Journal of Biomedical Physics & Engineering
Volume:8 Issue: 2, Mar-Apr 2018

In 2016, scientists reported that human exposure to low doses of ionizing radiation (CT scans of the brain) might relieve symptoms of both Alzheimer’s disease (AD) and Parkinson disease (PD). The findings were unbelievable for those who were not familiar with neurohormesis. X-ray stimulation of the patient’s adaptive protection systems against neurodegenerative diseases was the mechanism proposed by those authors. Now, some more recent studies performed in the field of neurobiological research confirm that low levels of stress can produce protective responses against the pathogenic processes. This paper outlines possible protective consequences of LDR in preventing the pathogenesis of AD through mechanisms such as restoring the myelin sheath and preventing neurodegeneration caused by oxidative stress. Focal demyelination is frequently reported in the proximity of beta-amyloid plaques within neocortex. Extracellular accumulation of amyloid is among well-characterized pathological changes in AD. It should be noted that LDR has been shown to contribute to the regeneration and functional recovery after transverse peripheral nerve injury (through inducing increased production of VEGF and GAP-43), which advances both the axonal regeneration and myelination. Another mechanism which is possibly involved is preventing neurodegeneration caused by oxidative stress. While high doses can induce reactive oxygen species (ROS) formation, oxidative stress and neuro-inflammation, substantial evidence now indicates that LDR can mitigate tissue damage through antioxidant defenses. Although adult neurogenesis has been reported to be beneficial for the regeneration of nervous system, some studies demonstrate that neurogenesis increases in AD brains. In spite of these reports, cellular therapy is introduced as a promising strategy for AD, and hence, LDR can affect the proliferation and differentiation of neural stem cells. Although such mechanisms are not fully known yet, it is hoped that this paper would foster further investigation into the mechanisms of this phenomenon, which accordingly improves human health.

Radiation therapy using electron beams is a promising method due to its physical dose distribution. Monte Carlo (MC) code is the best and most accurate technique for forespeaking the distribution of dose in radiation treatment of patients.
We report an MC simulation of a linac head and depth dose on central axis, along with profile calculations. The purpose of the present research is to carefully analyze the application of MC methods for the calculation of dosimetric parameters for electron beams with energies of 8–14 MeV at a Siemens Primus linac. The principal components of the linac head were simulated using MCNPX code for different applicators.
The consequences of measurements and simulations revealed a good agreement. Gamma index values were below 1 for most points, for all energy values and all applicators in percent depth dose and dose profile computations. A number of states exhibited rather large gamma indices; these points were located at the tail of the percent depth dose graph; these points were less used in in radiotherapy. In the dose profile graph, gamma indices of most parts were below 1. The discrepancies between the simulation results and measurements in terms of Zmax, R90, R80 and R50 were insignificant. The results of Monte Carlo simulations showed a good agreement with the measurements.
The software can be used for simulating electron modes of a Siemens Primus linac when direct experimental measurements are not feasible.

Acute myocardial infarction (MI) accounts for one third of deaths. Cardiac troponin I (TnI) is a reliable biomarker of cardiac muscle tissue injury and is employed in the early diagnosis of MI.
In this study, a molecular method is introduced to early diagnosis of MI by rapid detection of TnI.
The detection method was based on electrochemical aptasensing, being developed using different methods and evaluation steps. A gold electrode was used as a transducer to successful immobilize 76base aptamer to fabricate a TnI biosensor.
The designed aptasensor could detect TnI in a range of 0.03 to 2.0 ng mL-1 without using any label, pre-concentration or amplification steps. The limit of detection was attained as 10 pg mL-1 without significant trouble of interfering species. The TnI biosensor demonestrated a stable, regenerative and reproducible function. 89 human samples were used to evaluate the performance of the TnI biosensor, and it represented 100% and 81%, diagnostic sensitivity and specificity, respectively.
This aptasensor may be used as an applicable tool in the future of early medical diagnosis of MI.

With increasing the usage of myocardial perfusion imaging (MPI) for the diagnosis of ischemic heart disease, we aimed to evaluate the side effects of low-dose radiation induced by this technique on blood elements, especially proteins and liver function factors.
Materials and 40 eligible patients (Mean age: 54.62±10.35, 22 female and 18 male), who had referred to the nuclear medicine department for MPI from May till August 2014, were enrolled in the study. A blood sample was taken from each patient just before and 24 hours after the injection of 740Mbq of Tecnetium-99m Methoxy isobutyl isonitrile (99mTc-MIBI) in the rest phase of the MPI in a reference medical laboratory; blood tests included total protein (TP), albumin (Alb), globulin (Glo), aspartate aminotransferase (AST), alanine transaminase(ALT), alkaline phosphatase (ALP), direct bilirubin (D.Bili), total bilirubin (T.Bili),serum iron (SI), total iron bounding capacity (TIBC), Albumin globulin ratioA/G ratio), and complete blood count (CBC).
Injection of 740Mbq99mTc-MIBI caused a significant increase in serum levels of AST (p= 0.001), ALT (p= 0.001), SI(p= 0.030), TIBC (p= 0.003) and A/G Ratio (p= 0.020). However, following radiotracer injection, a significant decrease was noted in the serum levels of TP (p= 0.002), Alb (p= 0.014), Glo(p= 0.002), ALP(p= 0.001), D.Bili (p= 0.003) and T.Bili(p= 0.000).
Due to increased usage of MPI, our data highlights the importance of monitoring the clinical and paraclinical effects of the procedure on vital organs and physiological pathways to reduce their adverse effects.

Electromagnetic fields (EMF) with different intensities are widely used at home, offices and public places.Today, there is a growing global concern about the effects of human exposure to EMFs. Epilepsy is one of the most common chronic neurological diseases, affecting 50 million people of all ages worldwide. We aimed to investigate the effect of exposure to Wi-Fi radiation on epileptic behavior of rats.
147 male rats, weighing 200-250 g, were divided into seven groups; negative control (no intervention), sham 1(distilled water), positive control (Pentylentetrazol [PTZ]), intervention group 1 (PTZ Wi-Fi “off”), sham 2 (distilled water Wi-Fi “off”), sham 3 (distilled water Wi-Fi “on”), and intervention group 2 (PTZ Wi-Fi “on”). The rats were exposed to Wi-Fi for 2h at a distance of 30cm from a commercial Wi-Fi router. Convulsive behaviors of rats were monitored and scored based on the intensity and type by measuring latency/threshold time, number of convulsions, sum of scores and durations of seizure, and duration of score 6 seizure. Kruskal-Wallis and Mann-Whitney U-tests were used to analyze the data.
Convulsion was observed in interventions Group 4 and Group 7, and positive control. The mean number of events, and sum of scores were significantly different in intervention 2 than other two groups. However, the differences in mean threshold, mean sum of durations and “ time to show convulsion with score 6 ” were not statistically significant (P>0.05).
Due to limitations of our study including the sample size, these findings should be interpreted with caution. In this study, exposure to 2.4 GHz Wi-Fi radiation showed significant beneficial effects on the epileptic behaviour of rats. More experiments are needed to verify if these exposures can be used as a therapeutic approach for amelioration of seizures in epilepsy.

Chronic low back pain (CLBP) disability has been particularly frustrating because its treatment has been a great therapeutic challenge. Disability has been suggested to depend on different factors that should be found and considered in the medical management. The inter-segmental coordination is often impaired in CLBP subjects; however, to the best of our knowledge, there is no evidence about the relationship between the existence of coordination problems and disability in CLBP patients.
To evaluate the correlation between sagittal plane trunk-pelvis inter-segmental coordination parameters during walking and disability level in CLBP patients.
Kinematic data were collected from 16 non-specific CLBP (18-40 years) volunteers during walking. Sagittal plane time-normalized segmental angles and velocities were used to calculate continuous relative phase for each data point. Coordination parameters, mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify the trunk-pelvis coordination pattern and variability during gait cycles, respectively. The disability level was quantified through Oswestry Disability Index (ODI) questionnaire. Pearson correlation coefficient was used to find the probable correlation between coordination parameters and disability level.
The analysis demonstrated a significant correlation between sagittal plane MARP or DP and disability level (%ODI) in CLBP subjects during walking (r= -0.806 P This study demonstrated that the lower the MARP (more in-phase pattern) and DP (less variable pattern) in the CLBP subjects, the more disability existing in such patients. The results suggest that clinicians should look beyond pain management when prescribing rehabilitation for CLBP and consider interventions that target segmental coordination improvement to manage CLBP induced disability.

This work evaluated the efficiency of common ultrasound stimulation (U.S.S) types on bacterial growth in vitro using clinically relevant conditions.
To estimate different frequencies ultrasound bactericidal ability on bacteria in bacteria of Pseudomonas Aeruginosa.
Six types of U.S.S (continuous wave, 7w/cm2, 20 KHz; continuous wave, 35w/0.8L, 40 KHz; continuous wave, 5w/cm2, 1.1 MHz; pulsed wave, 5w/cm2, 3.3 MHz; continuous wave, 5w/cm2, 3.3 MHz and continuous wave, 0.5w/cm2, 3.5 MHz) were applied to a separate set of culture plates containing Pseudomonas aeruginosa for 10 minutes at room temperature on four sample sets to inhibit bacterial growth. After US.S treatment, the zone of inhibition at the US probe location was measured.
Zone of inhibition measurements demonstrated a significant inhibitory effect for continuous wave US.S of 5w/cm2, 1.1 MHz; pulsed wave US.S of 5w/cm2, 3.3 MHz; and continuous wave US.S of 5w/cm2, 3.3 MHz (p The data suggest that for infected wounds, continuous wave US.S of 5w/cm2 and 1.1 MHz; pulsed wave US.S of 5w/cm2 and 3.3 MHz; and continuous wave US.S of 5w/cm2 and 3.3 MHz ultrasound treatments may have an initial bacterial inhibitory effect, which does not significantly change with subsequent treatments.

Deep brain stimulation (DBS) is known as the most effective technique in the treatment of neurodegenerative diseases, especially Parkinson disease (PD) and epilepsy. Relative healing and effective control of disease symptoms are the most significant reasons for the tangible tendency in use and development of this technology. Nevertheless, more cellular and molecular investigations are required to reveal the detailed mechanism of DBS. Here, we reviewed the methods, challenges and the ways to overcome the limitations of DBS. Also, challenges in probe fabrication technology, material selection, related mechanical stability and biocompatibility concerns are discussed. Finally, closed- and open-loop stimulation systems were compared.

The aim of this report is to present a new two-piece thyroid-neck phantom produced by the concurrent use of epoxy resin and poly(methyl methacrylate) (PMMA: plexiglass) soft tissue equivalent materials. Accordingly, mass attenuation coefficients of the epoxy resin and the plexiglass compounds were obtained from simulation (NIST XCOM 3.1) and measurements (practical dosimetry) and compared to those related to human soft tissue (ICRU 44). The thyroid-neck phantom and thyroid gland dimensions were derived from scientific references and the atlas of human anatomy, respectively. The thyroid phantom was designed by CATIA V5R16 software and produced by the epoxy resin compound by three-dimensional printer. Other organs were designed by ProNest software and made by the plexiglass sheets by CNC laser cutting machine. The mass attenuation coefficients for the epoxy resin (50 keV- 20 MeV) and the plexiglass (0-20 MeV) were comparable to human soft tissue (ICRU 44), all with standard relative deviation beneath 5%. In addition, the SPECT images indicated the similarity between human thyroid tissue and its phantom. In conclusion, this study proves the feasibility and reliability of epoxy resin application in the production of two-piece thyroid-neck phantom. This phantom can be applied in the calibration of gamma camera systems, dosimetry and gamma spectrometry in the nuclear medicine field.