Journal of Biomedical Physics and Engineering最新文献

Background: The effect of different types of substances on brain function is still challenging; however, many studies have shown the functional and structural damage to the brain under influence of substance abuse.

Objective: This study aimed to quantitatively compare the effect of opioid (Op), methamphetamine (Meth), cannabis (Can), and simultaneous methamphetamine and opioid (Multi-Drug (MD)) abuse on brain function. Furthermore, the impacts of pure Op and Meth abuse were considered with simultaneous substance abuse.

Material and methods: In this descriptive study, the electroencephalogram (EEG) signal was recorded from 52 participants in the Meth, Op, Can, and MD abusers, and the Healthy Control (HC) groups at rest state. EEG data were analyzed on the frequency domain with electrode-based, cortex-based, and hemisphere-based approaches.

Results: However, the power spectrum in the delta band in the Op group, the gamma band in the Can group, and the gamma and beta bands in the MD group more significantly increased compared to the HC group, the power spectrum values in the Meth group reduced in the alpha, beta, and gamma bands. Moreover, the power spectrum values in the MD group more significantly higher than the Meth and Op groups in the beta and gamma bands.

Conclusion: Since substance abuse in different types caused various changes in frequency components, the different power spectrum bands analysis in abusers can be reasonable to apply as a biomarker to detect the drug types.

Background: Eye melanoma is deforming in the eye, growing and developing in tissues inside the middle layer of an eyeball, resulting in dark spots in the iris section of the eye, changes in size, the shape of the pupil, and vision.

Objective: The current study aims to diagnose eye melanoma using a gray level co-occurrence matrix (GLCM) for texture extraction and soft computing techniques, leading to the disease diagnosis faster, time-saving, and prevention of misdiagnosis resulting from the physician's manual approach.

Material and methods: In this experimental study, two models are proposed for the diagnosis of eye melanoma, including backpropagation neural networks (BPNN) and radial basis functions network (RBFN). The images used for training and validating were obtained from the eye-cancer database.

Results: Based on our experiments, our proposed models achieve 92.31% and 94.70% recognition rates for GLCM+BPNN and GLCM+RBFN, respectively.

Conclusion: Based on the comparison of our models with the others, the models used in the current study outperform other proposed models.

Background: Magnetic resonance spectroscopy (MRS) is a non-invasive diagnostic and the neuroimaging method of choice for the noninvasive monitoring of brain metabolism in patients with glioma tumors. ¹H-MRS is a reliable and non-invasive tool used to study glioma. However, the metabolite spectra obtained by ¹H-MRS requires a specific quantification procedure for post-processing. According to our knowledge, no comparisons have yet been made between spectrum analysis software for quantification of gliomas metabolites.

Objective: Current study aims to evaluate the difference between this two common software in quantifying cerebral metabolites.

Material and methods: In this analytical study, we evaluate two post-processing software packages, java-based graphical for MR user interface packages (jMRUI) and totally automatic robust quantitation in NMR (TARQUIN) software. ¹H-MRS spectrum from the brain of patients with gliomas tumors was collected for post-processing. AMARES algorithms were conducted to metabolite qualification on jMRUI software, and TARQUIN software were implemented with automated quantification algorithms. The study included a total of 30 subjects. For quantification, subjects were divided into a normal group (n=15) and group of gliomas (n=15).

Results: When calculated by TARQUIN, the mean metabolites ratio was typically lower than by jMRUI. While, the mean ratio of metabolites varied when quantified by jMRUI vs. TARQUIN, both methods apparent clinical associations.

Conclusion: TARQUIN and jMRUI are feasible choices for the post-processing of cerebral MRS data obtained from glioma tumors.

Background: Previous studies shown that mobile phone can impairment of working memory in humans.

Objective: In this study, the effect of radiofrequency radiation emitted from common mobile jammers have been studied on the learning and memory of rats.

Material and methods: In this prospective study, 90 Sprague-Dawley rats, were divided into 9 groups (N=10): Control, Sham^1st (exposed to a switched-off mobile jammer device at a distance of 50 or 100 cm/1 day, 2 hours), Sham^2nd (similar to Sham^1st, but for 14 days, 2 h/day), Experimental^1st -50 cm/1 day &100 cm/1 day (exposed to a switched-on device at a distance of 50 or 100 cm for 2 hours), Experimental^2nd (similar to experimental^1st, but for 14 days, 2 h/day). The animals were tested for learning and memory the next day, by the shuttle box. The time that a rat took to enter the dark part was considered as memory.

Results: Mean short-term memory was shorter in the experimental- 50 cm/1 day than control and sham- 50 cm/1 day (P=0.034), long-term memory was similar. Mean short- and long-term memory were similar in the experimental- 100 cm/1 day, control and sham- 100 cm/1 day (P>0.05). Mean short-term memory was similar in experimental- 50 cm/14 days, control, and sham- 50 cm/14 days (P=0.087), but long-term learning memory was shorter in the radiated group (P=0.038). Mean short- and long-term were similar among experimental-100 cm/14 days, control or sham 100 cm/14 days (P>0.05).

Conclusion: Rats exposed to jammer device showed dysfunction in short- and long-term memory, which shown the unfavorable effect of jammer on memory and learning. Our results indicated that the distance from radiation source was more important than the duration.

Background: Breast hypertrophy is a significant health problem with both physiological and psychological impacts on the patients' lives. Patients with macromastia adopt a corrective posture due to the effect of the breast on the center of gravity and possibly in a subconscious effort to conceal their breasts.

Objective: This study aimed to evaluate whether the posture of patients with macromastia changed after the reduction of mammoplasty.

Material and methods: In this prospective study, patients with breast cup sizes C, D, and DD were scheduled for reduction mammoplasty in 3 Shiraz University Hospitals. Age, weight, height, and preoperative cup sizes of the breasts were recorded for every patient, and all patients underwent posture analysis with forceplate before and after reduction mammoplasty. Finally, the preoperative and postoperative data were compared.

Results: Mean age at the time of reduction mammaplasty was 43.57±9.1; the mean pre-operation, such as weight, height, and mean the body mass index (BMI) was 76.57±10 kg, 158.28±6 cm and 30.57±4.1, respectively. The average Anterior-posterior (AP) direction velocity before and after the surgery was 0.85±0.12 cm/s and 0.79±0.098, respectively. These values were 0.83±0.09 and 0.81±0.10 for the mediolateral direction. The Detrended Fluctuation Analysis (DFA) value for the AP direction was 1.63±0.3 and 1.60±0.2 for pre-and post-surgery, respectively, which was not statistically different. The DFA value for maximum likelihood (ML) direction was 1.65±0.2 and 1.48±0.2 in pre-op and post-op, respectively, which was statistically significantly different.

Conclusion: Reducing the weight of enlarged breasts can correct disturbed sagittal balance and postural sway.

Background: Current evidence in low back pain (LBP) focuses on population averages and traditional multivariate analyses to find the significant difference between variables. Such a focus actively obscured the heterogeneity and increased errors. Cluster analysis (CA) addresses the mentioned shortcomings by calculating the degree of similarity among the relevant variables of the different objects.

Objective: This study aims to evaluate the agreement between the treatment-based classification (TBC) system and the equivalent 3 cluster typology created by partitioning around medoids (PAM) analysis.

Material and methods: In this cross-sectional study, a convenient sample of 90 patients with low back pain (50 males and 40 females) aged 20 to 65 years was included in the study. The patients were selected based on the 21 criteria of 2007 TBC system. An equivalent 3 cluster typology (C3) was applied using PAM method. Cohen's Kappa was run to determine if there was agreement between the TBC system and the equivalent C3 typology.

Results: PAM analysis revealed the evidence of clustering for a C3 cluster typology with average Silhouette widths of 0.12. Cohen's Kappa revealed fair agreement between the TBC system and C3 cluster typology (Percent of agreement 61%, Kappa=0.36, P<0.001). Selected criteria by PAM analysis were different with original TBC system.

Conclusion: Higher probability of chance agreement was observed between two classification methods. Significant inhomogeneity was observed in subgroups of the 2007 TBC system.

Background: It is needed to minimize the effect of flow direction on the desired area, such as arterial input function (AIF) in magnetic resonance imaging (MRI).

Objective: The current study aimed to investigate the effect of flow direction on different velocities (0-80.39 cm/s) for the strength of the signal intensity (SI) at the linear phase-encoding (LPE) and the center out phase-encoding (COPE) schemes and to recommend the best flow direction in a selected slice and scheme for absolute perfusion measurement by inversion recovery T1-weighted turbo fast low-angle shot (TurboFLASH) MR images.

Material and methods: In this experimental study, the flow rates were measured using a flow phantom, and the signal intensity (SI) was measured at the two opposite flow directions in the Z-axis perpendicular to the coronal image at a concentration of 0.8 mmol/L of gadolinium-diethylenetriaminepantaacetic acid (Gd-DTPA) by using the LPE and COPE schemes.

Results: The increase in velocity along with the growth in SI and inflow affected the use of LPE and COPE acquisitions in both directions. The velocity of the arterial input function is needed to calculate the inflow correction factor by using two schemes in two opposite flow directions to investigate perfusion.

Conclusion: The COPE scheme was better than the LPE scheme in measuring perfusion since the velocity and direction of blood flow affect SI less.

Background: Mobility of lung tumors is induced by respiration and causes inadequate dose coverage.

Objective: This study quantified lung tumor motion, velocity, and stability for small (≤5 cm) and large (>5 cm) tumors to adapt radiation therapy techniques for lung cancer patients.

Material and methods: In this retrospective study, 70 patients with lung cancer were included that 50 and 20 patients had a small and large gross tumor volume (GTV). To quantify the tumor motion and velocity in the upper lobe (UL) and lower lobe (LL) for the central region (CR) and a peripheral region (PR), the GTV was contoured in all ten respiratory phases, using 4D-CT.

Results: The amplitude of tumor motion was greater in the LL, with motion in the superior-inferior (SI) direction compared to the UL, with an elliptical motion for small and large tumors. Tumor motion was greater in the CR, rather than in the PR, by 63% and 49% in the UL compared to 50% and 38% in the LL, for the left and right lung. The maximum tumor velocity for a small GTV was 44.1 mm/s in the LL (CR), decreased to 4 mm/s for both ULs (PR), and a large GTV ranged from 0.4 to 9.4 mm/s.

Conclusion: The tumor motion and velocity depend on the tumor localization and the greater motion was in the CR for both lobes due to heart contribution. The tumor velocity and stability can help select the best technique for motion management during radiation therapy.

Background: The paradigm shifts in target theory could be defined as the radiation-triggered bystander response in which the radiation deleterious effects occurred in the adjacent cells.

Objective: This study aims to assess bystander response in terms of DNA damage and their possible cell death consequences following high-dose radiotherapy. Temporal characteristics of gH2AX foci as a manifestation of DNA damage were also evaluated.

Material and methods: In this experimental study, bystander response was investigated in human carcinoma cells of HeLa and HN5, neighboring those that received high doses. Medium transfer was performed from 10 Gy-irradiated donors to 1.5 Gy-irradiated recipients. GammaH2AX foci, clonogenic and apoptosis assays were investigated. The gH2AX foci time-point study was implemented 1, 4, and 24 h after the medium exchange.

Results: DNA damage was enhanced in HeLa and HN5 bystander cells with the ratio of 1.27 and 1.72, respectively, which terminated in more than two-fold clonogenic survival decrease, along with gradual apoptosis increase. GammH2AX foci temporal characterization revealed maximum foci scoring at the 1 h time-point in HeLa, and also 4 h in HN5, which remained even 24 h after the medium sharing in higher level than the control group.

Conclusion: The time-dependent nature of bystander-induced gH2AX foci as a DNA damage surrogate marker was highlighted with the persistent foci at 24 h. considering an outcome of bystander-induced DNA damage, predominant role of clonogenic cell death was also elicited compared to apoptosis. Moreover, the role of high-dose bystander response observed in the current work clarified bystander potential implications in radiotherapy.