Journal of Biomedical Physics and Engineering最新文献

Daily calibration of spirometry devices plays an important role in promoting the accuracy of pulmonary diagnostic results. It is needed to have more precise and adequate instruments for calibrating spirometry during the clinical use. In this work, a device was designed and developed based on a calibrated-volume syringe and an electrical circuit was also built to measure the air flux. Some colored tapes with specific size and order covered the syringe piston. When the piston moved in front of the color sensor, the input air flow was calculated according to the width of the strips and transferred to the computer. A Radial Basis Function (RBF) neural network estimator used new data to modify the previous estimation function for increasing the accuracy and the reliability. The simulation showed that the root mean square of the error improved from 13.7±0.37% to 4.2±0.22%, i.e. the calibration curve has improved about 70%.

Background: Surgery and radiotherapy are two main modalities of breast cancer treatment. However, surgery affects the tumor microenvironment negatively and promotes the growth of possible malignant cells remaining in the tumor bed.

Objective: The present study aimed to investigate the effects of intraoperative radiotherapy (IORT) on the tumor microenvironment. Therefore, the effect of surgical wound fluid (WF), collected from operated and irradiated patients on the growth and motility of a breast cancer cell line (MCF-7) was assessed.

Material and methods: In this experimental study, preoperative blood serum (PS) and secreted WF from 18 patients who underwent breast-conserving surgery (IORT-) and 19 patients who received IORT following surgery (IORT+) were collected. The samples were purified and added to MCF-7 cultures. Two groups of the cells were treated with and without fetal bovine serum (FBS) and used as positive and negative controls. Applying 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and scratch wound healing assays, the growth and motility of MCF-7 cells were measured.

Results: Cell growth of the cells receiving WF from IORT+ patients (WF+) was statistically higher than the corresponding values of the cells received PS or WF from IORT- patients (WF-) (P<0.01). Both WF+ and WF- decreased the cells' migration ability compared to PS (P<0.02) and FBS (P<0.002), although WF+ caused a more significant reduction (P<0.02).

Conclusion: Wound fluid extracted from breast cancer patients who underwent both surgery and IORT increased the growth of breast tumor cells, but decreased their ability to migrate.

Background: Phonocardiogram (PCG) signal provides valuable information for diagnosing heart diseases. However, its applications in quantitative analyses of heart function are limited because the interpretation of this signal is difficult. A key step in quantitative PCG is the identification of the first and second sounds (S1 and S2) in this signal.

Objective: This study aims to develop a hardware-software system for synchronized acquisition of two signals electrocardiogram (ECG) and PCG and to segment the recorded PCG signal via the information provided in the acquired ECG signal.

Material and methods: In this analytical study, we developed a hardware-software system for real-time identification of the first and second heart sounds in the PCG signal. A portable device to capture synchronized ECG and PCG signals was developed. Wavelet de-noising technique was used to remove noise from the signal. Finally, by fusing the information provided by the ECG signal (R-peaks and T-end) into a hidden Markov model (HMM), the first and second heart sounds were identified in the PCG signal.

Results: ECG and PCG signals from 15 healthy adults were acquired and analyzed using the developed system. The average accuracy of the system in correctly detecting the heart sounds was 95.6% for S1 and 93.4% for S2.

Conclusion: The presented system is cost-effective, user-friendly, and accurate in identifying S1 and S2 in PCG signals. Therefore, it might be effective in quantitative PCG and diagnosing heart diseases.

Background: Diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) present the ability to selectively protect functional regions and fiber tracts of the brain when brain tumors are treated with radiotherapy.

Objective: This study aimed to assess whether the incorporation of fMRI and DTI data into the radiation treatment planning process of brain tumors could prevent the neurological parts of the brain from high doses of radiation.

Material and methods: In this investigational theoretical study, the fMRI and DTI data were obtained from eight glioma patients. This patient-specific fMRI and DTI data were attained based on tumor location, the patient's general conditions, and the importance of the functional and fiber tract areas. The functional regions, fiber tracts, anatomical organs at risk, and the tumor were contoured for radiation treatment planning. Finally, the radiation treatment planning with and without fMRI & DTI information was obtained and compared.

Results: The mean dose to the functional areas and the maximum doses were reduced by 25.36% and 18.57% on fMRI & DTI plans compared with the anatomical plans. In addition, 15.59% and 20.84% reductions were achieved in the mean and maximum doses of the fiber tracts, respectively.

Conclusion: This study demonstrated the feasibility of using fMRI and DTI data in radiation treatment planning to maximize radiation protection of the functional cortex and fiber tracts. The mean and maximum doses significantly decreased to neurologically relevant brain regions, resulting in reducing the neuro-cognitive complications and improving the patient's quality of life.

Background: The musculoskeletal complaints of the shoulder are prevalent in people who work with computers for a long time.

Objective: This study aimed to investigate the glenohumeral joint contact forces and kinematics in different keyboards and monitor setups using OpenSim.

Material and methods: Twelve randomly selected healthy males participated in an experimental study. A 3×3 factorial design was used in which three angles were considered for the monitor and three horizontal distances for the keyboard while performing standard tasks. The workstation was adjusted based on ANSI/HFES-100-2007 standard to maintain a comfortable ergonomic posture for controlling confounding variables. Qualisys motion capture system and OpenSim were used.

Results: The maximum mean range of motion (ROM) of both shoulders' flexion and adduction was observed when the keyboard was 15 cm from the edge of the desk, and the monitor angle was 30°. The maximum mean ROM of both shoulders' internal rotation was recorded for the keyboard at the edge of the desk. Peak forces for most right shoulder complex muscles were obtained in two setups. 3D shoulder joint moments were significantly different among nine setups (P-value<0.05). The peak anteroposterior and mediolateral joint contact forces were recorded for the keyboard at 15 cm and the monitor at zero angles (0.751 and 0.780 N/BW, respectively). The peak vertical joint contact force was observed for the keyboard at 15 cm and the monitor at 15° (0.310 N/BW).

Conclusion: The glenohumeral joint contact forces are minimum for the keyboard at 8 cm and the monitor at zero angles.

Background: The patient-specific 3D printed anthropomorphic phantom is used for breast cancer after mastectomy developed by the laboratory of medical physics and biophysics, Department of Physics, Institut Teknologi Sepuluh Nopember, Indonesia. This phantom is applied to simulate and measure the radiation interactions occurring in the human body either using the treatment planning system (TPS) or direct measurement with external beam therapy (EBT) 3 film.

Objective: This study aimed to provide dose measurements in the patient-specific 3D printed anthropomorphic phantom using a TPS and direct measurements using single-beam three-dimensional conformal radiation therapy (3DCRT) technique with electron energy of 6 MeV.

Material and methods: In this experimental study, the patient-specific 3D printed anthropomorphic phantom was used for post-mastectomy radiation therapy. TPS on the phantom was conducted using a 3D-CRT technique with RayPlan 9A software. The single-beam radiation was delivered to the phantom with an angle perpendicular to the breast plane at 337.3° at 6 MeV with a total prescribed dose of 5000 cGy/25 fractions with 200 cGy per fraction.

Results: The doses at planning target volume (PTV) and right lung confirmed a non-significant difference both for TPS and direct measurement with P-values of 0.074 and 0.143, respectively. The dose at the spinal cord showed statistically significant differences with a P-value of 0.002. The result presented a similar skin dose value using either TPS or direct measurement.

Conclusion: The patient-specific 3D printed anthropomorphic phantom for breast cancer after mastectomy on the right side has good potential as an alternative to the evaluation of dosimetry for radiation therapy.

Background: As compared to the flattened photon beam, removing the flattening filter (FF) from the head of a gantry decreases the average energy of the photon beam and increases the dose rate, leading to an impact on the quality of treatment plans.

Objective: This study aimed to compare the quality of intensity-modulated radiation therapy (IMRT) treatment plans for esophageal cancer with and without a flattened filter photon beam.

Material and methods: In this analytical study, 12 patients, who had already been treated with a 6X FF photon beam, were treated based on new IMRT methods using a 6X the flattening filter-free (FFF) photon beam. Both 6X FF IMRT and 6X FFF IMRT plans used identical beam parameters and planning objectives. All plans were evaluated with planning indices and doses for organs at risk (OARs).

Results: Insignificant dose variation was for HI, CI, D_98%, and V_95% between FF and FFF photon beam IMRT plans. FF-based IMRT plan delivered a 15.51 % and 11.27% higher mean dose to both lungs and heart than the FFF plan, respectively. The integral dose (ID) for the heart and lungs was 11.21% and 15.51%, respectively, less in the IMRT plan with an FFF photon beam.

Conclusion: In contrast to the FF photon beam, a filtered photon beam-oriented IMRT plan provides significant OAR sparing without losing the quality of the treatment plan. High monitor units (MUs), low ID, and Beam on Time (BOT) are major highlights of the IMRT plan with FFF beam.

Background: The most common cancer (non-cutaneous) malignancy among men is prostate cancer. Management of prostate cancer, including staging and treatment, playing an important role in decreasing mortality rates. Among all current diagnostic tools, multiparametric MRI (mp-MRI) has shown high potential in localizing and staging prostate cancer. Quantification of mp-MRI helps to decrease the dependency of diagnosis on readers' opinions.

Objective: The aim of this research is to set a method based on quantification of mp-MRI images for discrimination between benign and malignant prostatic lesions with fusion-guided MR imaging/transrectal ultrasonography biopsy as a pathology validation reference.

Material and methods: It is an analytical research that 27 patients underwent the mp-MRI examination, including T1- and T2- weighted and diffusion weighted imaging (DWI). Quantification was done by calculating radiomic features from mp-MRI images. Receiver-operating-characteristic curve was done for each feature to evaluate the discriminatory capacity and linear discriminant analysis (LDA) and leave-one-out cross-validation for feature filtering to estimate the sensitivity, specificity and accuracy of the benign and malignant lesion differentiation process is used.

Results: An accuracy, sensitivity and specificity of 92.6%, 95.2% and 83.3%, respectively, were achieved from a subset of radiomics features obtained from T2-weighted images and apparent diffusion coefficient (ADC) maps for distinguishing benign and malignant prostate lesions.

Conclusion: Quantification of mp-MRI (T2-weighted images and ADC-maps) based on radiomics feature has potential to distinguish benign with appropriate accuracy from malignant prostate lesions. This technique is helpful in preventing needless biopsies in patients and provides an assisted diagnosis for classifications of prostate lesions.

We have previously reported that during future space missions the risk of severe COVID-19 infection will be a cardinal issue that needs careful attention. Our studies show that even with the most reliable pre-mission screening and quarantine strategies, astronauts with a latent (hidden, inactive, or dormant) SARS-CoV-2 infection might be sent to space. Given this consideration, an asymptomatic individual with dormant SARS-CoV-2 infection may successfully pass all the pre-launch medical tests. Then during a space mission such as a journey to Mars or beyond, when the immune system of these astronauts starts to weaken, the dormant infection may progress to a severe infection that possibly affects the chance of the mission's success. The effects of microgravity and the elevated space radiation are two key factors that should be evaluated. Furthermore, the limited size of the spacecraft, the proximity of crew members during flight operations, spacecraft atmospheric composition, limited exercise capability, effects of viral response to space radiation, and uncertainty in the likelihood of the virus to mutate and evolve during a space mission merit additional study.

Background: Functional ankle instability (FAI) is a common injury. Traditional training improved the reported balance impairment and subjective sense of instability in athletes with FAI.

Objective: This study aims to compare the effects of traditional and virtual reality training on a subjective sense of instability and balance in athlete with FAI.

Material and methods: In this single-blinded matched randomized clinical trial design, Fifty-four basketball players were randomly assigned in the virtual reality (n=27) or control (n=27) groups. All athletes performed 12 sessions Wii exercises or traditional training in the virtual reality and the control group, respectively, for three days a week. To assess the subjective-sense of instability and balance, we used Cumberland Ankle Instability Tool (CAIT) and Star Excursion Balance Test (SEBT), respectively. Measures were taken at pre- and post-test and one month after training as a follow-up. The between-group comparisons were done by the analysis of Covariance.

Results: At the pre-test, the CAIT score was 22.37, 22.04 in the control and virtual reality groups, respectively and at the post-test, these scores increased to 26.63, 27.26. The involved limb showed significant differences in posteromedial and posterior directions of the SEBT and CAIT score in the post-test and in the posterior direction and CAIT score in the follow-up. The virtual reality group had better performance than the control group but the effect size is small (cohen's d<0.2).

Conclusion: Based on our results, both training protocols were effective in reducing the subjective-sense of instability and improved balance in athletes with FAI. Moreover, virtual reality training was very attractive for the participants.