Measurement and Calculation of SAR Due to 900 MHz Electromagnetic Waves

Purpose: The widespread use of mobile phones and Base Transceiver Stations (BTSs) has generated public concern about exposure to Electromagnetic (EM) waves. In this study, the electric field intensity and Specific Absorption Rate (SAR) in the emergency, general hospitalization, radiology, and laboratory departments of four hospitals in Arak (Iran) are reported. Materials and Methods: Electric field strength in the 900 MHz frequency band was obtained using a TES 592 radiometer. Then, SAR induced in the brain, skin, fat and bone tissues were calculated based on equations and the obtained values were compared with the thresholds recommended by the International Commissions. Results: The obtained results showed that the electric field’s mean value was 1.334 V/m which is almost 2.7% of the threshold introduced by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and 2.6% of the threshold adopted by the Institute of Electrical and Electronics Engineers (IEEE). The highest SAR value was 1.6 W/kg for the skin, which is lower than the threshold values presented by ICNIRP (2 W/kg) and IEEE (1.6 W/kg). Conclusion: The findings of the present work show that for both quantities in Arak hospitals the SAR values are less than the thresholds announced by IEEE and ICNIRP committees. To deal with the concerns of the community that is generally caused by a lack of awareness, the executions of educational and public awareness programs are recommended.

Estimating the Entrance Surface Dose in the Eyes, Thyroid, and Parotid Gland Regions in Adult and Pediatric Groups: A Cone-Beam Computed Tomography Technique

Purpose: This study aimed to determine the Entrance Surface Dose (ESD) of sensitive organs in Cone-Beam Computed Tomography (CBCT) imaging of the maxillofacial region in the two age groups of adult and pediatric. Materials and Methods: In this work, the measurements were performed using Thermo Luminescent Dosimeters (TLD-GR200). The imaging was performed using a PROMAX 3D CBCT scanner for 30 adults and 20 pediatric patients. The ESD value for each patient in the region of eyes, thyroid, and parotid glands was measured by 15 TLDs during CBCT of maxillofacial. Results: The highest and lowest mean values of ESDs were related to the parotid and thyroid gland regions in adults, 4.77 ± 0.61 mGy and 0.37 ± 0.16 mGy, respectively. In addition, these values were obtained 2.97 ± 0.36 mGy and 0.35 ± 0.12 mGy in pediatric groups as the highest and lowest values in that order. The results showed that the ESD values of the parotid gland regions in maxilla and mandible examinations had a significant difference (P <0.05). In addition, there was a significant difference between the ESD values of the parotid gland regions among the adults and pediatric groups (P <0.05). Conclusion: According to the results, the ESD values in both age groups were higher in the parotid gland region during maxillofacial CBCT examinations. Therefore, it is recommended to set radiation parameters like mAs as low as possible for reducing the patient dose, especially pediatric patients due to the more sensitive organs.

Gamma-Ray Attenuation Characteristics of Some Essential Amino Acids for 57Co, 192Ir, 18F, and 116mIn Sources

Purpose: In different tissues of the body, proteins are important parts that are made up of building blocks called amino acids. Considering the wide applications of radioactive sources in industry and medicine, the need to study the attenuation characteristics of amino acids is determined. Materials and Methods: To study the attenuation characteristics of five types of amino acids, MCNPX Monte Carlo code and XMuDat program were used. Linear and mass attenuation coefficients, half and tenth value layers, mean free path, effective atomic and electronic cross-sections, effective atomic numbers and effective electron densities were calculated. 57Co, 192Ir, 18F, and 116mIn gamma sources were considered for this study. To validate the theoretical results, the obtained values were compared with the available experimental data. Results: The difference between the theoretical and experimental results was less than 11%. The results showed that with increasing photon energy, the linear and mass attenuation coefficients and effective atomic and electronic cross-sections decreased, while the half and tenth value layers and mean free path quantities increased. Furthermore, the linear attenuation coefficients, the effective atomic and electronic cross-sections, as well as the effective atomic number values increased with increasing amino acid density, while the effective electron density behaves independently of the amino acid density. Conclusion: The presented theoretical methods produced data similar to experimental results with fair accuracy, so by using these methods, attenuation properties of other amino acids can be obtained over a wide range of energies.

Prediction of Self-Control Based on Cognitive Intelligence and Socio-Emotional Behavior Assessments in Early Childhood

Purpose: The infrastructure core of self-control, as an indicator of future success, is unsettled. To better investigate the nature of self-control, and strengthening it, it is necessary to know to what extent is self-control based on cognitive or socio-emotional abilities? Materials and Methods: The authors measured the cognitive intelligence and socio-emotional behavior of 377 healthy Iranian children (girl=46.1%) by Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) and Kindergarten Inventory of Social-Emotional Tendencies (KIST) at the age range of 42-66 months (mean=54.86, SD=5.88). Then, they assessed their Self-control competency 18 months later, to know which component of WPPSI or KIST could better predict Self-control. Results:.The correlation matrix between all study variables shows that there are more positive significant correlations among Self-control with KIST subsets (5/6) than WPPSI subsets (2/10). The results of automatic linear modelling show that the significant predictors of self-control in the total model (R2=0.161) were Hyperactivity-Maladaptive Behavior (HMB(, (coefficient=.137, importance=0.781), and Daily Living Skills (DLS) (coefficient=.127, importance=0.125), so HMB is the best predictor of self-control among the subsets examined in our research. Therefore, self-control is more related to the socio-emotional than cognitive domain. Conclusion: We suggest children who get a low score in socio-emotional assessments, need early supportive intervention and rehabilitation to prevent the maldevelopment of self-control.

Photodynamic Therapy as A New Technology for Inactivation of Coronavirus Disease (COVID-19)

Purpose: Coronavirus Disease (COVID-19) could be an emerging disease with a severe acute respiratory infection, and its epidemiology and unique medicinal properties are perpetually increasing. Regarding the lack of COVID-19 controls, this needs current technical events to worsen and treat. Antiviral Photodynamic Therapy (aPDT) could also be effective in reducing and inhibiting the coronavirus. aPDT with various photosensitizers is a very favorable procedure to manage viral infections. Materials and Methods: A total of 37 articles related to the publication of this review manuscript were mentioned. Several scientific databases such as Scopus, PubMed, Web of Science (ISI), and Google Scholar have checked the key phrases of COVID-19, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), photodynamic therapy, and antiviral photodynamic therapy. All 50 main studies were found, and 37 related studies were deemed suitable for this study after review. Results: Studies have shown that aPDT with different photosensitizers can be used to treat viral lung complications caused by infectious pathogens such as Middle East Respiratory Syndrome (MERS), SARS-CoV-2, and influenza. Recent studies have shown that aPDT-mediated Methylene Blue (MB) can help control and eradicate coronavirus. In general, more research is needed to use antiviral photodynamic therapy to control COVID-19. Conclusion: Regarding the lack of treatment for COVID-19, MB-mediated aPDT can help reduce the impact of COVID-19. More evidence is needed to support aPDT as a treatment (SARS-CoV-2).

The Classification of Heartbeats from Two-Channel ECG Signals Using Layered Hidden Markov Model

Purpose: Cardiac arrhythmia is one of the most common heart diseases that can have serious consequences. Thus, heartbeat arrhythmias classification is very important to help diagnose and treat. To develop the automatic classification of heartbeats, recent advances in signal processing can be employed. The Hidden Markov Model (HMM) is a powerful statistical tool with the ability to learn different dynamics of the real time-series such as cardiac signals. Materials and Methods: In this study, a hierarchy of HMMs named Layered HMM (LHMM) was presented to classify heartbeats from the two-channel electrocardiograms. For training in the first layer, the morphology of the heartbeats was used as observations, while observations in the second layer were the inference results of the first layer. The performance of the proposed LHMM was evaluated in classifying three types of heartbeat arrhythmias (Atrial premature beats (A), Escape beats (E), Left bundle branch block beats (L)) using fifteen records of the MIT-BIH arrhythmia database. Furthermore, the obtained results of the proposed model were compared with other HMM generalizations. Results: The best average accuracy was achieved 97.10±1.63%. The best sensitivity of 96.8±1.24%, 98.85±0.52%, and 95.64±1.41 were obtained for A, E, and L, respectively. Furthermore, the results of the proposed method were better than other HMM generalizations. Conclusion: Extracting information from time-series dynamics by HMM-based methods has good classification results. The proposed model shows that applying a two-layered HMM can lead to better extraction of information from the observations; therefore, the classification performance of cardiac arrhythmias has been improved using LHMM.

Human Muscle Synergy Analysis to Approach the Understanding of Brain Control Algorithm

Purpose: Muscle synergy is a functional unit that coordinates the activity of a number of muscles. In this study, the extraction of muscle synergies in three types of hand movements in the horizontal plane is investigated. Materials and Methods: So, after constructing the tracking pattern of three signals, by LabVIEW, the Electromyography (EMG) signal from six muscles of hand was recorded. Then time-constant muscle synergies and their activity curves from the recorded EMG signals were extracted using Non-negative Matrix Factorization (NMF) method. Results: Comparison of these patterns showed that the non-random motions’ synergies were more similar than the random motions among different individuals. It was observed that in all movements, the similarity of the synergies in one cluster was greater than the similarity of their corresponding activation curves. Conclusion: The results showed that the complexity of the recurrence plot in random movement is greater than that of the other movements.

Estimating Radiotherapy-Induced Secondary Cancer Risk Arising from Brain Irradiation at High Energy: A Monte Carlo Study

Background: The present study aims to determine the whole-body out-of-field photon dose equivalents of high-energy conventional radiation therapy treatment. Also, it is tried to estimate the probability of fatal secondary cancer risk for the susceptible organs using a Monte Carlo (MC) code. Materials and methods: An Monte Carlo N-Particle eXtended (MCNPX)-based model of 18-MV Medical Linear Accelerator (LINAC) was created to calculate the out-of-field photon dose equivalent at the locations of fascinating organs in the mathematical female Medical Internal Radiation Dosimetry (MIRD) phantom. Then, the secondary malignancies risk was estimated based on out-of-field doses and radiation risk coefficients according to the National Council of Radiation Protection and Measurements (NCRP). Results: The average photon equivalent dose in out-of-field organs was about 3.25 mSv/Gy, ranging from 0.23 to 37.2 mSv/Gy, respectively, for the organs far from the Planning Target Volume (PTV) (Eyes) and those close to the treatment field (rectum). The entire secondary cancer risk for the 60 Gy prescribed dose to isocenter was obtained as 2.9987%. Here, the maximum doses among off-field organs were related to stomach (0.0805%), lung (0.0601%), and thyroid (0.0404%). Conclusion: Regarding the estimated values for the probability of secondary cancer risk, it is suggested to perform a long-term follow-up of brain cancer patients regarding the prevalence of thyroid, stomach, and lung cancer after completing the treatment course.

Robotic Surgery Advantages and Challenges

The interest in using robotic surgery especially for gynecology, gastroenterology, and urology is increasing every day as this technology is expected to be the first line of surgery in many medical fields in the near future. This attentiveness is due to the unique features of this method and its advantages over open surgery and laparoscopy technique. Knowing curiously about robotic surgery, its components, characteristics, advantages, and challenges is crucial to be prepared for such huge evolution and to be engaged in the advancement of this new technology.

The Relationship between Cellphone Usage and Sleep Quality among Hospital Staff

Purpose: Despite the two decades of using cell phones, there are still considerable controversies about the biological effects of the Electromagnetic Fields (EMFs) produced by cell phones. Sleep disorder among hospital staff is an important issue for the health care system not only due to the health of its employees but also to the reduction of the staff performance quality and the increase in medical errors. This study aimed to explore factors that may affect the sleep quality of hospital staff and to examine the association between sleep quality and cell phone usage. Materials and Methods: In this study, participants consisted of 288 employees (35.51 ± 8.42 years old) of two hospitals, and their sleep quality was assessed using the Pittsburgh sleep quality index. Results: Sixty-six percent of participants had good sleep quality and nearly 68% of the employees worked in shifts. The cell phone use among participants averaged 10.74 ± 3.03 years, and less than half of the staff stated that call durations of their cell phones were less than 5 h/day. More than 90% of the staff mentioned no use of hands-free. There were no statistically significant differences between job characteristics, sleep quality, and items related to cell phones, except the use of hands-free. Conclusion: In our study, using hands-free during phone calls was associated with poor quality sleep. Different factors, such as decreased levels of electromagnetic fields reaching the brain, can be involved in this effect. These results must be interpreted with caution due to the low number of subjects and the limitations of our study.