of the phase change nanofluid in an enclosure. A dataset of flow and heat transfer ‎samples containing 3290 samples of the flow field and temperature distributions was used to ‎train the deep neural network. The design variables were fusion temperature of nanoparticles, ‎Stefan number, and Rayleigh number. The results showed that the proposed combination of a ‎feed-forward neural network and a convolutional neural network as a deep neural network could ‎robustly learn the complex physics of flow and heat transfer of phase change nanofluids. The ‎trained neural network could estimate the flow and heat transfer without iterative and costly ‎numerical computations. The present neural network framework is a promising tool for the design ‎and prediction of complex physical systems‎.

Background: The goal of this study was to make a dosimetric comparison between the absorbed dose distribution of the prostate and the organ at risk (OAR) using two different approaches: three-dimensional conformal radiotherapy (3D-CRT) and Intensity-modulated radiotherapy (IMRT), assesed via treatment planning system (TPS) and thermoluminescence dosimetry (TLD). Methods: In this study, 35 patients with prostate cancer undergoing radiation therapy at Milad Hospital in Isfahan were included. Prostate as target and rectum, bladder and femoral head as healthy organ at risk (OAR) were contoured according to Radiation Therapy Oncology Group (RTOG) criteria. Two separate dosimetry programs IMRT and 3D-CRT have been developed for each patient in order to evaluate the dosimetric status of both methods comparatively. These results were then compared with those of the phantom. Findings: The doses to the bladder, rectum, and femoral head were 50.3, 58.6, and 16.4 in IMRT and 59.6, 68.8, and 34.8 in 3D-CRT, respectively. The dose measured by TLD in all organs in the phantom was higher than the dose calculated by TPS software in the phantom. Conclusion: The IMRT method is a better method than 3D-CRT due to better coverage of the target volume and reduction of the cumulative dose of organs at risk (OAR). The dose measured by TLDs was higher than the dose calculated by the treatment planning system, which may be due to the fact that the treatment planning system does not calculate the share of scattered radiation in the absorbed dose of organs.

This study presents a novel multilayer structure of parallel coupled-line bandpass filtercentered at 2.42 GHz with a fractional bandwidth value of approximately 19.4%. The designed filter can suppress harmonics with an appropriate frequency response by incorporating different techniques based on the multilayer technique. A combination of different techniques such as radial microstrip stubs and defected ground structure (DGS) and defected microstrip structure techniques are employed to suppress harmonics up to 5f0. These techniques are used in two layers to suppress up to 5f0. In addition, in this study, the effects of different parameters, such as the width of slot-line DGS, the angle of diagonal line slots in the upper layer, and the air gap between the two layers on the filter performance, are investigated. To verify the correct circuit operation, the designed filter is implemented and tested. The measurement results of the proposed filter are compared with the simulation results.

Background: Recent advances in molecular imaging of prostate cancer, including diffusion-weighted imaging, have led to improved cancer screening methods. The Ki-67 biomarker plays an important role in the prevention, diagnosis, and treatment of prostate cancer. The purpose of this study was to investigate the correlation between apparent diffusion coefficient of diffusion weight imaging with Ki-67 factor. Methods: This was a cross-sectional study on 36 patients with prostate cancer, who underwent radical prostatectomy. All patients underwent diffusion weight imaging before surgery, and Ki-67 factor was evaluated by immunohistochemistry (IHC). Statistical analysis was performed to investigate the relationship between apparent diffusion coefficient and Ki-67 factor using SPSS software. Findings: The ki-67 factor was inversely correlated with the apparent diffusion coefficient in peripheral (P < 0.001) and interstitial zone (P = 0.030). Nevertheless, it had a direct relationship with the degree of tumor malignancy (P = 0.035). Conclusion: Apparent diffusion coefficient can be used as a noninvasive criterion for assessing ki-67 and prostate cancer tumor invasion, which is important in diagnosing, grading, and predicting the survival of patients with prostate cancer.

Cooperative communication that enables the use of relays between a base station (BS) and end users is an effective technique against fading to improve network performance, especially in increasing spectral efficiency (SE) and network coverage. However, systems that use cooperative communication have weaknesses in the structure, such as resistance to latency and an increase in the bandwidth of substitute users (SU), which can be improved by optimizing the relay selection method effectively. The system due to insufficient spacing between antennas and insufficient scattering in the channel has spatially faded that leads to spatial correlation. We use Kronecker statistical model correlated multiantenna channels to implement detection techniques and eliminate interference in cooperative communication. The validity of the Kronecker model lies in the fact that correlation coefficients of transmission are independent of the receiving antennas. In other words, the spatial correlation model separates both ends of the communication link. Therefore, using the minimum mean-squared-error (MMSE) technique, we have removed the need for optimal elimination of interference between SU and relay service provider or primary user (PU). Regardless of BS performance, the scope of this work is restricted to the layer after the BS in the interaction between the service providers and substitute users. The primary purpose of the presented method is to improve the spectral gain through the elimination of interference. Simulation results show about 10% of SE improvement along with considerable traffic gain.

In this paper, the precoders capable of maximizing the weighted sum rate (WSR) for multicell scenarios under power budget constraint conditions per cell were considered based on the MIMO system performance. This rate is strongly affected by intracellular interference, so we recommend using coordinated beam forming (CBF). If the number of user equipment provided per cell is small enough to the number of transmit antennas, simple linear beamformers, such as matched filter (MF), achieve higher performance rates. In general cases, two algorithms meet the best performance in terms of the total achievable rate; these are KG (Kim Giannakis) and WSMSE (Weighted Sum Minimum Squared Error) algorithms. In the KG method, the objective function of the sum rate is suggested to be divided into two functions, one function for the desired user rate and the other for the sum rate of the remaining users. In the WSMSE algorithm, maximizing the sum rate is solved by redefining it as the problem of minimizing the MSE (Mean Square Error) function. These functions are convex and nonconvex functions, respectively. In the proposed method, the WSMSEs were modified to reduce the complexity and calculations to provide optimal performance in beamforming.

Background: The purpose of this study was to evaluate the effect of shields in imposed radiation dose to gonads in anterior-posterior (AP) and lateral views of lumbosacral radiography using digital radiography (DR) and computerized radiography (CR) methods. Materials and Methods: Sixty patients who were suspected to AP and lateral view of lumbosacral radiography were included in this study. The patients were exposed with and without shields which have 0.25 mm thickness. This study also compared the imposed dose to gonads for one and two plates of shields with none shields situation. Measurement of the radiation dose was performed using thermo luminescence dosimeters on the surface of the gonads. Furthermore, the absolute and excess relative risk (ERR) of biological abnormalities was estimated in the above-mentioned method using the BEIR VII model. Results: The mean dose of the DR method (10.14 ± 0.27) for the AP view was significantly lower than CR (32.43 ± 0.17) with and without shields. In addition, the imposed dose to gonads in the lateral view of DR (6.41 ± 0.47) was lower compared to CR (9.38 ± 0.14). Furthermore, the mean imposed dose to gonads for one and two pate shields of DR was lower than CR. Moreover, the excess relative risk to gonads in the AP for DR was lower compared to CR in all mentioned situations. Conclusion: Lumbosacral radiography is suggested to be performed by DR systems, due to the lower imposed dose and ERR to the gonads. Moreover, using shields may lead to decrease of scatter rays and also ERR of the gonads.

This paper proposes a full adder with minimum power consumption and lowloss with a central frequency of 1550nm using plasmonic Metal-Insulator-Metal (MIM)waveguide structure and rectangular cavity resonator. This full adder operates based onXOR and AND logic gates. In this full adder, the resonant wave composition of the firstand second modes has been used and we have obtained a high transmission coefficientin the states in which the output must be active. This full adder uses the AND and XORlogic gates to be designed with three inputs, which results in the design of a full adderwith lower complexity, lower cost and fewer losses than Other full adders in whichAND and XOR logic gates are combined to be designed with two inputs. The relatedsimulations were performed by FDTD. The obtained results presented a performancesimilar to the predicted models, while considering approximations with theoreticalrelations.

Background: The development of pulmonary complications after breast radiotherapy is still controversial. These complications might result in temporary or permanent damage to the lung. The aim of this study was to evaluate changes in the lung volume parameters (LVP) and to assess their relation with mean dose and the percentage of the lung receiving 20 Gy (V20) in the upper and lower lobes of the lung. Methods: Twenty three patients with breast cancer who underwent locoregional radiotherapy were selected. Six thermoluminescence dosimeters (TLDs) were distributed uniformly throughout the chest phantom to assess the accuracy of lung dose was calculated using treatment planning system (TPS). Body plethysmography was performed before, and 3 and 6 months after radiotherapy. Findings: Changes in LVP showed a decrease 3 months, and a slight improvement 6 months after radiotherapy. The mean percentage decrease in LVP was 0.64% and 0.34%for each Gy increase in mean lung dose (MLD) and for each percentage increase of V20, respectively. There was no significant correlation between changes in LVP with respect to age and concurrent hormonal therapy. The minimum and maximum calculation errors of the TPS were 1.8% and 4.2%, respectively. Conclusion: This study showed that changes in LVP, 3 and 6 months after radiotherapy did not cause pulmonary disease, and the TPS dose distribution was reasonably accurate.

Los circuitos CMOS de Domino se utilizan ampliamente en sistemas integrados de gran escala (VLSI) de alto rendimiento. La topología de los circuitos dominó para operación de alta velocidad, menor consumo de energía y robustez es de gran importancia en el diseño de sistemas digitales. El presente artículo propone un circuito sumador completo de baja potencia y alta velocidad, que utiliza una nueva familia lógica de dominó CMOS basada en elementos de unión de túnel magnético (UTM) y memristor en la técnica de entrada de difusión de puerta (GDI). En comparación con un circuito lógico CMOS estático, un circuito lógico dinámico es importante ya que proporciona una mayor velocidad y requiere menos transistores. En comparación con los circuitos propuestos recientemente para estilos lógicos dinámicos, las características del circuito propuesto son un consumo de energía dinámica muy bajo y menos retardo. El problema con los circuitos dinámicos es la falta de una salida estable en diferentes momentos, mientras que el circuito propuesto conserva el valor de salida utilizando elementos de memoria como UTM y memristor durante el ciclo de reloj. La técnica propuesta muestra un consumo máximo de energía de 0,317 µW en sumadores completos basados en MTJ/Memristor. Además, la técnica propuesta muestra un retraso máximo de 0,35 ns. Se simula el sumador completo propuesto, y su disipación de potencia y rendimiento se analizan utilizando HSPICE en tecnología CMOS estándar de 7 nm.

مقدمه: هدف از انجام این مطالعه، ارزیابی دز تحمیلی و همچنین، مقادیر احتمال بروز عوارض در بافت سالم (Normal tissue complication probability یا NTCP) قلب و ریه ناشی از تابش غدد فوق ترقوه‌ای با میدان‌های قدامی- خلفی (Anterior-posterior یا AP) و موازی مقابل هم (Parallel opposed fields یا POFs) هنگام درمان بیماران ماستکتومی شده در روش مماسی بود. روش‌ها: از یک فانتوم قفسه‌ی سینه، تصاویر Computed tomography scan (CT scan) گرفته شد. سپس، با استفاده از سیستم طراحی درمان (Treatment planning system یا TPS) TiGRT، روش‌های AP و POFs اجرا و با استفاده از Dose-volume histogram (DVH) حاصل مقادیر NTCP تخمین زده شد. سپس، مطابق با طراحی درمان انجام شده، فانتوم با استفاده از فوتون‌های 15 و 6 مگاولت دستگاه شتاب دهنده‌ی خطی Siemens primus تحت تابش قرار گرفت و دز قلب و ریه با استفاده از دزیمترهای ترمولومینسانس (Thermoluminescent dosimeter یا TLD) در فانتوم اندازه‌گیری شدند. یافته‌ها: دز میانگین قلب و ریه در روش مماسی با یک میدان AP (به ترتیب 17/3 ± 73/28 و 84/2 ± 42/35 درصد) به طور معنی‌داری کمتر از روش مماسی با دو میدان POFs (به ترتیب 77/3 ± 41/30 و 35/2 ± 36/49 درصد) بود (به ترتیب 078/0 = P و 045/0 = P) بود. همچنین، مقادیر NTCP ریه مجاور و قلب در طرح مماسی با میدان AP (به ترتیب 3 و 4 درصد) کمتر از طرح مماسی با POFs (به ترتیب 6 و 4 درصد) بودند. نتیجه‌گیری: به نظر می‌رسد تابش غدد فوق ترقوه‌ای با یک میدان AP، به دلیل دز و همچنین، NTCP کمتر به قلب و ریه، در مقایسه با دو میدان POFs، روش مناسب‌تری برای درمان ماستکتومی باشد.

Background: The purpose of this study was to estimate the secondary cancer risk of thyroid in standard radiotherapy methods which are commonly used for breast cancer patients. Methods: A total of 64 breast cancer patients (their age range was around 50 years old) who referred to Seyed-Al-Shohada hospital (Isfahan, Iran) were included in this study. The radiotherapy of the mentioned patients was performed using 6-MV photon beams. Dose measurements were also done using thermoluminescent dosimeters. Calculation of the risk of developing secondary cancer in thyroid was done using the Biological Effects of Ionizing Radiation Committee VII and recommended quantity of the International Radiation Protection Commission, excess relative risk. Results: The mean radiation dose to thyroid for the tangential beams, tangential field with supraclavicular (SC) field, and also a tangential field with SC field in modified radical mastectomy (MRM) were 0.883 ± 0.472, 1.512 ± 0.365, and 1.587 ± 0.37, respectively. The risk of developing secondary thyroid cancer over a period of 5 years after breast cancer therapy in the tangential, tangential with a SC field, and also tangential beam with SC field in MRM were 9.974 ± 4.318, 17.891 ± 0.365, and 18.783 ± 4.384, respectively. The mean of the measured thyroid doses in patients treated with tangent fields was significantly lower than the patients under the irradiation of the tangent fields with SC field (P < 0.001). Conclusions: Using radiation protection equipment is suggested for breast cancer patients who treated with the studied radiotherapy methods.

Background: Calculation of dose distribution of electron beams within in homogeneities may be complex for some of treatment planning systems (TPS). The aim of this study was to investigate the calculation errors of targeted image-guided radiation therapy treatment planning systems (TiGRT TPS) for dose distribution of electron beams within lung. Methods: The computed tomography (CT) images of an anthropomorphic Rando phantom were imported on the treatment planning systems (TiGRT, Lina Tech, China). The direct 10 MeV electron plan was performed by the TiGRT treatment planning systems. According to the plan, the phantom was irradiated using 10 MeV electrons of Siemens Primus linac. Dose measurements were done using LiF (TLD-100) inside the lung of this phantom. Finally, the calculation of the treatment planning systems was compared to the dose measurements. Findings: The minimum (0.86%) and maximum (76.14%) calculation errors of the treatment planning systems were occurred on the chest wall-lung interface and at the end of lung, respectively. Conclusion: It considerably seems that the treatment planning systems may not be able to perform some of essential corrections for dose distribution of electrons within in homogeneities. In this study, the in- homogeneities included ribs and lung with low electron density. The calculation errors may be resulted from production of secondary beams and multi scattering of electrons (when the electrons incident to ribs), and also X-ray contamination of electron beams at the end of its path. Therefore, the calculation of the treatment planning systems for dose distribution of electron beams within the lung is not comfortable.

Background: Hodgkin lymphoma is one of the treatable malignant diseases. The incidence of secondary cancers, especially breast cancer, and cardiovascular diseases after radiotherapy doubles the importance of patient treatment plan. In this study, some comparisons were made between a variety of treatments by using photon energy of 6 and 18 Mv on the treated areas of neck and mediastinum. Methods: The contouring of all sensitive organs and treatment volumes were performed for 18 female patients with Hodgkin lymphoma involving neck and mediastinum, using TiGRT software. Then, comparison between different anterior-posterior (AP-PA) treatments with different weights of 6 and 18 Mv was done. Findings: Using 18-Mv photon with the same weight of the anterior and posterior than conventional 6-Mv photon caused 2-9% reduction in mean dose to breast, heart, and lungs. Although changing the normalization (isocenter) point from the center of tumor to sternal notch reduced the mean dose of the studied organs, 9-13% reduction in the mean dose of treatment volume did not meet the criterion (prescribed dose ± 105%). Conclusion: For women with Hodgkin lymphoma involving mediastinum and neck, using 18-Mv photon with the same weight of the anterior and posterior is more appropriate to meet the design criteria of treatment (coating suitable treatment volume of prescribed dose ± 105%). Changing isocenter point from the center of the tumor to sternal notch causes a more favorable result. The better uniformity of the dose distribution in treatment volume is achieved by using 18-Mv photon.

Background: After the surgery, radiation therapy is the most important part of treating brain tumors. Thyroid cancer is the second most prevalent malignancy, as a result of radiation therapy of head and neck. Therefore, in whole-brain radiation therapy, determining the absorption dose of thyroid and the risk of secondary thyroid cancer is important. The aim of this study was to calculate the absorption dose of thyroid and the risk of secondary thyroid cancer in whole-brain radiation therapy. Methods: The study included 50 patients undergoing whole-brain radiation therapy, with a mean age of less than 30 years old, in Isfahan Milad Hospital, Iran, using the ONCOR accelerator and 6-MV photon. Thermoluminescence dosimeter (TLD) was used to determine the dose received by the thyroid. Then, to calculate the risk of secondary thyroid cancer, the method of calculating risk in Biological Effected of Ionizing Radiation Committee (BEIR VII) report and the suggested quantity of International Commission on Radiological Protection (ICRP), which means excessive relative risk (ERR), were used. Findings: The calculated mean absorbed dose was 1.976 ± 0.611 and 2.213 ± 1.041 cGy in women and men, respectively. The mean risk of secondary cancer of the thyroid 3, 5, 10, 15 and 20 years after whole-brain radiation therapy was 4.601 ± 1.614, 1.559 ± 0.595, 0.176 ± 0.063, 0.050 ± 0.018, and 0.022 ± 0.009, in women and 3.253 ± 1.721, 1.150 ± 0.516, 0.125 ± 0.066, 0.035 ± 0.019, 0.016 ± 0.008 in men, respectively. The absorption dose of thyroid was not related to age (P = 0.743). Conclusion: The risk of secondary cancer of the thyroid is associated with sex and is 1.4 times more in women. In addition, by increasing the age after radiation the mean risk of induced cancer had a reducing behavior.

Background and Aims: Gender determination is an important step in identification. For gender determination, anthropometric evaluation is one of the main forensic evaluations. The aim of this study was the assessment of sphenoid sinus volume in order to determine sexual identity, using multi-slice CT images. Materials and Methods: For volumetric analysis, axial paranasal sinus CT scan with 3-mm slice thickness was used. For this study, 80 images (40 women and 40 men older than 18 years) were selected. For the assessment of sphenoid sinus volume, Digimizer software was used. The volume of sphenoid sinus was calculated using the following equation: v=∑ (area of each slice × thickness of each slice). Statistical analysis was performed by independent T-test. Results: The mean volume of sphenoid sinus was significantly greater in male gender (P=0.01).The assessed Cut off point was 9/35 cm3, showing that 63.4% of volume assessments greater than cut off point was supposed to be male and 64.1% of volumetry lesser than cut off point were female. Conclusion: According to the area under Roc curve (1.65%), sphenoid sinus volume is not an appropriate factor for differentiation of male and female from each other, which means the predictability of cut off point (9/35 cm3 ) is 65/1% close to reality.

Background: The aim of this study was to develop a nucleotide geometrical model of the circular mitochondrial DNA (mt-DNA) structure using Geant4-DNA toolkit to predict the radiation-induced damages such as single-strand breaks (SSB), double-strand breaks (DSB), and some other physical parameters. Methods: Our model covers the organization of a circular human mt genetic system. The current model includes all 16,659 base pairs of human mt-DNA. This new mt-DNA model has been preliminarily tested in this work by determining SSB and DSB DNA damage yields and site-hit probabilities due to the impact of proton particles. The accuracy of the geometry was determined by three-dimensional visualization in various ring element numbers. The hit locations were determined with respect to a reference coordinate system, and the corresponding base pairs were stored in the ROOT output file. Results: The coordinate determination according to the algorithm was consistent with the expected results. The output results contain the information about the energy transfers in the backbone region of the DNA double helix. The output file was analyzed by root analyzing tools. Estimation of SSBs and DSBs yielded similar results with the increment of incident particle linear energy transfer. In addition, these values seem to be consistent with the corresponding experimental determinations. Conclusions: This model can be used in numerical simulations of mt-DNA radiation interactions to perform realistic evaluations of DNA-free radical reactions. This work will be extended to supercoiled conformation in the near future.

مقدمه: با توجه به این که در رادیولوژی دندانی، کاربرد Cone beam computed tomography (CBCT) رو به افزایش است و بخش‌های دارای این تجهیزات در حال رشد هستند، تعیین دز و ارزیابی خطرات پرتوهای یونیزان امری ضروری است. در این مطالعه، دز جذبی تیروئید، پاروتید و چشم‌ها در دو آزمون CBCT (فک بالا و پایین) و پانورامیک با دستگاه CRANEX® 3D در بیماران مقایسه شد. روش‌ها: برای هر بیمار 5 عدد Thermoluminescence dosimeter (TLD) به صورت یک جفت پشت پلک بالای هر چشم، یک جفت 2 سانتی‌متر جلوی غضروف کوچک قدامی گوش و یک عدد در قسمت میانی گردن مورد استفاده قرار گرفت. برای مقایسه‌ی دز جذبی اندام‌های مختلف در دو آزمون، میانگین دز جذبی محاسبه گردید. یافته‌ها: در آزمون پانورامیک، چشم راست با 002/0 ± 020/0 میلی‌گری، کمترین میانگین دز جذبی و پاروتید راست با 053/0 ± 283/0 میلی‌گری بیشترین میانگین دز جذبی را داشتند. در آزمون CBCT، بیشترین میانگین دز جذبی مربوط به پاروتید راست (780/0 ± 650/4 میلی‌گری) و کمترین آن مربوط به چشم چپ (040/0 ± 311/0 میلی‌گری) بود. میانگین دز جذبی چشم‌ها، تیروئید و غدد پاروتید در پانورامیک برابر با 003/0 ± 022/0، 002/0 ± 027/0 و 051/0 ± 270/0 میلی‌گری و در CBCT برابر 050/0 ± 330/0، 051/0 ± 389/0 و 740/0 ± 410/4 میلی‌گری به دست آمد. دز جذبی دو آزمون، برای تمام اعضا اختلاف معنی‌داری را نشان می‌دهد (001/0 > P). نتیجه‌گیری: به دلیل تابش وسیع‌تر (تابش مخروطی شکل) و شرایط تابش بالاتر در CBCT، دز جذبی تمام اعضا در این آزمون بیشتر از آزمون پانورامیک (بیش از 10 برابر) است.

مقدمه: بیماری هوچکین (Hodgkin’s disease) نوع خاصی از لنفوم یا سرطان می‌باشد که با رشد غیر طبیعی سلول‌ها در دستگاه لنفاوی همراه است. این مطالعه، جهت بررسی توزیع دز در طرح درمان‌های مختلف در زنان مبتلا به بیماری هوچکین انجام شد. به علت وجود اندام‌های حساس در این ناحیه و بروز بیماری‌ها و سرطان‌های ثانویه بعد از رادیوتراپی، بررسی طرح درمان‌های مختلف در این ناحیه حایز اهمیت است. روش‌ها: از اطلاعات Computed tomography scan (CT scan) 18 بیمار زن مبتلا به بیماری هوچکین با درگیری مدیاستن استفاده شد. در مرحله‌ی بعد، توسط نرم‌افزار طراحی درمان بیمارستان سیدالشهدای (ع) اصفهان، کانتورینگ تمام اندام‌های حساس داخل فیلد و حجم درمانی انجام گرفت. سپس، مقایسه‌هایی بین درمان رایج موازی- مخالف با انرژی 6 و 18 مگاولتاژ و تکنیک چهار میدان با وزن‌های مختلف صورت گرفت. یافته‌ها: ماکزیمم دز رسیده به پستان در تکنیک چهار فیلدی نسبت به تکنیک رایج دو فیلد مقابل، 33 درصد کاهش یافت. از طرفی، تکنیک چهار فیلدی دز میانگین رسیده به پستان را حدود 3 برابر افزایش می‌دهد. متوسط دز میانگین رسیده به حجم درمانی در تکنیک‌های دو فیلدی، 102-100 درصد و در تکنیک چهار فیلدی، 5/99 درصد بود. نتیجه‌گیری: برای زنان مبتلا به بیماری هوچکین با درگیری مدیاستن، استفاده از تکنیک دو فیلدی با فوتون 18 مگاولتاژ با وزن 5/1 از قدام و 5/0 از خلف، نسبت به فوتون 6 مگاولتاژ نتایج قابل قبول‌تری دارد و استفاده از تکنیک چهار فیلدی، منجر به کاهش V20 برای کل ریه و کاهش دز میانگین رسیده به مری،آئورت، نخاع و نیز V30 قلب می‌گردد.

مقدمه: امروزه، اثرات بیولوژیک و کاربردهای امواج فراصوت به خصوص در حضور نانوذرات به سرعت در حال گسترش است. در این پژوهش، به بررسی تأثیر تابش امواج فراصوت و نانوذرات نقره بر میزان مرگ سلول‌های MCF-7 پرداخته شد. روش‌ها: سلول‌های توموری MCF-7 کشت داده شد. سلول‌ها به 4 گروه تقسیم شدند. در گروه نانوذرات، سلول‌ها با غلظت‌های 50، 100 و 200 میکروگرم بر میلی‌لیتر از نانوذرات با ابعاد 20 نانومتر در محیط کشت تیمار شدند. در گروه تابش امواج فراصوت، سلول‌ها تحت تابش فراصوت با شدت 2 وات بر سانتی‌متر مربع به مدت 3 دقیقه قرار گرفتند. در گروه نانوذرات همراه تابش امواج فراصوت، ابتدا سلول‌ها با غلظت‌های مختلف از نانوذرات در محیط کشت تیمار شدند و بعد از گذشت 5 ساعت، تحت تابش فراصوت با همان مشخصات قرار گرفتند. در گروه شاهد، هیچ مداخله‌ای انجام نشد. سپس، درصد زنده ماندن سلول‌ها در هر چهار گروه با روش MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) در سه بازه‌ی زمانی 24، 48 و 72 ساعت تعیین گردید. یافته‌ها: درصد بقای سلول‌های 7-MCF در گروه فراصوت به همراه نانوذرات در غلظت‌های مختلف نسبت به گروه شاهد در هر سه بازه‌ی زمانی تفاوت معنی‌داری داشت (050/0 > P). در گروه نانوذرات نیز میزان بقای سلول‌ها با افزایش غلظت و گذشت زمان کاهش و تفاوت معنی‌داری نسبت به گروه شاهد داشت. نتیجه‌گیری: میزان سمیت نانوذرات نقره همراه با تابش فراصوت اثر افزایشی داشت؛ می‌توان چنین نتیجه گرفت که استفاده‌ی هم‌زمان از نانوذرات نقره و امواج فراصوت، سمیت سلولی و به دنبال آن مرگ سلولی را افزایش می‌دهد.

Introduction Application of quality control (QC) programs at diagnostic radiology departments is of great significance for optimization of image quality and reduction of patient dose. The main objective of this study was to perform QC tests on stationary radiographic X-ray machines, installed in 14 hospitals of Kerman province, Iran. Materials and Methods In this cross-sectional study, QC tests were performed on 28 conventional radiographic X-ray units in Kerman governmental hospitals, based on the protocols and criteria recommended by the Atomic Energy Organization of Iran (AEOI), using a calibrated Gammex QC kit. Each section of the QC kit incorporated different models. Results Based on the findings, kVp accuracy, kVp reproducibility, timer accuracy, timer reproducibility, exposure reproducibility, mA/timer linearity, and half-value layer were not within the acceptable limits in 25%, 4%, 29%, 18%, 11%, 12%, and 7% of the evaluated units (n=28), respectively. Conclusion As radiographic X-ray equipments in Kerman province are relatively old with a high workload, it is recommended that AEOI modify the current policies by changing the frequency of QC test implementation to at least once a year.

To improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with 99mTc-marked diphosphonates (99mTc-MDP) by two different methods of background correction in conjugate view method. This study involved 22 patients referring to the Nuclear Medicine Center of Shahid Chamran Hospital, Isfahan, Iran. After the injection of 99mTc-MDP, whole-body images from patients were acquired at 10, 60, 90, and 180 min. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Finally, the absorbed dose was calculated using the Medical Internal Radiation Dosimetry (MIRD) technique. The results of this study showed that the absorbed dose per unit of injected activity (rad/mCi) ± standard deviation for pelvis bone, bladder, and kidneys by Buijs method was 0.19 ± 0.05, 0.08 ± 0.01, and 0.03 ± 0.01 and by conventional method was 0.13 ± 0.04, 0.08 ± 0.01, and 0.024 ± 0.01, respectively. This showed that Buijs background correction method had a high accuracy compared to conventional method for the estimated absorbed dose of bone and kidneys whereas, for the bladder, its accuracy was low.

مقدمه: شیمی‌درمانی یکی از پرکاربردترین روش‌های درمان سرطان‌ها می‌باشد. مهم‌ترین مرحله‌ی درمان، انتخاب موثرترین دارو برای ایجاد بیش‌ترین اثر سمیت بر سلول‌های سرطانی است. دوستاکسول دارویی است که هنگام استفاده‌ی ترکیبی با رادیوتراپی می‌تواند اثرات درمانی چشم‌گیری نظیر متوقف کردن چرخه‌ی سلولی در فاز G2/M، که مرحله‌ای بسیار آسیب‌پذیر به تابش‌های یونیزان است، داشته باشد. مدت زمان اثردهی دارو با سلول یکی از عواملی است که اثر آن تا کنون در مطالعات سلولی این دارو به عنوان یک عامل متغیر مورد بررسی قرار نگرفته است. در این مطالعه‌ی تجربی، ما به بررسی تأثیر تفاوت زمان اثردهی داروی دوستاکسول در افزایش میزان مرگ سلول‌های سرطانی پستان رده‌ی 7-MCF در محیط برون‌تنی پرداختیم. روش‌ها: در این مطالعه، سلول‌ها را به سه گروه شاهد، 1 با مدت زمان اثردهی 5 ساعت و 2 با مدت زمان اثردهی 24 ساعت در غلظت‌های مختلف داروی دوستاکسل تقسیم کردیم. میزان حیات سلولی از طریق آزمون MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] در سه بازه‌ی زمانی 24، 48 و 72 ساعت بعد از آزمایش سنجیده شد. یافته‌ها: میزان مرگ سلولی، وابسته به غلظت دارو بود. در مقایسه بین دو گروه 1 و 2، کاهش معنی‌داری در حیات سلولی، به ویژه در غلظت‌های بالا مشاهده شد که نشان‌دهنده‌ی تأثیر مدت زمان اثردهی بود. نتیجه‌گیری: مطالعه‌ی ما اثبات کرد که مدت زمان اثردهی داروی دوستاکسول عاملی مهم در میزان مرگ سلولی است و هنگام کاربرد هم‌زمان دوستاکسل با رادیوتراپی در مطالعات سلولی، باید به عنوان یک عامل متغیر مورد نوجه قرار گیرد.

Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the fact that most of the antiproton deposited dose is resulted from high-LET nuclear fragments following pion interaction in surrounding nucleons, we reproduced depth dose curves of most probable energy range of pions and neutron particle using Geant4. We consider this work one of the steps to understand the origin of the error and finally verification of Geant4 for antiproton tracking. Geant4 toolkit version 9.4.6.p01 and Fluka version 2006.3 were used to reproduce the depth dose curves of 220 MeV pions (both negative and positive) and 70 MeV neutrons. The geometry applied in the simulations consist a 20 Χ 20 Χ 20 cm 3 water tank, similar to that used in CERN for antiproton relative dose measurements. Different physic lists including Quark-Gluon String Precompound (QGSP)_Binary Cascade (BIC)_HP, the recommended setting for hadron therapy, were used. In the case of pions, Geant4 resulted in at least 5% dose discrepancy between different physic lists at depth close to the entrance point. Even up to 15% discrepancy was found in some cases like QBBC compared to QGSP_BIC_HP. A significant difference was observed in dose profiles of different Geant4 physic list at small depths for a beam of pions. In the case of neutrons, large dose discrepancy was observed when LHEP or LHEP_EMV lists were applied. The magnitude of this dose discrepancy could be even 50% greater than the dose calculated by LHEP (or LHEP_EMV) at larger depths. We found that effect different Geant4 physic list in reproducing depth dose profile of the beam of pions was not negligible. Because the discrepancies were pronounced in smaller depth and also regarding the contribution of pions in deposited dose of a beam of antiproton, further investigation on choosing most suitable and accurate physic list for this purpose should be done. Furthermore, this study showed careful attention must be paid to choose the appropriate Geant4 physic list for neutron tracking depending to the applications criteria. We failed to find any agreement between results from Geant4 and Fluka to reproduce depth dose profile of pion with the energy range used in this study.

Background: This study aimed to investigate the effect of patient’s size on the distribution and amount of dose of computed tomography (CT) based on standard cylindrical polymethyl methacrylate (PMMA) phantoms. Methods: In this study, a two-dimensional film dosimetry method was represented via using radiographic films; the effect of patient’s size on the distribution and the amount of received dose was investigated using cylindrical phantoms with 10, 16, 24 and 32 cm diameters. The cylindrical phantoms were made of polymethyl methacrylate sheets. By proper calibration, two-dimensional distribution of the dose was measured using film dosimetry in these phantoms in a single axial rotation. Findings: The dose distribution in the cylindrical phantoms was not symmetric particularly in closer points to the surface. The received dose in the cross-section of phantom increased with beam width. The received dose in the central part of phantom decreased more than its surface by the increment of phantom diameter. Specially, using a cylindrical phantom with diameter of16 cm, the received dose in the central part of the phantom decreased to 65% of its surface dose; whereas this percentage for cylindrical phantoms with diameters of 24 and 32 cm was 45% and 35%, respectively. Conclusion: The dose distribution in the cross-section of the pediatric patients is more uniform. It is highly dependent on the couch attenuation and overscan, leading to asymmetry of the dose distribution. The received dose in the pediatric patients would be more than adults for the same mAs.

After proposing the idea of antiproton cancer treatment in 1984 many experiments were launched to investigate different aspects of physical and radiobiological properties of antiproton, which came from its annihilation reactions. One of these experiments has been done at the European Organization for Nuclear Research known as CERN using the antiproton decelerator. The ultimate goal of this experiment was to assess the dosimetric and radiobiological properties of beams of antiprotons in order to estimate the suitability of antiprotons for radiotherapy. One difficulty on this way was the unavailability of antiproton beam in CERN for a long time, so the verification of Monte Carlo codes to simulate antiproton depth dose could be useful. Among available simulation codes, Geant4 provides acceptable flexibility and extensibility, which progressively lead to the development of novel Geant4 applications in research domains, especially modeling the biological effects of ionizing radiation at the sub-cellular scale. In this study, the depth dose corresponding to CERN antiproton beam energy by Geant4 recruiting all the standard physics lists currently available and benchmarked for other use cases were calculated. Overall, none of the standard physics lists was able to draw the antiproton percentage depth dose. Although, with some models our results were promising, the Bragg peak level remained as the point of concern for our study. It is concluded that the Bertini model with high precision neutron tracking (QGSP_BERT_HP) is the best to match the experimental data though it is also the slowest model to simulate events among the physics lists.

Background: Living environment and applied building materials in dwellings contain various amounts of radioactive elements. Knowing about the distribution and the level of radiation in the environment is very important to evaluate the effects of radiation on the human. In this study, the level of radioactive nuclei in the granite was assessed according to the color of the stone. Methods: 13 different types of granite used in city of Isfahan (Iran) dwellings were selected, turned to powder, packaged in Marinli dishes and sealed accordingly. The International Atomic Energy Commission instructions were applied for sampling and all other steps of the survey. The dishes were kept for 5 weeks before spectroscopy, to obtain equivalent amount of uranium and thorium nuclides. Then, the gamma-spectroscopy of each sample was collected by HPGe (high purity germanium detector) for 12 hours and categorized based on its energy level. Finally, the special activity of the radiating nuclides in each sample was obtained. Measuring natural radioactivity, including nucleus radioactivity of 238U, 232Th, 40K based on Bq/kg unit, was done. The specific average radioactivity concentration of each radiating nuclei was evaluated, too. Findings: The reported special activities for 238U were less than malondialdehydc (MDA) level for green, 65.72 Bq/Kg for white, 57.26 Bq/kg for red, and 24.31 Bq/kg for black granites. The measured special activities for 232Th were 113.36, 84.31, and 34.28 Bq/kg, and less than MDA level for white, red, black and green granites, respectively. Besides, the measured special activities for 40K were 53.16, 525.82, 897.37, and 1243.28 Bq/kg for green, black, red, and white granites, respectively. Conclusion: White granite sample has the highest special activity for the three nuclides, 238U, 232Th, and 40K. Also, the lowest special activity for these nuclides was found in green stones and the red granite had an intermediate activity. Keywords: High-purity germanium detector (HPGe), Color, Granite, Gamma spectroscopy, Natural radionuclides

The Monte Carlo method is the most accurate method for simulation of radiation therapy equipment. The linear accelerators (linac) are currently the most widely used machines in radiation therapy centers. In this work, a Monte Carlo modeling of the Siemens ONCOR linear accelerator in 6 MV and 18 MV beams was performed. The results of simulation were validated by measurements in water by ionization chamber and extended dose range (EDR2) film in solid water. The linac′s X-ray particular are so sensitive to the properties of primary electron beam. Square field size of 10 cm Χ 10 cm produced by the jaws was compared with ionization chamber and film measurements. Head simulation was performed with BEAMnrc and dose calculation with DOSXYZnrc for film measurements and 3ddose file produced by DOSXYZnrc analyzed used homemade MATLAB program. At 6 MV, the agreement between dose calculated by Monte Carlo modeling and direct measurement was obtained to the least restrictive of 1%, even in the build-up region. At 18 MV, the agreement was obtained 1%, except for in the build-up region. In the build-up region, the difference was 1% at 6 MV and 2% at 18 MV. The mean difference between measurements and Monte Carlo simulation is very small in both of ONCOR X-ray energy. The results are highly accurate and can be used for many applications such as patient dose calculation in treatment planning and in studies that model this linac with small field size like intensity-modulated radiation therapy technique.

Background: One of the diagnostic methods for cardiovascular diseases, particularly coronary artery abnormalities, is imaging. Invention of computed tomography (CT) devices with a multi-detector row in recent years has created new capabilities in the field of imaging, especially cardiovascular imaging. CT coronary angiography is a new imaging technique which can be implemented with these devices. Despite many advantages, this method imposes high absorbed dose (total ionizing dose, TID) to patients. Therefore, assessing the imposed dose rate to patients is very necessary. We assessed the doses absorbed by different organs including skin, thyroid, and eyes in CT coronary angiography and compared them with the values in conventional angiography. Methods: In this study, doses absorbed by skin, thyroid, and eyes of 67 patients were assessed. The subjects referred to Alzahra and Sina Hospitals (Isfahan, Iran) for CT coronary angiography. Doses were calculated through practical measurements of point doses using thermoluminescence dosimeter (TLD). In order for dosimetry of each of the mentioned organs, we used a pair of TLD GR-200. The average value obtained from each pair of TLD was considered as the dose of the organ. Dosimeters were calibrated using a Co-60 source. After the imaging, the dose values were separately calculated for each organ. The values were then compared with corresponding values in conventional angiography. The used CT devices were a 64-row detector CT (Lightspeed VCT, U.S.) in Alzahra Hospital and a 64-cross-sectional device (Phillips) in Sina Hospital. Findings: The mean doses absorbed by skin, thyroid, and eyes in CT coronary angiography were 8.32 ± 1.73 cGy, 2.06 ± 1.68 cGy, and 0.3 ± 0.1.6 cGy, respectively. The corresponding values in conventional angiography were 6.64 ± 9.3 cGy, 0.15 ± 0.17 cGy, and 0.03 ± 0.03 cGy. There was a significant difference between the 2 imaging methods in doses absorbed by the organs (P < 0.001). Range of doses absorbed by the skin in CT and conventional coronary angiography were 5.15-12.22 cGy and 0.07-39.00 cGy, respectively. Conclusion: Since the skin is directly irradiated, it absorbed higher doses compared to the other 2 organs in both methods. There were evident and considerable changes in skin dose range in both methods and the range of skin dose in conventional angiography was much more than CT coronary angiography. Absorbed dose of organs in CT angiography was much higher than conventional angiography. Scanning parameters can significantly alter the absorbed dose rate. Therefore, technicians should acquire adequate trainings in this regard and utilize them practically.

Background: The purpose of this study was to assess the entrance surface dose (ESD) and effective doses (ED) in postmenopausal women using dual energy X-ray absorptiometry (DXA). It also tried to determine the correlations between ESD and ED and height, weight and body mass index (BMI). Methods: Thermo luminescent dosimeters (TLD-GR200) and abdominal CT scans were used for patient dosimetry. The correlation coefficients and regression analysis was applied for 43 postmenopausal women who referred to Seyed Alshohada Hospital in Isfahan. Findings: Pearson's correlation analysis showed that there was a significant correlation between ESD and BMI (r = 0.885; P < 0.001) and weight (r = 0745; P < 0.001). However, there was an indirect correlation between ESD and height (r = -0.258; P = 0.047). Pearson's correlation analysis also showed an indirect correlation between ED and BMI (r = -0.651; P < 0.001), height (r = -0.346; P < 0.001) and weight (r = -0.811; P < 0.001). Mean values of ED and ESD were respectively determined as 0.50 µSv (0.26-0.95) and 9.54 µSv (7.25-12.65) for the anterior posterior (AP) spine scans. Conclusion: Our results showed that the exposure in bone densitometry with a Norland XR-46 system was very low (0.50 µSv). In fact, these values were much lower than the average daily background in the UK (7 µSv).

Background: The aim of this study was radiobiological evaluation of different radiotherapy (RT) techniques, namely, combined photon-electron, two tangential photon beams, and electron therapy which are commonly used for treatment of mastectomy patients. Materials and Methods: The mentioned techniques were planned on the computed tomography (CT) images of a chest phantom, using TiGRT treatment planning system (TPS). The TPS dose calculations were verified using Thermo Luminescence dosimeters (TLD) measurements. Dose-volume histogram (DVH) of the plans was generated in the TPS, and also tumor control probability (TCP) and normal tissue complication probability (NTCP) values were calculated using DVH data for each technique. For TCP and NTCP modeling, Poisson Linear-Quadatric (PLQ) and Lyman-Kutcher-Burman (LKB) models were used, respectively. Results: The TCPs for the chest wall, internal mammary nodes, supraclavicular nodes, and axilla for the combined photon-electron was 90%, 90%, 90%, and 65%, respectively, which was higher compared to tangential beams (up to 11%, 11%, 5%, and 5%, respectively) and the electron therapy (up to 11%, 11%, 33%, and 23%, respectively) Whereas the NTCPs of the tangential beams for ipsilateral and contralateral lungs, heart, and chest wall–lung interface was 4%, 1%, 3%, and 5.6%, respectively. These NTCP values were considerably lower than electron therapy (up to 42%, 66%, and 40% and 30%, respectively) and combined photon-electron (up to 55%, 75%, 50%, and 20%, respectively) methods. Conclusion: Tangential beam is suggested for treating mastectomy patients, due to sufficient value of TCP, and also lower NTCP compared to the other techniques such as electron therapy and combined photon-electron.

Introduction : Nowadays, medical equipment is essential to provide health care services in hospitals. Since 20% of the hospitals costs are devoted to providing such equipment, an appropriate management is required to maintain it. In this study it is intended to investigate the maintenance management of medical equipment in hospitals. Methods and materials : it is a cross-sectional study. The population of the study consisted of 40 managers, nursing services menagers, the head of medical engineering or medical equipment unit in hospitals affiliated to Isfahan University of Medical Sciences. The data were collected by a questionnaire which was checked for its validity and reliability. Results : planning organization, coordination and management of maintaing the medical equipment had the following mean scores respectively : 62%, 44%, 54% and 42% . Conclusion : In order to improve the quality of medical equipment maintenance management, the required financial and human resources must be supplied. It seems essential to train a person as a medical equipment expert, to hold training courses for the hospital personnel to learn how to use this equipment and to provide a software for medical equipment maintenance management. Keywords : equipment and supplies – materials managemeat, hospital – hospitals – hospitals, university

Background: Following human radiation exposure in hospital or accidents, dose assessments are of prime importance in radiation accidents. These issues are of continuing importance with respect to socioeconomic policy relating to the industrial and medical uses of ionizing radiation, and also for risk assessment among people who are occupationally exposed to low and/or high linear energy transfer (LET) radiation, such as astronauts, pilots, stewardesses, nuclear power plant workers, and victims of radiation accidents. Materials and Methods: In this study, an assay for assessing radiation dose based on the induction of apoptosis in human T-lymphocytes was done to examine T-lymphocyte cells isolated from the fresh blood of 16volunteers, cultured and exposed to gamma rays. Radiation-induced apoptosis (RIA) was assessed by flow cytometric identification of cells displaying apoptosis-associated DNA condensation. Results: Dose-response experiments showed that at 2Gy dose level of radiotherapy programs, the RIA frequency was significantly above control. Apoptotic levels significantly depend on the dose of radiation rather than the donor. Conclusion: The results demonstrate the potential use of this assay as a biological indicator of radiation toxicity, optimizing patient dose in radiotherapy and biological dosimetry process.