Journal of Biomedical Physics & Engineering
Volume:11 Issue: 3, May-Jun 2021

90Y and 177Lu are two well-known radionuclides used in radionuclide therapy to treat neuroendocrine tumors.

This current study aims to evaluate, compare and optimize tumor therapy with 90Y and 177Lu for different volumes of the tumor using the criterion of self-absorbed dose, cross-absorbed dose, absorbed dose profile, absorbed dose uniformity, and dose-volume histogram (DVH) curve using Gate Monte Carlo simulation code.

In our analytical study, Gate Monte Carlo simulation code has been used to model tumors and simulate particle transport. Spherical tumors were modeled from radius 0.5 to 20 mm. Tumors were uniformly designed from water (soft tissue reagent). The full energy spectrum of each radionuclide of 177Lu and 90Y was used in the total volume of tumors with isotropic radiation, homogeneously. Self-absorbed dose, cross-absorbed dose, absorbed dose profile, absorbed dose uniformity, and DVH curve parameters were evaluated.

The absorbed dose for 90Y is higher than 177Lu in all tumors (p-value <5%). The uniformity of the absorbed dose for 177Lu is much greater than 90Y. As the tumor size increases, the DVH graph improves for 90Y.

Based on self-absorbed dose, cross-absorbed dose, absorbed dose uniformity, and DVH diagram, 177Lu and 90Y are appropriate for smaller and larger tumors, respectively. Next, we can evaluate the appropriate cocktail of these radionuclides, in terms of the type of composition, for the treatment of tumors with a specific size.

Computed tomography (CT) is currently known as a versatile imaging tool in the clinic used for almost all types of cancers. The major issue of CT is the health risk, belonging to X-ray radiation exposure. Concerning this, Monte Carlo (MC) simulation is recognized as a key computational technique for estimating and optimizing radiation dose. CT simulation with MCNP/MCNPX MC code has an inherent problem due to the lack of a fan-beam shaped source model. This limitation increases the run time and highly decreases the number of photons passing the body or phantom. Recently, a beta version of MCNP code called MCNP-FBSM (Fan-Beam Source Model) has been developed to pave the simulation way of CT imaging procedure, removing the need of the collimator. This is a new code, which needs to be validated in all aspects.

In this work, we aimed to develop and validate an efficient computational platform based on modified MCNP-FBSM for CT dosimetry purposes.

In this experimental study, a setup is carried out to measure CTDI100 in air and standard dosimetry phantoms. The accuracy of the developed MC CT simulator results has been widely benchmarked through comparison with our measured data, UK’s National Health Service’s reports (known as ImPACT), manufacturer’s data, and other published results.

The minimum and maximum observed mean differences of our simulation results and other above-mentioned data were the 1.5%, and 9.79%, respectively.

The developed FBSM MC computational platform is a beneficial tool for CT dosimetry.

Photothermal therapy (PTT) is a promising method in the field of cancer hyperthermia. In this method, interaction between laser light and photosensitizer material, such as plasmonic nanoparticles, leads into a localized heating. Recent efforts in the area of PTT aim to exploit targeting strategies for preferential accumulation of plasmonic nanoparticles within the tumor.

To investigate the impact of magneto-plasmonic (Au@Fe2O3 ) nanoparticles on temperature profile of CT26 tumor, bearing mice were irradiated by NIR laser.

In this in vivo study, Au@Fe2O3  NPs were injected intraperitoneally to Balb/c mice bearing CT26 colorectal tumor. Immediately after injection, a magnet (magnetic field strength of 0.4 Tesla) was placed on the tumor site for 6 hours in order to concentrate nanoparticles inside the tumor. In the next step, the tumors were exposed with NIR laser source (808 nm; 2 W/cm2; 5 min).

Tumor temperature without magnetic targeting increased ~7 ± 0.9 °C after NIR irradiation, whereas the tumors in magnetic targeted group experienced a temperature rise of ~12 ± 1.4 °C.

It is concluded that Au@Fe2O3 nanoparticle is a good candidate for therapeutic nanostructure in cancer photothermal therapy.

Euronext Paris Advanced Orthopedic Solutions (EOS) system is a new radiography system, capable of obtaining two-dimensional and three-dimensional images from bony structures in the body.

The aim of this study is to estimate equivalent dose and the risk of exposure induced cancer death (REID) in different organs of body due to EOS imaging system.

In this experimental study, totally 120 patients were evaluated for various imaging techniques of lower limb, full spine and whole body. Equivalent dose and REID for colon, liver, lung, stomach, breast, bladder, ovary, blood cells (leukemia) and other organs were calculated using PCXMC software (version 2.0.1.2) based on Monte Carlo simulation of X-ray and human phantoms. The data on imaging technique, including age, sex, kVp, dose area product (DAP), mA, focal to detector distance were introduced as the input of PCXMC.

The maximum equivalent dose (mSv) due to EOS imaging system, was estimated for the bladder 0.240±0.066 for the full body technique and 0.240±0.093 for the lower limb technique, respectively, in both males and females. The maximum organ REID (incidence per million) due to EOS imaging system was estimated for lungs as 2.59±1.0 and 2.53±0.9, for the full body technique in both males and females, respectively.

Generally, the equivalent dose and REID by EOS imaging system in different organs of body is low due to the low radiation dose received by the body in different techniques and views.

Despite existing some research on the effects of professional cycling on cyclist’s spinal curvature angles, no research is available concentrating on possible differences in various types of professional cycling. Road (outdoor) and speed (indoor) cyclists have different anthropometric and predominant postures during cycling. The current study aims to investigate if cyclists with different types of cycling may have dissimilar spinal curvature adaptations.

Forty-eight male subjects, including 16 elite road cyclists, 16 elite sprint cyclists and 16 non-athletes as the control group were recruited in this non-experimental study.

In this cross-sectional study, a spinal mouse was used to measure the thoracic and lumbar curvature angles in standing position.

The mean values of thoracic kyphosis and lumbar lordosis angles were found as follows: 48.3±7.2º & -20.3±7.2º for elite road cyclists; 46.6±8.1º & -22.5±7.7º for elite sprint cyclists; and 37.5±4.1º & -19±6.3º for the control group. The results confirmed that both the road and sprint cyclists showed significantly more hyper-kyphosis posture in their thoracic region when compared to the control group (p <0.05).

All road cyclists showed no significantly higher degrees of thoracic angle relative to the sprint cyclists (p>0.05). However, all the cyclists and the control groups showed a normal range of lumbar lordosis angle. As a conclusion, the results of this study confirmed that an elite cyclist may predispose these subjects to the risk of hyper-kyphotic posture. The road cycling may result in more hyper-kyphosis due to the longer time, spent in flexed position.

Beam hardening and scattering artifacts from high-density objects such as dental implants adversely affect the image quality and subsequently the detection of fenestration or dehiscence around dental implants.

This study aimed to assess the efficacy of metal artifact reduction (MAR) algorithm of two cone-beam computed tomography (CBCT) systems for detection of peri-implant fenestration and dehiscence.

In this experimental study, thirty-six titanium implants were placed in bone blocks of bovine ribs. Fenestration and dehiscence were created in the buccal bone around implants. CBCT images were obtained using Cranex 3D and ProMax 3D CBCT systems with and without MAR algorithm. Two experienced radiologists observed the images. Data were analyzed using SPSS software. The Kappa coefficient of agreement, the area under the receiver operating characteristic (ROC) curve, sensitivity, specificity, and accuracy of different imaging modalities were calculated and analyzed.

In both CBCT systems, the use of MAR algorithm decreased the area under the ROC curve and subsequently the diagnostic accuracy for the detection of fenestration and dehiscence. The sensitivity, specificity and accuracy of both CBCT systems were higher in absence of the MAR algorithm. The specificity of ProMax 3D for detection of fenestration was equal with/without the MAR algorithm.

Although CBCT is suitable for detection of peri-implant defects, the application of the MAR algorithm does not enhance the detection of peri-implant fenestration and dehiscence.

The paper points out the importance of quantifying the extent and nature of organ and tissue injury within the assessment of severity of damage to health caused by effect of blunt or combined force. This study aims to determine the value of mechanical violence that caused the injury using the Fortis system based on the detected range of injured soft tissue and the localization of the sites affected by said violence. In this experimental study the authors carried out measurements and calculations in 10 pedestrians, who died of polytrauma in an accident. The morphometric Ellipse v.2.0.7.1.software was used for the purpose (Vidito Kosice, Slovak Republic). The internal organ injuries were successfully evaluated in a planographic manner on serial sections with the following calculation of total extent of tissue damage (TETD). It turned out that if TETD is more than 40%, it will be possible to evaluate an injury as severe or life-threatening. The above classification and localization of pedestrian injuries facilitate calculations in simulation programs to determine how the movement of a pedestrian´s body during and after the collision occurred based on the unrepeatability of movement parameters; besides, contacts with a vehicle help determine the input data to calculate the collision. Based on the submitted case reports and performed measurements and calculations, the presented method of the extent classification of soft tissue damage is evaluated to be useful to standardize the injury parameters and assess polytrauma as a result of disproportionate force.

Interactions of many key proteins or genes in signalling pathway have been studied qualitatively in the literature, but only little quantitative information is available.

Although much has been done to clarify the biochemistry of transcriptional dynamics in signalling pathway, it remains difficult to find out and predict quantitative responses. The aim of this study is to construct a computational model of epidermal growth factor receptor (EGFR) signalling pathway as one of hallmarks of cancer so as to predict quantitative responses.

In this analytical study, we presented a computational model to investigate EGFR signalling pathway. Interaction of Arsenic trioxide (ATO) with EGFR signalling pathway factors has been elicited by systematic search in data bases, as ATO is one of the mysterious chemotherapy agents that control EGFR expression in cancer. ATO has dichotomous manner in vivo, dependent on its concentration. According to fuzzy rules based upon qualitative knowledge and Petri Net, we can construct a quantitative model to describe ATO mechanism in EGFR signalling pathway.

By Fuzzy Logic models that have the potential to trade with the loss of quantitative information on how different species interact, along with Petri net quantitatively describe the dynamics of EGFR signalling pathway. By this model the dynamic of different factors in EGFR signalling pathway is achieved.

The use of Fuzzy Logic and PNs in biological network modelling causes a deeper understanding and comprehensive analysis of the biological networks.

Axial load on thoracolumbar junction, both mechanical and anatomical transitional zone, causes the compression and flexion of the spine, and consequently thoracolumbar burst fractures.

This study aimed to investigate the effect and prognostic factors associated with the postural and instrumented reduction on the restoration of vertebral height and kyphosis angle in thoracolumbar burst fractures.

This retrospective cohort study was conducted on 41 patients with A3, A4, and B type thoracolumbar burst fractures, subjected to postural and instrumented reduction for the restoration of vertebral height and kyphosis angle. The magnitude and correction of kyphotic deformity and percentage of vertebral body collapse were measured before and after postural reduction, and after instrumental insertion to find if they were affected by fracture type and level, time-to-surgery, and use of pedicular screws at the fractured level.

Postural and instrumental reduction significantly improved both the kyphosis angle and the percentage of vertebral body height, regardless of AO types (p.value

AO type A3, and A4, time to surgery before 4 days, and fracture level at L2 were favorable prognostic factors to better restoration of kyphosis angle using both postural and instrumented reduction.

Acute graft-versus-host disease (aGvHD) is a complex and often multisystem disease that causes morbidity and mortality in 35% of patients receiving allogeneic hematopoietic stem cell transplantation (AHSCT).

This study aimed to implement a Clinical Decision Support System (CDSS) for predicting aGvHD following AHSCT on the transplantation day.

In this developmental study, the data of 182 patients with 31 attributes, which referred to Taleghani Hospital Tehran, Iran during 2009–2017, were analyzed by machine learning (ML) algorithms which included XGBClassifier, HistGradientBoostingClassifier, AdaBoostClassifier, and RandomForestClassifier. The criteria measurement used to evaluate these algorithms included accuracy, sensitivity, and specificity. Using the machine learning developed model, a CDSS was implemented. The performance of the CDSS was evaluated by Cohen’s Kappa coefficient.

Of the 31 included variables, albumin, uric acid, C-reactive protein, donor age, platelet, lactate Dehydrogenase, and Hemoglobin were identified as the most important predictors. The two algorithms XGBClassifier and HistGradientBoostingClassifier with an average accuracy of 90.70%, sensitivity of 92.5%, and specificity of 89.13% were selected as the most appropriate ML models for predicting aGvHD. The agreement between CDSS prediction and patient outcome was 92%.

ML methods can reliably predict the likelihood of aGvHD at the time of transplantation. These methods can help us to limit the number of risk factors to those that have significant effects on the outcome. However, their performance is heavily dependent on selecting the appropriate methods and algorithms. The next generations of CDSS may use more and more machine learning approaches.

Deep neural networks have been widely used in detection of P300 signal in Brain Machine Interface (BMI) systems which are rely on Event-Related Potentials (ERPs) (i.e. P300 signals). Such networks have high curvature variation in their error surface hampering their favorable performance. Therefore, the variations in curvature of the error surface must be minimized to improve the performance of these networks in detecting P300 signals.

The aim of this paper is to introduce a method for minimizing the curvature of the error surface during training Convolutional Neural Network (CNN). The curvature variation of the error surface is highly dependent on model parameters of deep neural network; therefore, we try to minimize this curvature by optimizing the model parameters.

In this experimental study an attempt is made to tune the CNN parameters affecting the curvature of its error surface in order to obtain the best possible learning. For achieving this goal, Genetic Algorithm is utilized to optimize the above parameters in order to minimize the curvature variations.

The performance of the proposed algorithm was evaluated on EPFL dataset. The obtained results demonstrated that the proposed method detected the P300 signals with maximally 98.91% classification accuracy and 98.54% True Positive Ratio (TPR).

The obtained results showed that using genetic algorithm for minimizing curvature of the error surface in CNN increased its accuracy in parallel with decreasing the variance of the results. Consequently, it may be concluded that the proposed method has considerable potential to be used as P300 detection module in BMI applications.

Controlling pelvic excursions is the focus of stabilization exercises such as legs loading tasks in rehabilitation of non-specific chronic low back pain (NSCLBP) patients. Progression of these exercises is based on the ability to perform tasks with minimal sagittal pelvic excursions. In spite of emphasis on minimizing pelvic motions, no previous studies have investigated kinematic analysis of the pelvic excursions during leg loading exercises in NSCLBP patients. This study aims to investigate the sagittal pelvis excursion during performing asymmetric leg loading tasks in individuals with and without NSCLBP. In this cross-sectional study, kinematic data were collected from 15 NSCLBP patients and 15 asymptomatic participants by a motion analysis system during right and left leg loading tasks with 2 levels of difficulty. Pelvis segments were modeled using Visual3D motion analysis software. Maximum pelvic excursion in the sagittal plane was calculated during each task. Mixed model analysis of variances (group, task difficulty level, side) was performed for statistical analysis. The maximum sagittal pelvic excursion values of all tasks in NSCLBP were smaller than those in the control group; however, no significant main effects and interactions were found between two groups. These results suggest that NSCLBP patients completed loading tasks without differences in sagittal pelvic excursions as compared to controls. Assessment of NSCLBP patients only based on pelvic angular excursion may not be sufficient for clinical decision making. Furthermore, asymptomatic individuals may need to practice for controlling pelvic excursion during leg loading exercises similar to the CLBP patients.

The heart is the major dose-limiting organ for radiotherapy of malignant tumor in the mediastanal region. This study aims to investigate the radio protective effects of Hesperidin (HES) as a natural flavonoid after localized irradiation of the rat’s mediastinum region. In this experimental study, we divided sixty male rats into 4 groups (n=15). First group: Sham which received PBS; second group: Hesperidin only (100 mg/kg/day orally) for one week; third group: Radiation that received single dose of 20 Gy gamma radiation using Co-60 unit and the forth group: Radiation+HES that underwent the same dose of radiation and received HES for 7 days prior irradiation. Each group was divided in two branches. Early sampling from subgroup one was done 4-6 hours after irradiation to determine troponin-1 level changes. Rats of second subgroups were killed 56 days after irradiation for histopathological evidence. In radiation group, troponin -1 serum level had a significant increase in comparison with sham group (p <0.05). Histopathological evaluation of second subgroup showed there was a significant difference between sham and radiation group in some parameters. Inflammation (p=0.008), pericardial effusion (P=0.001), and vascular plaque (P=0.001) had an increase in the irradiation group. Oral administration of hesperidin significantly decreased all the above factors when was compared with irradiation group (P>0.016). Oral administration of Hesperidine for seven days prior radiotherapy may decrease troponin-1 and cardiac injury due to radiation.

Recent studies reported the significant expansion using 8-Hydroxy-2-Deoxyguanosine (8-OHdG) as a biomarker of oxidative Deoxyribonucleic Acid (DNA) damage among human populations exposed to medical ionizing radiation, but a generalized overview about this topic has not been conducted yet.

This scoping review of published literature examined recent trends in utilizing 8-OHdG biomarker to measure oxidative DNA damage induced by medical ionizing radiation and possible factors that may influence the 8-OHdG level.

Literature search was conducted in PubMed, Scopus and ProQuest databases for publications from 1984 to 2/12/2020. Included articles were: cohort studies, case-control studies, and cross–sectional studies, randomized and nonrandomized controlled trials. Excluded articles were: editorials, letters, personal opinions, newspaper articles, study plans, protocols, qualitative studies, case reports and series, in-vivo and vitro studies, animal research studies, reviews and meta-analyses.

According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we screened 141 articles, and 10 eligible studies met our inclusion criteria. All studies measured 8-OHdG as an oxidative DNA damage biomarker. The study results were contradictory concerning the relationship between the radiation dose and 8-OhdG level. 8-OHdG was mostly measured by enzyme-linked immunosorbent assay (ELISA) using urine samples. Sample size varied between (n=25-230) and included patients who underwent medical radiation procedures or workers exposed to ionizing radiation during their jobs.

This scoping review findings showed 8-OHdG can be used as a promising biomarker to detect oxidative damage, resulting from medical ionizing radiation exposure despite external factors that may influence 8-OHdG levels.

The COVID-19 global pandemic has drastically affected the health care facility worldwide, posing unprecedented challenges in front of the caregivers. All hospitals need adopt measures to protect patients and health professionals and to safely triage patients (according to country/regional directives) for identifying those infected with coronavirus. As very few guidelines are available for care of cancer patients during COVID times, institutes have had to make their own strategies, based on their own expertise keeping in mind local directives and their effect on available resources and routine processes to offer best possible care. In this article, we have discussed in-house protocols for modification and prioritization of radical and palliative multimodality treatment of cancer patients along with our infection control measures in accordance with national and local guidelines during COVID emergency to stay safe and health. Also, the current study aims to modify cancer treatment and care during the COVID-19 pandemic adhering and fulfilling all protective measures.

The inevitable use of medical imaging examinations and lack of a suitable alternative lead to the need to control and minimize the amount of radiation from such artificial medical sources. To assess the relation between exposure parameters and lifetime of radiology devices, quality control tests were carried out on 13 radiology devices in 11 general hospitals. In this study, a barracuda dosimeter, SE-43137 Sweden, was calibrated to measure and record the quantities of kVp, mAs and exposure parameters. In all the devices using applying the minimum and maximum values of kVp, the minimum and maximum values of the internal resistances were calculated. The lowest mR/mA for the device C was observed at a flow rate of 200 mA (equal to 2,425), while the highest value was for the device A (2) at a current intensity of 200 mA (equal to 14.625). By increasing the age of the device, the output of the device is reduced. Therefore, to compensate for this decrease in the output, higher exposure conditions are usually applied to the device, which can greatly increase the damage to the device.