2021 CiteScore: 0.5
Mohammad Reza Ay
The Journal of "Frontiers in Biomedical Technologies" is a peer-reviewed, multidisciplinary journal. It is a medium for researchers, engineers, scientists and other professionals in biomedical technologies to record publish and share ideas and research findings that serve to enhance the understanding of medical imaging methods and systems, Nano imaging and nanotechnology, surgical navigation, medical robotics, biomechanical and bioelectrical systems, stem cell technology, etc.
Introduction: Fatty liver is the most common chronic liver disease, and finding the appropriate method for detecting the problem is necessary. The current study aimed to quantity the liver steatosis using computed tomography (CT) and ultrasound images, as well as alanine aminotransferase (ALT) blood test.
Materials and methods: In this work, 163 non-alcoholic fatty liver disease (NAFLD) patients implemented CT and ultrasound images on their abdomen regions. The liver and spleen density were calculated using CT images (as the standard method), and then the patients were divided into mild, and moderate to severe groups. During the sonography, M-value histogram of the liver and right kidney was drawn and their ratio (liver/kidney) was considered as hepatorenal index (HRI). Mann-Whitney test were used to evaluate the relationships between HRI and ALT values.
Results: The mean and standard deviation of the liver density in CT scans were obtained 51±4 HU. The HRI had better performance (area under the curve, AUC: 0.94) compared to the ALT (AUC: 0.88) in determining of liver steatosis. In addition, there was a significant difference between the mild, and moderate to severe groups (P<0.001) in HRI and ALT values.
Conclusion: Based on the results, HRI is a good factor to distinguish between mild, and moderate to severe fatty liver. It is notable that HRI is reproducible and operator independent.
The process of MRI image registration is one of the important branches in MRI image analysis, which is a necessary preprocessing to the use of information in these images. The Clustered Adaptive Keypoint Elimination method-SIFT (CRKEM-SIFT) algorithm has recently been introduced to eliminate redundancies and upgrade the precision corresponding. The disadvantages of this algorithm are the high execution time and the number of incorrect correspondences. In this paper, to increase the accuracy and speed of MRI image registration, first, the CRKEM method is used on the SURF algorithm. Then, Spatial Relations Correspondence (SRC) and Alpha-Trimmed Spatial Relations Correspondence (ATSRC) methods are suggested to improve correspondences. These suggested methods, unlike conventional methods such as RANSAC, which only eliminates incorrect correspondences, in these suggested methods based on spatial relationships, detect incorrect correspondences and turn them into correct correspondences. Converting incorrect correspondences to correct ones can increase the number of correct correspondences and ultimately increase the precision correspondences. The simulation results confirm the suggested approaches' superiority on standard brain databases compared to classic methods in terms of Maximum error (MAE) and precision.
Purpose: Numerous studies have described the effect of Electromagnetic Fields (EMFs) in the promotion of Bone Marrow Stem Cell (BMSC) differentiation. We aimed to investigate the influence of frequency (10 and 100 Hz) and different pulse shapes (sine, rectangular, and triangular) of EMF on rats' BMSCs.
Materials and Methods: The BMSCs in 6 groups were exposed to EMF for 1 h/ 7 days. The BMSCs viability was estimated by the MTT test. The cresyl violet labeled the Nissl bodies, and the silver nitrate staining was done to evaluate the BMSCs nucleoli Ag Nucleolar Organizer Regions (AgNORs).
Results: The MTT test verified that EMF and pulse shape did not affect cell viability. In Nissl bodies staining most of the large neurons were related to the rectangular 10 Hz EMF group. The majority of the differentiated BMSCs were astrocytes, microglia, and oligodendrocyte in the triangular 100 Hz EMF group. Although the silver nitrate staining confirmed the effect of 10 Hz EMF, pulse shape alteration did not affect AgNOR parameters. In conclusion, we presented a low-magnetic flux density EMF (400 µT) to assess the responses of BMSCs nuclei.
Conclusion: The findings showed that BMSCs differentiation was frequency-dependent. Further investigations are recommended for recognizing the function of EMF on BMSCs.
Purpose: According to the side effects of invasive cancer treatments, Sonodynamic Therapy (SDT) as a noninvasive method for breast adenocarcinoma was considered. Sonosensitizer agents’ encapsulation can improve the accumulation of these drugs in the tumor tissue and reduce treatment side effects. Hence, mice breast adenocarcinoma SDT with Hematoporphyrin (HP) and HP-encapsulated Mesoporous Silica Nanoparticles (HP-MSNs) was carried out.
Materials and Methods: Ninety-six female breast adenocarcinoma grafted Balb/C mice were randomly divided into 16 groups (n = 6): control, sham, HP, HP-MSN, Ultrasound (US), SDT+HP, and SDT+HP-MSN groups. Sonosensitizer agents were injected intraperitoneally (2.5 or 5 mg/kg, 0.2 ml) 24h before an US radiation (1MHz, 1 or 2 W/cm2, 60 sec). The tumor growth parameters were evaluated 30 days after SDT.
Results: The inhibition ratio was enhanced by 23, 18, 18, and 16% relative to the control group in HP-MSN (5 mg/kg), HP-MSN (2.5 mg/kg) HP (5 mg/kg) and US (2 W/cm2) groups, respectively, at 18 days after the injection time; whereas, the analysis of findings revealed an antitumor effect in SDT with HP-MSN groups. The Tumor Growth Inhibition (TGI) percentages were 45, 42, and 42% for the SDT (2 W/cm2) + HP-MSN (5 mg/kg), SDT (1 W/cm2) + HP-MSN (5 mg/kg), and SDT (2 W/cm2) + HP (2.5 mg/kg) groups, respectively, on the 18th day post-injection, and T2 and T5 times were higher than that of control and sham groups (P<0.05). The estimated 44-day survival time in the Kaplan-Meier test was 95% in the SDT (2 W/ cm2) + HP-MSN (5 mg/kg) treated group, which had moderately differentiated cells in tumor grading.
Conclusion: Based on the findings, SDT with HP-encapsulated MSNs (5 mg/kg) has an antitumor effect on breast adenocarcinoma.
Purpose: The Boundary Element (BE) and Finite Element (FE) methods are widely used numerical techniques to solve the Electroencephalography (EEG) forward problem. However, the FE Method (FEM) has difficulty in simulating current dipoles due to singularity, and the BE method (BEM) cannot simulate inhomogeneous and anisotropic conductivity profiles. Recently, a hybrid BE-FE method has been proposed to benefit from the advantages of both BEM and FEM in solving the EEG forward problem. Generally, the type of mesh may significantly influence the results of numerical EEG forward solvers and should be carefully studied.
Materials and Methods: In this paper, the performance of the hybrid BE-FE method is compared with an approach of FEM (partial integration) using three types of meshes. The ground truth is the analytical EEG forward solutions obtained from inhomogeneous and isotropic/anisotropic four-layer spherical head models with dipoles of radial and tangential directions at four eccentricities.
Results: The minimum mean of Relative Difference Measure (RDM) obtained from Partial Integration (PI)-FEM is 0.0596 at 70% source eccentricity while by using the hybrid BE-FE method it is improved to 0.0251 at the same eccentricity. On the other hand, the maximum mean of MAG obtained from PI-FEM is 0.6216 at 50% source eccentricity while it is improved to 0.9734 at the same eccentricity.
Conclusion: The results show that the hybrid BE-FE method outperforms PI-FEM in solving the EEG forward problem using three types of meshes regarding RDM and MAG error criteria.
Purpose: Skyshine radiation dose equivalent dose rate is known as scattered radiation by the room above air to points at the ground level points outside the Linear Accelerator (LINAC) room. Our aim was to estimate skyshine around the LINAC-based radiotherapy by a 4MV LINAC photon beam.
Materials and Methods: Monte Carlo (MC) MCNP code calculation was conducted to skyshine at the control room, 60Co treatment room, physics, and simulator rooms. National Council on Radiation Protection and Measurements (NCRP) 151 was also used and it reported analytical formulation methods for photon beam calculation. A Flattering Filter (FF) equipped and Flattening Filter-Free (FFF) LINACs photon beams were derived and differences and agreements were discussed.
Results: The results showed high skyshine for FF equipped relative to FFF LINACs. This effect may be attributed to photon beam hardening by FF in the LINAC head and higher transmission through the ceiling shield and more presence of photons on the roof above the air. NCRP 151 method results were higher than MC simulated photon beam skyshine dose equivalent dose rate and it may be the cause of the inflexible analytical method in contrast to MC simulation. Finally, FFF and FF-equipped LINACs result in skyshine compared and they compared to NCRP 151 report. MC simulation performed reasonably in estimation in different conditions.
Conclusion: Our results showed that FF-equipped skyshine is higher than FFF LINAC and NCRP 151 is an inflexible method that does not take some effective parameters into account and calculates skyshine higher
Purpose: Diagnosis of musculoskeletal abnormalities is essential due to more than 1.7 billion people worldwide being affected by musculoskeletal disorders. In this study, we focus on diagnosing musculoskeletal abnormalities in the lower extremities within X-ray images by deep architecture neural networks.
Methods: Our dataset contains 61,098 musculoskeletal radiographic images, which includes 42658 normal images and 18440 abnormal images. Each image belongs to a single type of lower extremity radiography, including the toe, foot, ankle, leg, knee, femur, and hip joint. We proposed a new deep neural network architecture with two different scenarios that perform lower extremity lesion diagnosis functions with high accuracy. The core of the proposed method is a deep learning framework based on the Mask R-CNN and CNN. The model with the best results utilized the Mask R-CNN algorithm to generate the bounding box, followed by the CNN algorithm to detect the class based on that.
Results: The proposed model can detect different types of lower limb lesions by an AUC-ROC of 0.925, with an operating point of 0.859 sensitivity and a specificity of 0.893.
Conclusions: By comparing the different results, it can be concluded that the consecutive implementation of Mask R-CNN and CNN function better than Mask R-CNN and CNN separately.
Purpose: Therapeutic electrical stimulation of deep brain structures, such as subthalamic nucleus and the globus pallidus , is widely accepted as a treatment tool for patients with Parkinson's disease (PD). Electrical stimulation of the cerebral cortex with electrodes or transcranial stimulation can increase motor function among PD patients.
Methods: The aim of the present study was to evaluate the effects of non-invasive cortical stimulation with simulation of transcranial direct current stimulation (tDCS) technique on parts of the basal ganglia among PD patients in MATLAB software. tDCS was simulated using two different electrode placement methods (anodal stimulation of the primary motor cortex (M1) and anodal stimulation of the dorsolateral prefrontal cortex (DLPFC)) and stimulation on the target region was evaluated. All simulations were performed using head MRI images of four people with PD. The effectiveness of brain stimulation was also studied using a basal ganglia model in MATLAB software. considering the membrane potential of Globus Pallidus and Subthalamic Nucleus regions, The effectiveness of each electrode placement method was evaluated in the BG model.
Results: According to the results, direct current stimulation was propagated through electrodes placed on the scalp throughout the model. Also anodal stimulation of primary motor cortex (M1) had a better effect on globus pallidus and subthalamic nucleus than anodal stimulation of the dorsolateral prefrontal cortex (DLPFC).
Conclusion: However, the procedures for performing tDCS and invasive brain stimulation in Parkinson's disease are different, the results show that this treatment can be appropriate and improve motor function in patients with PD.
Purpose: Photon-field shaping in radiation therapy with cerrobend block or Multi-Leaf Collimator (MLC) leads to an increase in the scattered dose to the out-of-field Organ At Risk (OAR). This study aimed to measure and compare the healthy organs absorbed dose outside the cerrobend block and MLC shielded field.
Materials and Methods: Computed Tomography (CT) images were taken of a heterogeneous Thorax phantom while the target volume and organ at risk, including the spinal cord, contralateral lung, and heart were contoured. Conformal Treatment planning was performed (POP fields, total dose 40 Gy, 5 fx/week, and 2 Gy/fx) on the Prowess Panter treatment Planning System (TPS). Irradiation was performed with 6 and 18 Mv X-ray of Siemens Oncor medical linear accelerator, once for the block-shielded field and again for the MLC-shielded field. At each energy, the radiation dose to the contoured out-of-field organs was measured by an ionization chamber and compared.
Results: At both 6 and 18 MV energies, the out-of-field dose in the MLC-shielded fields was significantly lower than in the block-shielded ones (P <0.001). The out-of-filed dose for contoured organ at risk was not significantly different at 18 MV compared with 6 MV. The dose calculated by the treatment planning system showed that the healthy organs absorbed doses in all conditions were significantly lower than the dosimetry results.
Conclusion: The use of MLC to shield the lung cancer treatment filed reduces the out-of-field OARs dose compared to cerrobend block. This reduction is greater at 18 MV photon beam but this difference is not statistically significant.
Purpose: 32-time scan duration reduction of 18F-FDG Positron Emission Tomography (PET) images through the generation of standard scan duration images using a multi-slice cycle-consistent Generative Adversarial Network (cycle-GAN) was studied. Also, the effect of the image augmentation methods on the performance of the cycle-GAN model was evaluated.
Materials and Methods: Four subsets of standard and 32-time short scan duration PET image pairs, each contacting image data of 10 patients were used to train and test (80 percent for training and 20 percent for testing) a multi-slice cycle-GAN separately. Another patient’s image data was used as the validation dataset for different training subsets. When training the cycle-GAN model for each subset, two approaches were followed: with and without image augmentation. Common image quality metrics of PSNR, SSIM, and NRMSE were used to assess the generation performance of the cycle-GAN model. Paired sample t-test statistical testing with a confidence interval of 0.95 was used to determine whether the differences between approaches were statistically significant or not.
Results: For subsets 1-3, both training approaches improved the image quality of the short scan duration inputs (p<0.001) while for subset 4 only the training approach with image augmentation was capable of improving the image quality. However, the training approach with image augmentation offered better results than the approach without image augmentation (p<0.001).
Conclusion: Employing the training approach with image augmentation, the cycle-GAN model was capable of improving the image quality of 1/32nd short scan duration images through the generation of synthetic standard scan duration images. In the case of the training approach without image augmentation, except for subset 4, the model trained on all subsets 1-3 was capable of improving the image quality. Image augmentation does indeed improve the performance of the cycle-GAN model, especially in the case of insufficient available training datasets.
Purpose: Musculoskeletal systems have a complex and different nature, and it is very difficult to control issues in these systems due to various characteristics such as speed and accuracy. Therefore, investigating these musculoskeletal systems requires simple and analyzable methods. Also, due to sudden changes during the movement process, the speed and accuracy of the calculations should be proportional to the operating speed of the system. Predicting the available system norms and meeting is the next challenge of relevant studies.
Methods: Accordingly, it was attempted in the present study to investigate the knee joint function, the joint condition in an incomplete spinal cord injury (SCI), as well as its rehabilitation conditions by designing a simple mathematical model. This model is designed based on the interactions between hamstring muscles and vasti muscle group. Considering changes in the central pattern generator (CGP) as a variable input, we analyze the model output in fixed point, periodic and chaotic modes.
Results: The results of the present study show that the knee joint model output is chaotic and fixed point in the health and incomplete SCI modes, respectively. In order to rehabilitate the model, stimulation of Ia, II and Ib afferents is used in the CPG, which continues the rehabilitation process due to the change of output from the fixed-point mode to the periodic mode.
Conclusion: According to the results obtained from the knee joint mathematical model, it can be stated that this model, while having simple calculations, has acceptable accuracy and has the ability to predict different norms. It can also be hoped that, better and more accurate results will be achieved in the study of musculoskeletal systems with the development of this model.
Purpose: NADPH oxidase is one of the probable sources of Reactive Oxygen Species generated by ionizing radiation. This study aimed to determine the expressions of Nox4 and radioprotective effects of magnesium sulfate and vitamin A following whole-body 2 Gy X-ray irradiation.
Materials and Methods:.In this research, 6-7 weeks old NMRI male mice were kept in a standard cage with an appropriate temperature and 12 on 12 off light cycle. Three concentrations of vitamin A and magnesium sulfate were intraperitoneally injected into mice 2 hours before irradiation. The dose rate was 50 cGy/min at SSD = 100 cm and a field size of 10×10cm2. The mice were anesthetized and sacrificed by cervical dislocation 24 hours after irradiation. Then, the expression of Nox4 was assessed by Real-Time PCR.
Results:.There were significant differences between the mean of gene expression in groups treated with vitamin A and magnesium sulfate compared to only radiation group (P<0.05).
Conclusion:.Based on the results of this study, it is likely that vitamin A and magnesium sulfate neutralize the harmful effects of free radicals due to their antioxidant properties.
Studies have been conducted on both normal and abnormal samples have shown transcranial brain stimulation to be effective in improving cognitive functioning. Training in cognitive skills has also appeared to be effective. To enhance or rehabilitate core cognitive processes, neuropsychologists and clinicians usually use either one of these or a combination of both. In this study, we reviewed the literature to investigate the effects of brain stimulation alone or combined with cognitive training on attention and working memory. It was concluded that the combined method can be more effective than brain stimulation alone. However, there is no sufficient evidence to make a conclusive statement.
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