Journal of Biomedical Physics and Engineering最新文献

The largest universal immunization in history has occurred as a result of the COVID-19 pandemic. The developed COVID-19 vaccines have been shown to provide protection against severe forms of COVID-19 by inducing anti-spike neutralizing antibodies. It has been found that individuals who have not been vaccinated against COVID-19 were more likely to contract the virus during a period when the Delta variant was dominant, as compared to those who have received the complete dose of the vaccine, irrespective of the variant. However, there is no notable disparity in the likelihood of hospitalization, requirement for mechanical ventilation, or mortality between the two groups once infected. Nevertheless, those who are unvaccinated may require additional oxygen support. There are reports indicating unfavorable health effects, ranging from transient thyroid dysfunction to death following vaccination. In addition, some people are susceptible to SARS-CoV-2 infection despite they have immunized with the COVID-19 vaccine. Given all these considerations, several key factors should be better understood and considered to enable us to even more successfully manage future pandemics breakthrough infections. The effectiveness of physical treatment methods, e.g., Low Dose Radiation Therapy (LDRT) should be compared to pharmacological treatments.

Background: The Electromagnetic Field (EMF) effect is considered an alarming human health issue, dependent on the use of mobile phones. Several nationwide awareness programs on EMF Emissions & Telecom Towers were initiated by the Department of Telecom (DoT) to build a direct bridge between the number of investors and the information gap with scientific evidence. EMF interaction with humans has caused oxidative stress for brain physiological and pathological degeneration.

Objective: This study aimed to investigate the EMF's influence on oxidative stress and disorders of neurodegenerative.

Material and methods: This analytical study is conducted on a generalized linear model, a supervised learning approach in machine learning, to understand mobile tower radiation. The data is obtained from open sources from two different states in India.

Results: Confidential Interval (CI) was obtained for measured value radiation for Andhra Pradesh in 2018-2019 as 95% CI [0.0045 to 0.0111] and for 2019-2020 as 95% CI [0.0016 to 0.0028]. Telangana -CI for Measured Value (MV) in 2018-2019 was found to be 95% CI [0.0500 to 0.0763] and 2019-2020 is 95% CI [0.0189 to 0.4345].

Conclusion: Generalized Linear Models (GLM) are the best statistical model to analyze the mobile tower radiation.

Background: Ultrasound waves are considered non-invasive, safe, and mechanical stimuli with unknown mechanisms.

Objective: The aim of this study is to determine the effect of acoustic cavitation interaction according to the mechanical index (MI) on fibroblast cells' reproducibility and gene expression of collagen Ι as a skin repair agent.

Material and methods: In this interventional study, the ultrasonic pressure equations were solved to extracted the maximum mechanical indices with frequencies of 150 kHz, 40 kHz, 28 kHz and low intensity (<0.5 W/cm²). Groups were extracted with a mechanical index of 0.10, 0.20, and 0.40. Then, fibroblast cells were exposed to selected acoustic parameters from simulation. After 5 days, the proliferation was measured with an MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay, and collagen Ι expression was quantified.

Results: Increasing reproducibility in the groups of 0.23 W/cm² with 0.20 mechanical index threshold was calculated at 1.70±0.05 and 1.07±0.04 times higher in continuous and pulse modes compared to the control group. Reducing the proliferation in group 0.40 mechanical index was shown as compared with control and sham groups in pulse mode (P-value<0.05). The collagen Ι expression level of fibroblast cells in groups of control and 0.20 MI were 0.03±0.00 and 0.17±0.05, respectively. The acoustic vibration effects at 0.20 mechanical index have promoted fibroblast cell functions.

Conclusion: Low-frequency and -intensity ultrasound waves on the mechanical index threshold (cavitation threshold) increases the proliferation of fibroblast cell and the expression of collagen type Ι.

Background: The reduction of patient radiation dose in coronary Computed Tomography Angiography (CCTA) with acceptable image quality is considered an important factor in the research.

Objective: This study aims to optimize the CCTA protocol using a retrospective Electrocardiogram (ECG)-gated axial scan protocol in patients with different Body Mass Indexes (BMIs).

Material and methods: In this cross-sectional study, 66 patients into three main groups: 80 kVp (Group A), 100 kVp (Group B), and 120 kVp (Group C), underwent CCTA. Each group was then divided into two subgroups of BMI<25 and >25 kg/m². Image noise, mean vascular attenuation at the aorta, signal-to-noise ratio (SNR), and Contrast-to-Noise Ratio (CNR) at five regions of coronary arteries, in which Coronary artery anomalies are common were qualitatively evaluated by subjective image quality analysis.

Results: At each kVp, there were no significant differences in CNR, SNR, noise level, and the effective dose between BMI>25 kg/m² and BMI<25 kg/m². The effective radiation dose of groups A, B, and C were 4.16, 8.46, and 14.3 mSv, respectively. Subjective image quality assessment scores were 3.18, 3.5, and 3.73 out of 4 in groups A, B, and C, respectively.

Conclusion: Patient radiation dose using retrospective ECG-gated CCTA can be reduced by about 70% at 80 kVp, which is almost close to the prospective CCTA dose ranges. The retrospective CCTA at 80 kVp can be optimized even in overweight patients (BMI>25 kg/m²).

Background: Magnetic Resonance Imaging (MRI) has become a complementary imaging method for the treatment planning process due to the limitations of Computed Tomography (CT) imaging.

Objective: This study aimed to assess the effect of co-registered MRI and CT (MRI/CT)-based target delineation on the dose to the target, small bowel, bladder, and femoral heads during Helical Tomotherapy (HT).

Material and methods: In this cross-sectional prospective study, MRI in a prone position were obtained for 12 patients with rectal cancer at one-day intervals with simulation CT. Following the co-registration process with the deformable algorithm, target volumes are defined. Gross Tumor Volume (GTV), Clinical Target Volume (CTV), and Planning Target Volume (PTV) were delineated for each CT and MRI/CT.

Results: GTV, CTV, and PTV mean values were significantly higher in the CT-based target delineation method than those in the MRI/CT-based method. In MRI/ CT-based plans, the mean HI value was significantly lower, and the mean Conformity Index (CI) value was significantly higher than that in CT-based plans. In a small bowl, the most of dosimetric parameters (D_max, D_mean, D_50%, D_50%, V_40%, and V_45%) were significantly higher for the CT-based plans. In the bladder, all dosimetric parameters, except V_30%, were statistically higher in CT-based plans.

Conclusion: Co-registered MRI/CT-based treatment planning can produce better dose coverage for the target and reduce the delivered dose to the Organs at Risk (OARs) when compared to CT-based planning.

Background: Dental amalgam is a popular restorative material used in posterior teeth. Hair dryers can emit electromagnetic fields (EMFs) that may affect the microleakage of the amalgam-tooth interface.

Objective: The aim of this experimental study was to investigate whether the EMFs produced by commercial hair dryers could cause microleakage in amalgam restorations.

Material and methods: In this experimental study, a total of 100 human extracted teeth without cavities were selected and prepared for class V preparations on their buccal aspects. The teeth were divided into five groups (G1-G5), each containing 20 teeth. Group 1 served as the control group and was not subjected to any treatment. Groups 2 to 5 were exposed to EMFs of a hair dryer (2000 W, 220 V, and 50 Hz). Groups 2 and 3 were exposed to "EMFs +Hot Air" for 20 min at 10 cm and 30 min at 5 cm, respectively. Groups 4 and 5 were exposed to "EMFs +Cool Air" for 20 min at 10 cm and 30 min at 5cm, respectively. After preparation, the sectioned teeth were evaluated for microleakage using dye penetration measurement.

Results: The microleakage scores showed a significant difference among the three exposure groups (G2, G3, and G5) and the control group (P=0.001, 0.002, and 0.01, respectively). However, there was no significant difference between G4 and G1. The microleakage score in G2 was higher than that in G4.

Conclusion: This study suggests that the common use of hair dryers can lead to damage in amalgam restorations.

Uneven illumination correction is considered a critical pre-processing step in creating digital images from optical microscopes, particularly in whole-slide imaging (WSI). While deep learning-based methods have suggested new possibilities, they often struggle with generalizing to unseen images and require substantial computational resources. The most common approach for training deep neural networks in this field relies on patch-based processing, which may overlook the global illumination distribution, leading to inconsistencies in correction. This study aimed to identify a key limitation in deep learning models for uneven illumination correction, highlighting the importance of preserving the original image resolution and incorporating a global view of illumination patterns to enhance generalization. To address this, we proposed a new training set design strategy that optimizes neural network performance while utilizing computational resources effectively. Our approach ensures a more uniform correction across entire WSI slides, reducing artifacts and improving image consistency. The proposed strategy enhances model robustness and scalability, making deep learning-based illumination correction more practical for clinical and research applications.

Background: The pharmaceutical residues and their metabolites in water, even at low concentrations, is of concern due to their effects on the aquatic environment.

Objective: The current study aimed to investigate the photocatalytic degradation of paracetamol and cefixime trihydrate drugs from aqueous media using nanocomposites.

Material and methods: In this experimental study, the photocatalytic degradation of paracetamol and cefixime trihydrate drugs have been investigated using Fe₂O₃-ZnO and Fe₂O₃-ZnO/Ag nanocomposites. XRD, FESEM, EDS, elemental mapping (e-mapping) and UV-Visible analysis were used to characterize the nanocomposites.

Results: The photocatalytic performance efficiency of Fe₂O₃-ZnO and Fe₂O₃-ZnO/Ag nanocomposites was 45% and 72%, respectively, for paracetamol in 180 min. However, the photocatalytic performance efficiency of Fe₂O₃-ZnO and Fe₂O₃-ZnO/Ag nanocomposites for the degradation of cefixime trihydrate was 38% and 55%, respectively during 60 min.

Conclusion: Fe₂O₃-ZnO and Fe₂O₃-ZnO/Ag nanocomposites demonstrated effective photocatalytic performance in the removal of paracetamol and cefixime trihydrate drugs.

Background: High-intensity focused ultrasound (HIFU) therapy is an effective minimally invasive treatment technique.

Objective: This work aimed to present a theoretical foundation for transient cavitation control in HIFU treatment and investigate cavitation bubbles in multi-frequency ultrasound.

Material and methods: In this theoretical study, the nonlinear vibrations of bubbles in different mediums (water, urine, kidney, and muscle) were simulated using Gilmore-Akulichev and modified Keller-Miksis equations. The dynamic changes of bubble radius during irradiation by multi-frequency combined ultrasound were analyzed, and the effects of multi-frequency ultrasound combinations and frequency differences on the maximum and minimum values of bubble expansion radius and bubble collapse time were investigated.

Results: At the same highest frequency, the triple-frequency produced the largest bubble expansion radius (R_max) while the single-frequency resulted in the smallest bubble expansion radius (R_min). At the same lowest frequency, the single-frequency had the biggest bubble expansion radius and the triple-frequency had the smallest bubble expansion radius. Compared to the combination with a large frequency difference at high frequency, the triple-frequency combination with a small frequency difference at low frequency exhibited a noticeably larger R_max, but R_min showed the opposite behavior. R_max/R_min decreased for the same ultrasonic combination when the medium viscosity increased. The bubble expansion radius ratio R_max/R_min was positively correlated with the bubble collapse time.

Conclusion: There was a strong correlation between the frequency difference and the multi-frequency ultrasound combination and the maximum and minimum values of the cavitation bubble radius and the collapse time.

Background: Patients with Lunotriquetral Interosseous Ligament (LTIL) injuries often experience wrist pain and carpal instability, resulting in challenging treatment. The optimal surgical approach has to be determined for addressing this condition.

Objective: The current study aimed to assess the postoperative outcomes of orthopedic devices in lunotriquetral fixation using a 3D model.

Material and methods: This computer simulation study aimed to develop a three-dimensional model of a normal wrist joint. The study then simulated LTIL tears and compared three surgical methods for fusing the lunate and triquetrum bones using a pin, a screw, and a combination of both.

Results: Based on normal mechanistic behavior in terms of anteroposterior and mediolateral displacement of the lunate bone, the results are presented. However, the use of pin-fixation is significantly superior to the other methods with a displacement of 1.65 and 1.47 mm in fixation versus 0.32 and 0.64 mm in normal anatomy. This approach also significantly decreased the stress on the lunate bone and showed the least stress on the orthopedic device compared to other surgical approaches. For the triquetrum bone, pin fixation proved superior in controlling anteroposterior and vertical motions. This method also imposed significantly less stress on the triquetrum compared to using a screw or double instrumentation.

Conclusion: Lunotriquetral fusion can be achieved using a pin, which provides better results than fusion with a screw or the combined use of a screw and pin.