فهرست مطالب

Medical Signals and Sensors - Volume:8 Issue: 2, 2018
  • Volume:8 Issue: 2, 2018
  • تاریخ انتشار: 1397/03/19
  • تعداد عناوین: 8
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  • Omid Bazgir *, Seyed Amir Hassan Habibi, Lorenzo Palma, Paola Pierleoni, Saba Nafees Pages 65-72
    Tremor is one of the most common symptoms of Parkinson’s disease (PD), which is widely being used in the diagnosis procedure. Accurate estimation of PD tremor based on Unifed PD Rating Scale (UPDRS) provides aid for physicians in prescription and home monitoring. This article presents a robust design of a classification system to estimate PD patient’s hand tremors and the results of the proposed system as compared to the UPDRS. A smartphone accelerometer sensor is used for accurate and noninvasive data acquisition. We applied short‑time Fourier transform to time series data of 52 PD patients. Features were extracted based on the severity of PD patients’ hand tremor. The wrapper method was employed to determine the most discriminative subset of the extracted features. Four different classifiers were implemented for achieving best possible accuracy in the estimation of PD hand tremor based on UPDRS. Of the four tested classifers, the Naive Bayesian approach proved to be the most accurate one. The classification result for the assessment of PD tremor achieved close to 100% accuracy by selecting an optimum combination of extracted features of the acceleration signal acquired. For home health‑care monitoring, the proposed algorithm was also implemented on a cost‑effective embedded system equipped with a microcontroller, and the implemented classification algorithm achieved 93.8% average accuracy. The accuracy result of both implemented systems on MATLAB and microcontroller is acceptable in comparison with the previous works.
    Keywords: Classification, home monitoring, Parkinson's tremor, smartphone, supervised learning, Unified Parkinson's Disease Rating Scale
  • Said Boujraf * Pages 73-80
    A color mapping of fber tract orientation using diffusion tensor imaging (DTI) can be prominent in clinical practice. The goal of this paper is to perform a comparative study of visualized diffusion anisotropy in the human brain anatomical entities using three different color‑mapping techniques based on diffusion‑weighted imaging (DWI) and DTI. The frst technique is based on calculating a color map from DWIs measured in three perpendicular directions. The second technique is based on eigenvalues derived from the diffusion tensor. The last technique is based on three eigenvectors corresponding to sorted eigenvalues derived from the diffusion tensor. All magnetic resonance imaging measurements were achieved using a 1.5 Tesla Siemens Vision whole body imaging system. A single‑shot DW echoplanar imaging sequence used a Stejskal–Tanner approach. Trapezoidal diffusion gradients are used. The slice orientation was transverse. The basic measurement yielded a set of 13 images. Each series consists of a single image without diffusion weighting, besides two DWIs for each of the next six noncollinear magnetic feld gradient directions. The three types of color maps were calculated consequently using the DWI obtained and the DTI. Indeed, we established an excellent similarity between the image data in the color maps and the fber directions of known anatomical structures (e.g., corpus callosum and gray matter). In the meantime, rotationally invariant quantities such as the eigenvectors of the diffusion tensor reflected better, the real orientation found in the studied tissue.
    Keywords: Color mapping, diffusion tensor, human brain anatomy, magnetic resonance imaging
  • Hossam Donya * Pages 81-86
    The accurate calculation of doses during external radiotherapy sessions is necessary. Recently, the models used for this purpose have been the point kernel, pencil‑beam, and collapsed cone superposition/convolution combination models. In this study, it is aimed to determine point/pencil‑beam kernels to be used in dose calculations. For this purpose, tallying pencil‑beam fluence based on Monte Carlo (MC) simulations is investigated by scoring a volume of interest centered in a cubic water phantom at a depth of 10 cm and the irradiated feld of 10 cm × 10 cm. The fluence is calculated for each mono‑energetic photon ranging from 0.25–6 MV at increments of 250 keV. The output of the four fluence kernels along the depth Z around the central axis is categorized for both the primary and secondary photons and electrons. Here, a database for pencil‑beam kernels is established for each category. For validation purposes, other MC simulations are carried out for fluence calculations as produced by the predetermined poly‑energetic spectra for a Varian 6 MV linear accelerator. The net results show a good ft of the two convoluted fluence spectra quantities for both mono‑energetic and poly‑energetics‑based simulations except little singular peaks.
    Keywords: Electron fluence, Monte Carlo simulation, pencil?beam kernel, photon fluence, solid?state dosimeters
  • Seyedeh Yasamin Boutorabi, Ali Sheikhani * Pages 87-94
    Today, the neuroscience has growth in many aspects, and the effects of different factors on memory obtained many achievements. Several scientifc and experimental studies evaluated effects of music on style and behavior of people; in this study, we evaluated memory between two groups of people, the professional pianists and normal people, through processing their electroencephalogram (EEG) signals using the coherence measure. In this study, EEG signals from 17 subjects during two memory tasks were recorded. After that, these signals were preprocessed, and spectral coherence connectivity measure between pair of electrodes was computed and then compared in the fve frequency bands using independent t‑test. Results of this statistical analysis for working memory task showed signifcant differences in the temporal, central, and parietal lobes, especially in P7, P3, Pz, T8, C3, and C4 electrodes. As we know, these differences are related to learned skills and activities, words and sounds perception, and memory. Furthermore, for iconic memory task, signifcant differences were observed in the right hemisphere of these two groups. From this task, we can say professional pianists are different from normal people in the perception of images and creativity. Results of this study show the effects of music on human brain and memory.
    Keywords: Electroencephalogram, iconic memory, spectral coherence, working memory
  • Mohsen Saeb, Daryoush Shahbazi? *, Gahrouei, Shahram Monadi Pages 95-100
    This study aimed to evaluate the overall accuracy of the beam commissioning criteria of targeted image‑guided radiation therapy (TiGRT) treatment planning system (TPS) based on the American Association of Physicists in Medicine (AAPM) Task Group Report 119 (TG‑119). The work was performed using 6 MV energy LINAC with a variable dose rate of 200 MU/min which equipped with the high‑quality external TiGRT dynamic multileaf collimator model H. The AAPM TG‑119 intensity‑modulated radiation therapy (IMRT) commissioning tests are composed of two preliminary tests and four clinical test cases. The clinical tests consisted of mock prostate, mock head and neck, C‑shaped target, and multitarget. EDR2 flm was used for evaluating the IMRT plans and point dose measured by a Pinpoint chamber positioned in slab phantom. The flm analysis was done with the Sun Nuclear Corporation patient software. The dose prescription for each fraction was 200 cGy in mock prostate, mock head and neck, C‑shaped target, and multitarget. Dose distributions were analyzed using gamma criteria of 3% and 2% dose difference (DD) and 3 and 2 mm distance to agreement. In all test cases, the gamma criteria for 2%/2 and 3%/3 were found to be 94% and 98%, respectively. Results showed that the average gamma criteria result was in the range of 99.1% to 93% (3%/3, 2%/2) overall test cases. Findings were favorable and in some tests were comparable with the other studies. The dose point values were within the mean values of the range reported by TG‑119. Overall, the TiGRT TPS is needed to apply IMRT technique in radiation therapy centers.
    Keywords: American Association of Physicists in Medicine Task Group Report 119, intensity modulated radiation therapy, radiation therapy, targeted image?guided radiation therapy, treatment planning system
  • Ensiyeh Taheri, Mohammad Mehdi Amin, Hamidreza Pourzamani, Ali Fatehizadeh, Mohammad Ghasemian, Bijan Bina * Pages 101-107
    Hydrogen gas is the cleanest energy carrier and could be produced by biological process. Dark fermentation is one of the biohydrogen production methods that carried out just on organic wastes conversion. In this study, the batch tests were conducted to compare the biohydrogen production and glucose fermentation via acetate‑butyrate and acetate‑ethanol metabolic pathway induced by NaOH and KOH (10 M) pretreatment. In batch test, the glucose concentration in the feed was varied from 3.75 to 15 g/L under mesophilic conditions (37°C ± 1°C). In order to sludge pretreatment, NaOH and KOH (as an alkaline agent) was used. Batch tests showed that maximum biohydrogen production under NaOH (2.7 ± 0.5 L) and KOH (2.2 ± 0.7 L) pretreatment was achieved at 15 g/L of influent glucose. In the batch test, with increasing influent glucose concentration, the lower yields of hydrogen were observed. The biohydrogen reactions had good electron closure (5.2 –13.5%) for various glucose concentrations and pretreatments. For NaOH and KOH pretreatment, the biohydrogen yield decreased from 2.49 to 1.63 and from 2.22 to 1.2 mol H2/mol glucose, respectively, when glucose concentration increased from 3.75 to 15 g/L. By applying alkaline sludge pretreatment by NaOH and KOH, the glucose fermentation was followed with acetate‑butyrate and acetate‑ethanol metabolic pathway, respectively. The lower biohydrogen yields were observed under acetate‑ethanol metabolic pathway and related to metabolically unfavorable for biohydrogen production.
    Keywords: Acetate?butyrate pathway, acetate?ethanol metabolic, biohydrogen production
  • Mohammad Rafenia*, Ashkan Bigham, Seyed Ali Hassanzadehtabrizi Pages 108-118
    At present, solvothermal fabrication method has widely been applied in the synthesis of spinel ferrite nanoparticles (SFNs), which is mainly because of its great advantages such as precise control over size, shape distribution, and high crystallinity that do not require postannealing treatment. Among various SFNs, Fe3O4 nanoparticles have attracted tremendous attention because of their favorable physical and structural properties which are advantageous, especially in biomedical applications, among which the vast application of these materials as targeted drug delivery systems, hyperthermia, and imaging agents in cancer therapy can be mentioned. The main focus of this study is to present an introduction to solvothermal method and key synthesis parameters of SFNs through this synthesis route. Moreover, most recent progress on the potential applications of Fe3O4 nanoparticles as the most important compound among the spinel ferrites family members is discussed
    Keywords: Application, magnetite, solvothermal synthesis route, spinel ferrites
  • Somayeh Kakehbaraei, Hadi Seyedarabi *, Ali Taghavi Zenouz Pages 119-124
    Teeth segmentation is an important task in computer‑aided procedures and clinical diagnosis. In this paper, we propose an accurate and robust algorithm based on watershed and morphology operators for teeth and pulp segmentation and a new approach for enamel segmentation in cone‑beam computed tomography (CBCT) images. Proposed method consists of fve steps: acquiring appropriate CBCT image, image enhancement, teeth segmentation using the marker‑controlled watershed (MCW), enamel segmentation by global threshold, and fnally, utilizing the MCW for pulp segmentation. Proposed algorithms evaluated on a dataset consisting 69 patient images. Experimental results show a high accuracy and specifcity for teeth, enamel, and pulp segmentation. MCW algorithm and local threshold are accurate and robust approaches to segment tooth, enamel, and pulp tissues. Methods overcome the over‑segmentation phenomenon and artifacts reduction.
    Keywords: Dental cone?beam computed tomography, marker?controlled watershed, morphology operators, segmentation