@article { author = {Mohammadi, A and Mehdizadeh, A R}, title = {Deep Brain Stimulation and Gene Expression Alterations in Parkinson’s Disease}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {}, keywords = {}, url = {https://jbpe.sums.ac.ir/article_43216.html}, eprint = {https://jbpe.sums.ac.ir/article_43216_940504a9b0a53f2d49b417c5f9ab0039.pdf} } @article { author = {Bahreyni Toosi, M T and Mohammadian, N and Ghorbani, M and Khorshidi, F and Akbari, F and Knaup, C}, title = {Skin Dosimetry in Radiotherapy of Breast Cancer: a Comparison between EBT and EBT3 Radiochromic Films}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Objective: Radiochromic EBT3 film is a later generation of radiochromic films. The aim of this study is to compare EBT and EBT3 radiochromic films in radiotherapy fields of breast cancer.Methods: A RANDO phantom was irradiated by a 6 MV Siemens Primus linac with medial and lateral fields of radiotherapy of breast cancer. Dosimetry was performed in various points in the fields using EBT and EBT3 films. Films were scanned by a Microtek color scanner. Dose values from two films in corresponding points were compared.Results: In the investigation of calibration, net optical density (NOD) of EBT radiochromic is more than the EBT3 radiochromic film. The highest percentage difference between NODs of two films is related to 0.75 Gy and equals to 14.19%. The lowest value is related to 0.2 Gy dose and is equal to 3.31%. The highest percentage difference between two films on the RANDO phantom in breast cancer fields is 13.51% and the minimum value is equal to 0.33%.Conclusion: From the comparison between the two films, most of the points show differences in dose in the measurements in fields of breast cancer radiotherapy. These differences are attributed to the thickness of the active layers, the overall thickness of the films, and the difference in the calibration fitted functions. The advantage of EBT film over EBT3 is a higher sensitivity; on the other hand EBT3 film allows to use its both sides in the scanning process and it is a new version of this film type. }, keywords = {Film dosimetry,EBT radiochromic film,EBT3 radiochromic film,Breast cancer}, url = {https://jbpe.sums.ac.ir/article_43217.html}, eprint = {https://jbpe.sums.ac.ir/article_43217_ebf9a34a53a0956a497d032c6a42c9c2.pdf} } @article { author = {Khoshdel-Navi, D and Shabestani-Monfared, A and Deevband, M R and Abdi, R and Nabahati, M}, title = {Local-Reference Patient Dose Evaluation in Conventional Radiography Examinations in Mazandaran, Iran}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Background:The most efficient application of ionizing radiation is serving medical purposes and using this radiation has caused people to learn that artificial sources of radiation exposure among these resources can be of highest exposure rate.  Objective: The present study is aimed at initially establishing a baseline for local-reference dose level in Mazandaran, Iran in 12 projections of the most conventional x-ray examination.          Methods: In this study, 13 public hospitals in Mazandaran province were selected for review and required data collected for ten adult patients with mean weight of 70±10kg in each projection. Then, information of each center was separately analyzed. Next, in order to measure x-ray output tube, the dosimeter RTI model Barracuda calibrated has been applied for measuring air karma within energy rage of 40-150kvp. ESAK and ESD parameters, usually used for monitoring DRL in conventional radiography, were calculated. Results: Mean ESDs in this study has been obtained to 1.47±0.98 for skull (PA/AP), 1.01±0.79 for skull (LAT), 0.67±0.38 for cervical spine (AP), 0.79±0.37 for cervical (LAT), 0.49±0.38 for chest (PA/AP), 1.06±0.44 for chest (LAT), 2.15±0.73 for thoracic spine (AP), 3±0.87 for thoracic spine (LAT), 2.81 ±0.82 for lumbar spine (AP), 4.28±0.78 for lumbar (LAT), 2.07±1.17 for abdomen and 1.90±0.99 for pelvis, respectively. The ESDs calculated for chest examination in both projections, PA and LAT are more than values recommended by the UK (2000), Brazil and Slovenia. Conclusion:The present study has determined wide variations in radiation dose of x-ray examinations among hospitals in Mazandaran, Iran. In order to reduce skin dose, an optimization procedure should be considered. Application of a reference dose (DRL) could be a practical method for this purpose. The role of optimization of radiography parameters for reducing patient dose is a significant issue. Through optimizing parameters, it would be possible to preserve image quality while reduction of patient dose.}, keywords = {Conventional Radiography,Dosimeter,Patient Dose,Mazandaran,ESAK,ESD}, url = {https://jbpe.sums.ac.ir/article_43218.html}, eprint = {https://jbpe.sums.ac.ir/article_43218_2347b8fc65a6aae656087b9c46a1aab9.pdf} } @article { author = {Ghazikhanlou-sani, K and Firoozabadi, SMP and Agha-ghazvini, L and Mahmoodzadeh, H}, title = {Evaluation of Soft Tissue Sarcoma Tumors Electrical Conductivity Anisotropy Using Diffusion Tensor Imaging for Numerical Modeling on Electroporation}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Introduction: There is many ways to assessing the electrical conductivity anisotropyof a tumor. Applying the values of tissue electrical conductivity anisotropyis crucial in numerical modeling of the electric and thermal field distribution in electroporationtreatments. This study aims to calculate the tissues electrical conductivityanisotropy in patients with sarcoma tumors using diffusion tensor imaging technique.Materials and Method: A total of 3 subjects were involved in this study. Allof patients had clinically apparent sarcoma tumors at the extremities. The T1, T2 andDTI images were performed using a 3-Tesla multi-coil, multi-channel MRI system.The fractional anisotropy (FA) maps were performed using the FSL (FMRI softwarelibrary) software regarding the DTI images. The 3D matrix of the FA maps of each area(tumor, normal soft tissue and bone/s) was reconstructed and the anisotropy matrixwas calculated regarding to the FA values.Result: The mean FA values in direction of main axis in sarcoma tumors wereranged between 0.475–0.690. With assumption of isotropy of the electrical conductivity,the FA value of electrical conductivity at each X, Y and Z coordinate axes wouldbe equal to 0.577. The gathered results showed that there is a mean error band of 20%in electrical conductivity, if the electrical conductivity anisotropy not concluded at thecalculations. The comparison of FA values showed that there is a significant statisticaldifference between the mean FA value of tumor and normal soft tissues (P<0.05).Conclusion: DTI is a feasible technique for the assessment of electrical conductivityanisotropy of tissues. It is crucial to quantify the electrical conductivity anisotropydata of tissues for numerical modeling of electroporation treatments.}, keywords = {Diffusion tensor imaging,Electrical conductivity,Anisotropy,Sarcoma tumors}, url = {https://jbpe.sums.ac.ir/article_43219.html}, eprint = {https://jbpe.sums.ac.ir/article_43219_fcd4de8163dbaea5a06dfa1d8f550dca.pdf} } @article { author = {Rezaee, Kh and Azizi, E and Haddadnia, J}, title = {Optimized Seizure Detection Algorithm: A Fast Approach for Onset of Epileptic in EEG Signals Using GT Discriminant Analysis and K-NN Classifier}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Background: Epilepsy is a severe disorder of the central nervous system that predisposes the person to recurrent seizures. Fifty million people worldwide suffer from epilepsy; after Alzheimer’s and stroke, it is the third widespread nervous disorder.Objective: In this paper, an algorithm to detect the onset of epileptic seizures based on the analysis of brain electrical signals (EEG) has been proposed. 844 hours of EEG were recorded form 23 pediatric patients consecutively with 163 occurrences of seizures. Signals had been collected from Children’s Hospital Boston with a sampling frequency of 256 Hz through 18 channels in order to assess epilepsy surgery. By selecting effective features from seizure and non-seizure signals of each individual and putting them into two categories, the proposed algorithm detects the onset of seizures quickly and with high sensitivity.Method: In this algorithm, L-sec epochs of signals are displayed in form of a thirdorder tensor in spatial, spectral and temporal spaces by applying wavelet transform. Then, after applying general tensor discriminant analysis (GTDA) on tensors and calculating mapping matrix, feature vectors are extracted. GTDA increases the sensitivity of the algorithm by storing data without deleting them. Finally, K-Nearest neighbors (KNN) is used to classify the selected features.Results: The results of simulating algorithm on algorithm standard dataset shows that the algorithm is capable of detecting 98 percent of seizures with an average delay of 4.7 seconds and the average error rate detection of three errors in 24 hours.Conclusion: Today, the lack of an automated system to detect or predict the seizure onset is strongly felt.}, keywords = {EEG Signals,Epileptic Seizure,General Tensor Discriminant Analysis (GTDA),K-NN,Wavelet Transform}, url = {https://jbpe.sums.ac.ir/article_43220.html}, eprint = {https://jbpe.sums.ac.ir/article_43220_2e381a09b3ad274093f39d94983102b9.pdf} } @article { author = {Javadpour, A and Mohammadi, A}, title = {Improving Brain Magnetic Resonance Image (MRI) Segmentation via a Novel Algorithm based on Genetic and Regional Growth}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Background: Regarding the importance of right diagnosis in medical applications, various methods have been exploited for processing medical images solar. The method of segmentation is used to analyze anal to miscall structures in medical imaging.Objective: This study describes a new method for brain Magnetic Resonance Image (MRI) segmentation via a novel algorithm based on genetic and regional growth.Methods: Among medical imaging methods, brains MRI segmentation is important due to high contrast of non-intrusive soft tissue and high spatial resolution. Size variations of brain tissues are often accompanied by various diseases such as Alzheimer’s disease. As our knowledge about the relation between various brain diseases and deviation of brain anatomy increases, MRI segmentation is exploited as the first step in early diagnosis. In this paper, regional growth method and auto-mate selection of initial points by genetic algorithm is used to introduce a new method for MRI segmentation. Primary pixels and similarity criterion are automatically by genetic algorithms to maximize the accuracy and validity in image segmentation.Results: By using genetic algorithms and defining the fixed function of image segmentation, the initial points for the algorithm were found. The proposed algorithms are applied to the images and results are manually selected by regional growth in which the initial points were compared. The results showed that the proposed algorithm could reduce segmentation error effectively.Conclusion: The study concluded that the proposed algorithm could reduce segmentation error effectively and help us to diagnose brain diseases.  }, keywords = {Brain Magnetic Resonance Image,Segmentation,Regional Growth,genetic algorithm}, url = {https://jbpe.sums.ac.ir/article_43221.html}, eprint = {https://jbpe.sums.ac.ir/article_43221_6b9561e4bbe6d151da3b22ae05b08861.pdf} } @article { author = {Ashrafi, H and Shariyat, M}, title = {A Nano-indentation Identification Technique for Viscoelastic Constitutive Characteristics of Periodontal Ligaments}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Introduction: Nano-indentation has recently been employed as a powerful tool for determining the mechanical properties of biological tissues on nano and micro scales. A majority of soft biological tissues such as ligaments and tendons exhibit viscoelastic or time-dependent behaviors. The constitutive characterization of soft tissues is among very important subjects in clinical medicine and especially, biomechanics fields. Periodontal ligament plays an important role in initiating tooth movement when loads are applied to teeth with orthodontic appliances. It is also the most accessible ligament in human body as it can be directly manipulated without any surgical intervention. From a mechanical point of view, this ligament can be considered as a thin interface made by a solid phase, consisting mainly of collagen fibers, which is immersed into a so-called ground substance. However, the viscoelastic constitutive effects of biological tissues are seldom considered rigorous during Nano-indentation tests. Methods: In the present paper, a mathematical contact approach is developed to enable determining creep compliance and relaxation modulus of distinct periodontal ligaments, using constant–rate indentation and loading time histories, respectively. An adequate curve-fitting method is presented to determine these characteristics based on the Nano-indentation of rigid Berkovich tips. Generalized Voigt-Kelvin and Wiechert models are used to model constitutive equations of periodontal ligaments, in which the relaxation and creep functions are represented by series of decaying exponential functions of time. Results: Time-dependent creep compliance and relaxation function have been obtained for tissue specimens of periodontal ligaments. Conclusion: To improve accuracy, relaxation and creep moduli are measured from two tests separately. Stress relaxation effects appear more rapidly than creep in the periodontal ligaments.}, keywords = {Nano-indentation,Creep and Relaxation,Periodontal Ligaments,Viscoelastic Biological Tissues,Contact Mechanics}, url = {https://jbpe.sums.ac.ir/article_43222.html}, eprint = {https://jbpe.sums.ac.ir/article_43222_44fa096720f58c5b72d7c57ebe43f74c.pdf} } @article { author = {Rismanchi, M}, title = {Pulsed Intra-Arterial Drug Injection during Diastolic Phase of Cardiac Function Increases Drug Efficacy by Enhancing Pharmacological Exposure of Targeted Tissues}, journal = {Journal of Biomedical Physics and Engineering}, volume = {6}, number = {2}, pages = {-}, year = {2016}, publisher = {Shiraz University of Medical Sciences}, issn = {2251-7200}, eissn = {2251-7200}, doi = {}, abstract = {Diastolic phase of cardiac function is associated with lower arterial flow and hence higher concentration of intra arterially injected drug is achieved at the site of injection. It is herein postulated that drugs show higher efficacy when injected during the diastolic phase of cardiac function. It is also postulated that this benefit cannot be achieved when the drug is injected with higher rates thus producing the same high concentration at the site of injection. Pulsed intra arterial injection also benefits from the delayed therapeutic effect of the decaying drug before the next shot of injection resaturates the targeted tissue. Altogether, it is estimated that diastolic time-locked pulsed intra arterial injection will increase the drug efficacy up to 1.9 times the efficacy of injected drug with conventional methods. This is significant for drugs with limited dose of administration due to their disastrous side effects like tissue plasminogen activator or chemotherapeutic drugs. }, keywords = {Area Under the Curve,Diastolic Phase,Drug Exposure,Intra-Arterial Drug Injection,Pulsatile Injection,t-PA}, url = {https://jbpe.sums.ac.ir/article_43215.html}, eprint = {https://jbpe.sums.ac.ir/article_43215_05920baad38ccd4e12a3d4fb2aa8f6d5.pdf} }