Journal of Biomedical Physics & Engineering
Volume:11 Issue: 6, Nov-Dec 2021

During deep space missions, astronauts are exposed to highly ionizing radiation, incl. neutrons, protons and heavy ions from galactic cosmic rays (GCR), solar wind (SW) and solar energetic particles (SEP). This increase the risks for cancerogenisis, damages in central nervous system (CNS), cardiovascular diseases, etc. Large SEP events can even cause acute radiation syndrome (ARS). Long term manned deep space missions will therefor require unique radiation protection strategies. Since it has been shown that physical shielding alone is not sufficient, this paper propose pre-flight screening of the aspirants for evaluation of their level of adaptive responses. Methods for boosting their immune system, should also be further investigated, and the possibility of using radiation effect modulators are discussed. In this paper, especially, the use of vitamin C as a promising non-toxic, cost-effective, easily available radiation mitigator (which can be used hours after irradiation), is described. Although it has previously been shown that vitamin C can decrease radiation-induced chromosomal damage in rodents, it must be further investigated before any conclusions about its radiation mitigating properties in humans can be concluded.

Dynamic protein-protein interaction networks (DPPIN) can confirm the conditional and temporal features of proteins and protein complexes. In addition, the relation of protein complexes in dynamic networks can provide useful information in understanding the dynamic functionality of PPI networks. In this paper, an algorithm is presented to discover the temporal association rule from the dynamic PPIN dataset. In this analytical study, the static protein-protein interaction network is transformed into a dynamic network using the gene expression thresholding to extract the protein complex relations. The number of presented proteins of the dynamic network is large at each time point. This number will increase for extraction of multidimensional rules at different times. By mapping the gold standard protein complexes as reference protein complexes, the number of items decreases from active proteins to protein complexes at each transaction. Extracted sub graphs as protein complexes, at each time point, are weighted according to the reference protein complexes similarity degrees. Mega-transactions and extended items are created based on occurrence bitmap matrix of the reference complexes. Rules will be extracted based on Mega-transactions of protein complexes. The proposed method has been evaluated using gold standard protein complex rules. The amount of extracted rules from Biogrid datasets and protein complexes are 281, with support 0.2. The characteristic of the proposed algorithm is the simultaneous extraction of intra-transaction and inter-transaction rules. The results evaluation using EBI data shows the efficiency of the proposed algorithm.

Fractional flow reserve (FFR) is a gold standard to assess the impact of stenosis on the blood flow. The FFR method enhances diagnostic accuracy, lessens the need for stenting, and reduces costs. However, FFR is used in less than 10% of percutaneous coronary intervention (PCI) procedures because it needs pressure wires to measure the distal and proximal pressures and adenosine to create hyperemic conditions. Pressure-wire-based FFR measurement is, therefore, expensive and invasive. This study aims to introduce a new approach on the basis of 3D coronary angiography and the Thrombolysis in Myocardial Infarction (TIMI) frame count for fast computation of FFR in patients with coronary artery disease. In this simulation study, we herein introduce Non-Invasive Flow Ratio drawing upon CFD to measure FFR based on coronary angiography images with less run time. In this study, 3D geometry was created based on coronary angiography images. The mean volumetric flow rate was calculated using the TIMI frame count. FFR calculated based on CFD was compared with pressure-wire-based FFR and NiFR was calculated in 85 patients. The NiFR (r = 0.738, P< 0.001) exhibited a strong correlation with pressure-wire-based FFR. The result indicated that FFR was higher than 0.8 in the arteries with non-signif icant stenosis and lower than 0.8 in the arter ies with significant stenosis. The computational simulation of FFR and hemodynamic parameters such as pressure drop is a safe, efficient, and cost-effective method to evaluate the severity of coronary stenosis.

Exposure to high-dose ionizing radiation is known as a human carcinogen factor, but our information about the effects of low-dose ionizing radiation such as occupational exposures is limited. The main concern of scientific community is biological consequences due to low-dose radiations. This study aims to evaluate the effects of low-dose γ-radiation on expression changes of apoptotic genes (bax and bcl-2) in the rat peripheral blood lymphocytes. In this experimental study, 42 adult male rats were classified into 6 groups, which was exposed to various doses values ranged from 20 mGy to 1000 mGy by γ-rays from a Co-60 source. Blood samples were provided for analysis of gene expression 24 h after gamma radiation by relative quantitative Reverse Transcription - Polymerase Chain Reaction (RT-PCR). Radiation sensitivity of rat lymphocytes was measured by the bax/bcl-2 ratio as a predictive marker for radio-sensitivity. The results of this study showed that low dose of gamma radiation can induce down-regulation of bax in rat peripheral blood lymphocytes. Despite other mechanisms of cellular radio-protection, changes in expression of these apoptotic genes can be the primary pathway in responses of the lymphocytes radio-protection to the exposure. Our study revealed a significant decrease in the bax/bcl-2 ratio at 50 mGy dose compare to control and the other irradiated groups (p < 0.05). These results suggest that changes in the bax/bcl-2 ratio especially in radiation workers, as a key factor in apoptosis, can be considered as a biological marker in low-dose gamma radiation.

Today, the most common method for kidney stone therapy is extracorporeal shock wave lithotripsy. Current research is a numerical simulation of kidney stone fragmentation via ultrasonic shock waves. Most numerical studies in lithotripsy have been carried out using the elasticity or energy method and neglected the dissipation phenomenon. In the current study, it is solved by not only the linear acoustics equation, but also the Westervelt acoustics equation which nonlinearity and dissipation are involved. This study is to compare two methods for simulation of shock wave lithotripsy, clarifying the effect of shock wave profiles and stones’ material, and investigating side effects on surrounding tissues. Computational study is done using COMSOL Multiphysics, commercial software based on the finite element method. Nonlinear governing equations of acoustics, elasticity and bioheat-transfer are coupled and solved. A decrease in the rise time of shock wave leads to increase the produced acoustic pressure and enlarge focus region. The shock wave damages kidney tissues in both linear and nonlinear simulation but the damage due to high temperature is very negligible compared to the High Intensity Focused Ultrasound (HIFU). Disaffiliation of wave nonlinearity causes a high incompatibility with reality. Stone’s material is an important factor, affecting the fragmentation.

Balance ability is a crucial component of independent daily activities among the older adultss. Balance impairment is one of the major risk factors for falls and related complications. The present study aims to investigate and compare the effect of neurofeedback training and balance training on balance and fall risk among older adults. In this randomized controlled trial, a total of 48 older adults aged more than 65 years were recruited and randomly assigned into two groups, neurofeedback group (n=24) and balance exercise group (n=24). Prior to the intervention, the static balance, dynamic balance, and fall risk were measured using Biodex D balance system and Fullerton Advanced Balance scale. Subjects in neurofeedback group received neurofeedback training for 12 sessions of 30-min, every other day. Moreover, subjects in balance exercise group received balance training for four weeks in 12 sessions (45-minute) every other day. After the intervention, balance measurements were repeated in both groups. The significance level was set at p Static balance and dynamic balance were shown to significantly improve, after the interventions (p <0.001). Furthermore, fall risk was significantly reduced, after the trial (p <0.001). In addition, the therapeutic effect of neurofeedback training was not less significant than exercises on balance in the older adults (p <0.001). The findings suggest that both neurofeedback training and balance training improved balance ability among the older adults. Results also show the therapeutic effect of neurofeedback training on balance in older people. However, further research is required to accurately investigate the long-term effects of these two treatment methods among the older adults.

In developing countries like India, cobalt-60 machines still find their applicability, considering the cost and maintenance issues. With a view to deliver conformal treatment plans using teletherapy machines, an automated Multi-Leaf Collimator (MLC) was developed for the existing machines as a retrofit attachment to the collimator assembly without any modifications to the unit. This study aims to investigate the radiation characteristics of leaf designs incorporated in two add-on prototype MLC systems with respect to the shape of leaf projected at the isocenter plane and the isodose distribution around the target. Besides, the dosimetric characteristics of prototype MLC with divergent leaf design are validated through simulation and experimental measurements. In this experimental study, two add-on prototype MLC systems were designed and fabricated. The characteristic measurements of leaf designs incorporated in both the prototypes were carried out using Gafchromic films (GAF) and compared with Monte Carlo (MC) simulations. For divergent leaf design, beam profiles were obtained using Monte Carlo simulations which are complemented with the results obtained from measurements of radiochromic films and ionization chamber (IC) profiler. Dosimetric characteristics like radiation field width and beam penumbra were evaluated. The Monte Carlo simulated data are in agreement with experimental data from IC profiler as well as from Radiochromic films. The results of this study are well within acceptable tolerance limits. The prototype MLC system designed for existing telecobalt machines supports its clinical applicability for conformal therapy to better manage treatment in rural areas, which can provide superior cost effective treatments.

The use of boluses for radiation therapy is very necessary to overcome the problem of sending inhomogeneous doses in the target volume due to irregularities on the surface of the skin. The bolus materials for radiation therapy need to be evaluated. The present study aims to evaluate some handmade boluses for megavoltage electron and photon radiation therapy. Several dosimetric properties of the synthesized boluses, including relative electron density (RED), transmission factor, mass attenuation coefficient, percentage depth dose (PDD), and percentage surface dose (PSD) were investigated. In this experimental study, we evaluated natural rubber, silicone rubber mixed either with aluminum or bismuth, paraffin wax, red plasticine, and play-doh as soft tissue equivalent. CT-simulator, in combination with ECLIPSE software, was used to determine bolus density. Meanwhile, Linear Accelerator (Linac) Clinac iX (Varian Medical Systems, Palo Alto), solid water phantom, and Farmer ionization chamber were used to measure and analyze of dosimetric properties. The RED result analysis has proven that all synthesized boluses are equivalent to the density of soft tissue such as fat, breast, lung, and liver. The dosimetric evaluation also shows that all synthesized boluses have a density similar to the density of water and can increase the surface dose with a value ranging from 6-20% for electron energy and 30-50% for photon energy. In general, all synthesized boluses have an excellent opportunity to be used as an alternative tissue substitute in the surface area of the body when using megavoltage electron and photon energy.

Some parametric models are used to diagnose problems of lung segmentation more easily and effectively. The present study aims to detect lung diseases (nodules and tuberculosis) better using an active shape model (ASM) from chest radiographs. In this analytical study, six grouping methods, including three primary methods such as physicians, Dice similarity, and correlation coefficients) and also three secondary methods using SVM (Support Vector Machine) were used to classify the chest radiographs regarding diaphragm congestion and heart reshaping. The most effective method, based on the evaluation of the results by a radiologist, was found and used as input data for segmenting the images by active shape model (ASM). Several segmentation parameters were evaluated to calculate the accuracy of segmentation. This work was conducted on JSRT (Japanese Society of Radiological Technology) database images and tuberculosis database images were used for validation. The results indicated that the ASM can detect 94.12 ± 2.34 % and 94.38 ± 3.74 % (mean± standard deviation) of pulmonary nodules in left and right lungs, respectively, from the JRST radiology datasets. Furthermore, the ASM model detected 88.33 ± 6.72 % and 90.37 ± 5.48 % of tuberculosis in left and right lungs, respectively. The ASM segmentation method combined with pre-segmentation grouping can be used as a preliminary step to identify areas with tuberculosis or pulmonary nodules. In addition, this presented approach can be used to measure the size and dimensions of the heart in future studies.

Tracheostomy is one of the most important airway management procedures in patients with respiratory problems. This procedure might be the only option for patients with airway and respiratory problems, who are not able to have an appropriate ventilation and oxygenation. For this purpose, tracheostomy tubes are used with different applications. One of these types of tubes is the cuffed tracheostomy tube, used for fixation, positive pressure ventilation and aspiration prevention. Nevertheless, there are two common problems with using these regular tracheostomy tubes. First, these tracheostomy tubes do not have a unique cuff pressure monitoring system. Although there are portable monitoring devices for such purpose in intensive care units (ICU), they are shared among several patients, increasing the risk of infection transmission. Second, due to the presence of the patient’s thick secretions, the tracheostomy tube becomes obstructed and inefficient. The pathway does not get open even through suction and thus the tracheostomy tube must be replaced. In order to resolve these problems, the inner lumen tracheostomy tube capable of continuous monitoring of cuff pressure has been invented with two techniques, which set it apart from other related tools. The invented optimized tracheostomy tube has been developed with different techniques through creating a disposable monometer system attached to it as well as a removable inner lumen embedded in it.

Nowadays, as technology grows, human life formation changes every second. These changes sometimes create harmful habits and affect our lifestyle, which unfortunately bring various diseases and disorders. ADHD (Attention Deficit Hyperactivity Disorder) & SPD (Sensory Processing Disorder) are common disorders in children. By giving children the right treatment at the younger ages, we can help them overcome their disabilities and not face any symptoms in their adulthood. The multi-sensory balance board is designed and developed to help medics diagnose the disorders in patients at early stages and monitor the treatment progress. The balance board uses multiple sensors to detect common human senses, visual, auditory, balance, and tactile sensing. Due to the safety issues for children during the COVID-19 pandemic, the balance board has been clinically tested for adults with stroke disorder. The research has concluded that it provides a fast low-cost with reliable results to diagnose the disorders in patients.