Journal of Biomedical Physics and Engineering最新文献

Background: Non-specific chronic low back pain (CLBP) is a common painful condition and is responsible for different physical disorders. Despite alternative therapies, patients still suffer from persistent pain. Repetitive transcranial magnetic stimulation (rTMS) has provided much evidence of pain reduction, but results have not been examined deeply in CLBP symptoms.

Objective: The analgesic effect of rTMS in non-specific CLBP patients was evaluated by the amplitude of low-frequency fluctuation (ALFF) analysis in resting-state fMRI.

Material and methods: In this experimental study, fifteen non-specific CLBP participants (46.87±10.89 years) received 20 Hz rTMS over the motor cortex. The pain intensity and brain functional scan were obtained during pre and post-stimulation for all participants. The ALFF maps of the brain in two scan sessions were identified and the percentage of pain reduction (PPR%) was determined using paired t-test. Also, correlation analysis was used to find a relationship between ALFFs and pain intensity.

Results: Pain intensity was significantly reduced after induced-rTMS in non-specific CLBP (36.22%±13.28, P<0.05). Positive correlation was found between ALFF in the insula (INS) and pain intensity (r_pre-rTMS=0.59, r_post-rTMS=0.58) while ALFF in medial prefrontal cortex (mPFC) and pain intensity had negatively correlated (r_pre-rTMS=-0.54, r_post-rTMS=-0.56) (P<0.05). ALFF increased in mPFC while INS, thalamus (THA), and supplementary motor area (SMA) showed decremental ALFF followed by rTMS.

Conclusion: This study demonstrated that ALFF in INS, THA, mPFC, and SMA is associated with CLBP symptoms and analgesic effects of rTMS. ALFF potentially seems to be a proper objective neuroimaging parameter to link spontaneous brain activity with pain intensity in non-specific CLBP patients.

Background: One of the main reasons for neonatal deaths is preterm delivery, and infants who have survived preterm birth (PB) are at risk of significant health complications. However, an effective method for reliable and accurate prediction of preterm labor has yet to be proposed.

Objective: This study proposes an artificial neural network (ANN)-based approach for early prediction of PB, and consequently can hint physicians to start the treatment earlier, reducing the chance of morbidity and mortality in the infant.

Material and methods: This historical cohort study proposes a feed-forward ANN with 7 hidden neurons to predict PB. Thirteen risk factors of PB were collected from 300 pregnant women (150 with preterm delivery and 150 normal) as the ANN inputs from 2018 to 2019. From each group, 70%, 15%, and 15% of the subjects were randomly selected for training, validation, and testing of the model, respectively.

Results: The ANN achieved an accuracy of 79.03% for the classification of the subjects into two classes normal and PB. Moreover, a sensitivity of 73.45% and specificity of 84.62% were obtained. The advantage of this approach is that the risk factors used for prediction did not require any lab test and were collected in a questionnaire.

Conclusion: The efficacy of the proposed approach for the early identification of pregnant women, who are at high risk of preterm delivery, leads to necessary care and clinical interventions, applied during the pregnancy.

Background: The duration of orthodontic treatment is often a significant deterrent for patients when considering conventional mechanics, which can be time-consuming. Photobiomodulation (PBM) utilizes visible red to near-infrared wavelengths of light frequencies to expedite orthodontic treatment time.

Objective: To investigate the effect of three Light Emitting Diode (LED) frequencies and their heat generation on soft tissues in accelerating tooth movement through Finite Element Method (FEM) study.

Material and methods: In this FEM study, a three-dimensional FEM model of the skull of a male patient with mild to moderate crowding in the maxilla, and mandible. The dentitions were scanned using a Computed Tomography (CT). A static force of 70 gm on the anterior region of the maxilla and mandible was applied from the labial sides, and a second static analysis was carried out by using both a 70 gm of force and thermal load with three different frequencies of 740, 850, and 940 nm on the 1^st and 3^rd quadrants. The effect of LED application and heat generation was assessed on soft tissues in bringing faster orthodontic tooth movement.

Results: Increased tooth movement with combined loading case in the 1^st and 3^rd quadrants when compared with the 2^nd and 4^th quadrants. The temperature distribution was higher at 940 nm followed by 740 & 850 nm of frequency.

Conclusion: Faster movements were observed in the combined loading case in the 1^st and 3^rd quadrants compared to static loading in other quadrants. Heat generation was higher with 940 nm frequency followed by 740 and 850 nm.

Background: Patients with experienced stroke have suffered from long-term disability, especially in their distal upper extremities. Physiotherapy programs are considered a proper treatment to overcome the complications caused by stroke. The use of robots in physiotherapy is also considered a newfound procedure as an alternative to conventional methods.

Objective: This study aimed to describe a feasibility test on a physiotherapy robot and evaluate the efficacy of the proposed device.

Material and methods: In this experimental study, a 4-degrees-of-freedom robot was designed and fabricated for hand physiotherapy, which was tested on 17 and 4 post-strokes in the passive and active modes for the best efficiency. Additionally, the patient's hand spasticity was measured according to the Modified Ashworth Scale pre- and post-usage of the device.

Results: A total of 12 of 17 individuals could do the exercises and follow the instructions without any problem, and 8 of 12 individuals had a decrease in their spasticity. All 4 patients in active-assisted mode could fulfill the activity.

Conclusion: Physiotherapy based on a robot-assisted is considered a promising method with effective treatments for post-stroke patients, which can be a good alternative to routine methods of physiotherapy. However, more tests are needed to determine the rate of functions' restoration.

The search for extraterrestrial intelligence is a fascinating and important endeavor, but it raises significant ethical and safety concerns. In the search for extraterrestrial intelligence, scientists use knowledge of physics to identify potential communication methods and signals that may be used by extraterrestrial civilizations. One of the most notable scientists to highlight these concerns was the late physicist Stephen Hawking, who cautioned that actively attempting to communicate with extraterrestrial civilizations could harm humanity. While it is true that we cannot predict the intentions of any potential extraterrestrial civilizations, some scientists argue that the potential advantages of seeking contact outweigh the potential risks. Deciding to initiate contact with extraterrestrial civilizations is a complex issue that requires balancing scientific curiosity with concerns for our own safety. The "Intelligence Trap" is a concept in psychology that suggests that highly intelligent people are more susceptible to cognitive biases and flawed thinking than less intelligent people. It can be argued that Hawking's warnings may be an example of the so-called intelligence trap, as some evidence from the field of physics suggests. Nonetheless, Hawking emphasized that it is crucial for scientists and policymakers to carefully weigh the potential risks and benefits of such efforts and proceed with caution.

Background: In radiology, optimizing radiation protection is crucial, and field collimation plays a critical role in minimizing patient dose. As technology has evolved, electronic collimation has become the preferred method due to its effectiveness in digital imaging systems, replacing traditional film-screen systems.

Objective: The current study aimed to investigate the prevalence of cropping in digital radiography and its potential impact on patient radiation dose because of improper collimation practices.

Material and methods: This retrospective analysis was conducted on digital X-ray machine images. Quality control tests were performed to ensure equipment accuracy, and image cropping was then measured by analyzing archived images. Finally, the cropped image fraction and associated unnecessary radiation doses were calculated.

Results: Quality control tests confirmed that all imaging equipment was functioned within acceptable alignment and angle tolerances. The analysis of 911 images revealed a high prevalence of cropping (82%), with significant variation across different projections. Lateral knee images exhibited the highest cropping rate (96.2%), while abdominal images had the lowest (36.1%).

Conclusion: Electronic image cropping can lead radiologic technologists to inaccurately define the primary radiation field, affecting image quality and potentially increasing patient radiation exposure. Based on the obtained results, proper collimation can reduce the average Dose Area Product (DAP) by 29.01%. This approach not only enhances patient safety but also minimizes unnecessary radiation exposure and potentially reduces healthcare costs.

Background: A key challenge in steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) systems is to effectively recognize frequencies within a short time window. To address this challenge, the specific characteristics of the data are needed to select the frequency recognition method. These characteristics include factors, such as the number of stimulation targets and the presence of harmonic frequencies, resulting in optimizing the performance and accuracy of SSVEP-based BCI systems.

Objective: The current study aimed to examine the effect of data characteristics on frequency recognition accuracy.

Material and methods: In this analytical study, five commonly used frequency recognition methods were examined, used to various datasets containing different numbers of frequencies, including sub-data with and without frequency harmonics.

Results: The increase in the number of frequencies in the Multivariate Linear Regression (MLR) method has led to a decrease in frequency recognition accuracy by 9%. Additionally, the presence of harmonic frequencies resulted in an 8% decrease in accuracy for the MLR method.

Conclusion: Frequency recognition using the MLR method reduces the effect of the number of different frequencies and harmonics of the stimulation frequencies on the frequency recognition accuracy.

Background: Fibroblast Activation Protein (FAP)-targeted nanoparticles (NPs) are designed to accumulate in cancerous stroma. These NPs hold promise for imaging applications in cancer therapy.

Objective: This systematic review aimed to comprehensively explore the use of FAP-targeting NPs for cancer diagnosis through different imaging modalities.

Material and methods: This systematic review followed the framework proposed by O'Malley and Arksey. Peer-reviewed studies were searched in the Scopus, Science Direct, PubMed, and Google Scholar databases. Eligible studies were selected, and data were extracted to investigate the FAP-targeting NPs in imaging. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was also utilized to present the results.

Results: Five studies met the specified inclusion criteria and were finally selected for analysis. The extracted data was classified into two categories: general and specific data. The general group indicated that most studies have been conducted in Mexico and have increased since 2022, and the specific group showed that colorectal cancer and Nude mice have received the most research attention. Furthermore, FAP-targeted NPs have demonstrated superior diagnostic imaging capabilities, even compared to specific methods for each cancer type. Also, they have been safe, with no toxicity.

Conclusion: FAP-targeted NPs using different ligands, such as Fibroblast Activation Protein Inhibitor (FAPI), can accurately detect tumors and metastases, and outperform specific cancer peptides like PSMA in cancer diagnosis. They are also non-toxic and do not cause radiation damage to tissues. Therefore, FAP-targeted NPs have the potential to serve as a viable alternative to FAP-targeted radionuclides for cancer diagnosis.

Background: High-quality images with minimum radiation dose are considered a challenge in Computed Tomography (CT) scans.

Objective: The current study aimed to assess the efficacy of the Iterative Reconstruction in Image Space (IRIS) algorithm combined with Automatic Tube Current Modulation (ATCM) compared to Filtered Back Projection (FBP) in brain CT scans.

Material and methods: In this cross-sectional study, 200 patients underwent to brain CT scan, and images were then reconstructed using both FBP and IRIS. The CT Number (CTN), noise, and Signal-to-Noise Ratio (SNR) were computed for different tissues from CT images. The performance of two algorithms under different exposure conditions was evaluated using a water phantom. Two experienced radiologists assessed the image quality. Volume CT Dose Index (CTDI_vol) and Dose Length Product (DLP) were recorded for each scan.

Results: FBP reconstruction exhibited higher noise and lower SNR compared to IRIS, both with and without ATCM. Noise levels significantly increased for FBP combined with ATCM. Subjective analysis showed higher performance for IRIS without ATCM compared to other approaches. The mean CTDI_vol with and without ATCM was 20.04±3.33 and 36.37±4.65 mGy, respectively. In the phantom study, the noise with IRIS remained lower than that with FBP even with a 42% dose reduction.

Conclusion: IRIS algorithm can preserve the image quality when radiation dose is significantly reduced by ATCM in brain CT scan. Implementation of IRIS combined with ATCM is recommended for brain CT examinations.

Background: The knee joint must adapt to the changes in walking speed to stabilize the stance phase and provide fluency in the swing phase.

Objective: This study aimed to report a comparison of the gait patterns of transfemoral amputees using a novel mechanical prosthetic knee that can adapt automatically to different walking speeds with 3R60 and 3R15 knee prostheses.

Material and methods: In this experimental study, biomechanical data were collected from six unilateral trans-femoral amputees walking with three knee prostheses. Gait data were gathered at slow, normal, and fast walking speeds across a 7-meter walkway using the Vicon motion system.

Results: The results revealed a significant difference in knee angular velocity during the swing phase between prosthetic knees across three walking speeds (P-value=0.002). Prosthetic knee flexion decreased significantly by increasing walking speed for the novel mechanical auto-adaptive prosthetic knee (P-value<0.001). A lower value of hip power during early swing was considered when amputees walked with novel knee prosthesis (P-value<0.00). The intact leg ankle plantar flexion angle or vaulting did not significantly change while walking speed increased in the novel knee prostheses compared to walking with the 3R60 and 3R15 knee prostheses (P-value=0.002 and P-value<0.06, respectively).

Conclusion: Based on the results, a novel mechanical auto-adaptive knee prosthesis has advantages compared to the other conventional designs for unilateral trans-femoral amputees walking at different speeds.