Frontiers in Biomedical Technologies

Filters Effect on Image Quality of 177Lu-DOTATATE SPECT Images for Neuro-Endocrine Tumors Scanning

2025-01-31T18:46:34+00:00

Purpose: The quality of the image in SPECT scans depends on the imaging parameters which are determined experimentally in the field of nuclear medicine. Designing a dedicated scanning parameter for ¹⁷⁷Lu-DOTATATE SPECT images is required to optimize reconstruction. Therefore, this study aims to evaluate the effect of different filters on image quality for bone SPECT scanning using ¹⁷⁷Lu-DOTATATE.

Materials and Methods: The filtered back-projection reconstruction method was used in neuro-endocrine tumor scanning using ¹⁷⁷Lu-DOTATATE. Three hours after injection of ¹⁷⁷Lu-DOTATATE, SPECT scans from ¹⁷⁷Lu-DOTATATE for 30 patients were acquired using a dual-head EvoExel detector system. Seven parameters were considered, including the contrast/noise ratio, injection activity, uptake duration, acquisition time per injection, frame time, measuring time, and type of filters.

Results: In all cases, the application of different filters increased Contrast to Noise Ratio (CNR) (9.1%, 1.8%, 10.9%, 61.8%, 23.6%, 29.1%, and 58.2% for Wiener, Butterworth, Parzen, Metz, Ramp, Shepp-Logan, and Hamming filters, respectively). The percentage of increase in Signal-to-Noise Ratio (SNR) was 3.3%, 1.7%, -24%, 21.7%, 9.8%, 11.9%, and 20.6%.

Conclusion: Based on the quantitative analysis of the results, the application of the Metz filter (power 2) and Hamming filter (with 0.27, 0.47, and 0.67 cut-off frequencies) on SPECT scans of neuro-endocrine tumors is recommended because of their capacity to provide high-quality images.

Assessment of Staff’s Knowledge, Attitude, and Practice on Radiation Protection Measures in Mazandaran Province, Iran

2025-01-31T18:46:32+00:00

Purpose: Ionizing radiation in medical imaging is one of the dominant diagnostic tools, and also correct knowledge of radiation protection affects staff safety behaviors during examinations. This study highlights the radiation protection Knowledge, Attitude, and Practice (KAP) amongst a large number of hospitals and medical centers in Mazandaran province of Iran.

Materials and Methods: In order to assess the level of radiation protection KAP, a validated questionnaire was given to all MAZUMS-affiliated hospitals and clinics. Four hundred fifty-five staff members participated by responding to an original questionnaire. The sample consisted of nurses, radiographers, and medical doctors of various specialties involved daily in surgical procedures where ionizing radiation is required. The survey was conducted from April 2021 to January 2022, and the response rate was 72.3%.

Results: There were statistically significant differences in the level of staff KAP radiation protection with gender (p < 0.05), practicing age KAP level and radiation protection (p < 0.05), and there is no significant relationship between educational age and staff KAP level of radiation protection (p > 0.05).

Conclusion: Our findings revealed that the level of overall radiation protection KAP level of workers regarding radiation protection safety was satisfactory but in some parameters it was insufficient. This could be due to a lack of consistent training and proper protection against ionizing radiation.

Frontal Pole, Cingulate Gyrus, and Precuneus Cortex Represent the Confidence Level in the Prediction of others' Risky Decision-Making

2025-01-31T18:46:30+00:00

Purpose: Reporting confidence after a decision-making task is widely used in the studies of metacognition. A cognitive factor is usually defined as “thinking about thinking.” When people predict others’ behavior in risky situations, they consider various factors affecting others’ choices; at that point, they can determine how confident they are about their predictions about the others' decision.

Materials and Methods: This study investigates human neural activities in different confidence levels when participants predict others’ financial choices in a risky decision-making task. For this aim, functional Magnetic Resonance Imaging (fMRI) combined with behavioral tasks is used to demonstrate the neural representation of human confidence level about others’ possible choices. We scanned 21 healthy and normal participants in two separate sessions each containing three runs.

Results: The results indicate that the Frontal Pole Cortex (FPC), cingulate gyrus, and precuneus cortex activities are correlated with the confidence of people in their predictions (P < 0.0005; cluster size, k > 75). Using behavioral data, we found that when participants answer correctly, their confidence level as a metacognition factor increases simultaneously and vice versa.

Conclusion: These key findings suggest that the brain's activities can represent subjects’ confidence level in predicting risky behaviors and show how metacognition in the theory of mind for prediction of others’ choices is represented in the brain’s activity.

Evaluation of Patients’ Received Doses in Chest CT Scan Protocols: A Retrospective Study

2025-01-31T18:46:28+00:00

Purpose: This study aims to investigate and compare the doses received by Corona Virus Disease (Covid-19) patients on Computed Tomography (CT) scans by changing the scan parameters to diagnose the disease and evaluate its course and effects.

Materials and Methods: The total number of patients was 8290, with 4070 requesting a CT scan of the lungs. In 3512 cases, the purpose of the examination was to verify Covid-19. The remaining 558 scans were for other diseases. Two CT protocols were used for lung imaging: A low-dose protocol (kV = 120 kVp and mAs = 80ms) to screen for Covid-19 and a Smart protocol (kV = 120 kVp and mAs = Smart) for other diseases. Each image was assigned a score from 1 to 5. The score reflects the quality of the image and Covid-19-related features such as Ground Glass Opacities (GGO), crazy paving, consolidation, Nodular Infiltrates (NI), Broncho Vascular Thickening (BVT), and Pleural Effusion (PE).

Results: In the low-dose protocol, the effective dose received by patients varied between 1.98 and 2.66 ± 0.1 milli Sievert (mSv) according to the different Dose-Length Product (DLP) values. The effective dose varies between 2.7 and 8.44 mSv for the Smart protocol. The maximum Size-Specific Dose Estimate (SSDE) was 11.97 ± 0.2 and 21.58 ± 0.9 milli Gray (mGy) for each protocol, respectively. The maximum carcinogenicity was 1.09 × 10⁻⁴ and 3.05 × 10−4, respectively. Radiologists gave an overall acceptance rate of 4.9 ± 0.1 and 4.8 ± 0.2 out of a possible 5-point for images with low-dose and smart protocols, respectively.

Conclusion: Decreasing the value of milli Ampere-seconds (mAs) decreases the effective dose, the size-specific dose estimate, and the carcinogenicity of radiation in patients requesting scans of the lungs CT. Images lose quality but are still good enough to determine the progression and impact of Covid-19.

Internal Dosimetry in Patients Undergoing Peptide Receptor Radionuclide Therapy (PRRT) with 177Lu-[DOTA0-Tyr3 octerotate: A Single-Center Experience

2025-01-31T18:46:26+00:00

Purpose: Peptide Receptor Radionuclide Therapy (PRRT) with ¹⁷⁷Lu-DOTATATE (¹⁷⁷ Lu DOTA-TATE therapy is a form of PRRT which targets Somatostatin Receptors (SSR). It is a form of targeted drug delivery, which is applicable to treat neuroendocrine tumors. PRRT applications are continuously expanding in most departments of nuclear medicine in Iran, but the best of all, no one has studied the mean doses of organs of the patients. This research aims to specify the absorbed dose to patients for the treatment of neuroendocrine tumors using imaging with ¹⁷⁷Lu-[DOTA0-Tyr3] octerotate.

Materials and Methods: Whole body planar scintigraphy images were collected for 10 patients, which are used as the basis for the personalized patient dosimetry calculations. The patients had a mean age of 53.5 ± 12 years (ranging from 36 to 70 years) and imaging data were collected at roughly 0 to 2 hours, 4 to 6 hours, 18 to 24 hours, and 36 to 48 hours after the injection of 6401± 628.4 MBq (range of 5500 MBq-7400 MBq) of ¹⁷⁷Lu-[DOTA0-Tyr³] octerotate. Models of time-activity were established for different organs. Finally, using absorbed dose formulation and IDIAC-Dosage software, the mean absorbed dose in the organs was determined.

Results: Mean calculated dose in the kidney and liver were obtained as 0.30-0.82 mGy/ MBq, and 1.05-2.11 mGy/MBq, respectively.

Conclusion: Based on the results, PRRT therapy is a safe method for the treatment of castration-resistant neuroendocrine cancer patients in terms of patient dose. Large inter-individual differences in organ dose were discovered, highlighting the importance of patient-specific dosimetry and treatment planning in the treatment with ¹⁷⁷Lu-DOTATATE.

Multiclass Supervised Learning Approach for SAR-COV2 Severity and Scope Prediction: SC2SSP Framework

2025-01-31T18:46:24+00:00

Purpose: Identifying high-risk areas for the virus or the potential for the technique to be applied to this infectious disease might be difficult. The existing tools being used for predicting viruses exhibit various limitations. The severe pneumonia caused by the rapidly spreading coronavirus disease (COVID-19) is predicted to have a significant negative impact on the healthcare sector. Accurate treatment requires an urgent need for early diagnosis, which reduces pressure on the healthcare system. Computed Tomography (CT) scan and Chest X-Ray (CXR) are some of the standard image diagnoses. Although a CT scan is the most common method for diagnosis, CXR is the most frequently utilized since it is more accessible, quicker, and less expensive.

Materials and Methods: In this manuscript, the proposed model SC2SSP is a multiclass supervised learning technique that aims to predict the scope and severity of the SAR-COV2 virus using data on confirmed cases and deaths. The model may also utilize preprocessing techniques which are Gaussian smoothing for handling imbalanced data, such as oversampling or under sampling, as well as feature extraction methods such as Local Binary Pattern to identify the most relevant input features for the prediction task. Additionally, a classifier such as XGBoost can also be used to further improve the model's performance. This makes the model more robust and accurate in predicting the scope and severity of the SAR-COV2 virus.

Results: The model utilizes the Exact Greedy Algorithm to classify the spread and impact of the virus in different regions. The performance metrics like accuracy, precision, fscore and sensitivity are analyzing the proposed method performance. The proposed SC2SSP approach attains 3.101% and 7.12% higher accuracy; 24.13% and 13.04% higher precision compared with existing methods, like the Detection of COVID-19 from Chest X-ray Images Using Convolutional Neural Networks (Resnet50), Deep learning for automated recognition of covid-19 from chest X-ray images (VGGNet), respectively.

Conclusion: The conclusion and potential future healthcare planning follow the exploration of evidence-based approaches and modalities in the scope and forecast.

Characterizing the Flow and Interaction of Microbubbles in a 2D Capillary Network for Targeted Drug Delivery: A Simulation Study

2025-01-31T18:46:22+00:00

Purpose: Microbubble ultrasound contrast agents inside the bloodstream enhance the ultrasound signals of the vascular bed. In addition, microbubbles can be used for treatment. The present study assesses how air bubbles flow in a microchannel 2D capillary network. The evaluated network mimics part of a capillary system by comprising multiple bifurcations.

Materials and Methods: We designed the capillary network based on the tree pattern employed in quantitative studies per Murray’s minimum work rule and the cardiovascular network to simulate the hemodynamics of the vessels. The maximum width of the main channels in the capillary network is 1085 µm. The capillary network designed by AutoCAD software was transferred to Comsol software. We also ran fluid-structure interaction simulations in a microchannel capillary network, assuming that capillary walls were incompressible and isotropic, physiological boundary conditions were met, and non-Newtonian blood behavior occurred. After these simulations, we investigated Microbubbles’ (MBs’) capacity for targeted drug delivery through the capillary network. Specifically, we distributed four particles with 1 to 5 µm diameters and assessed the resultant performance.

Results: The greatest capillary network wall displacement is 0.225 µm. Meanwhile, the maximum velocity was 5.59 mm/s, and the minimum and maximum pressure values were 303.13 Pa and 0.42 Pa. Finally, the MB-MB interaction force exceeded the Brownian and gravitational forces. Therefore, it can be concluded that the MB-MB interaction force is crucial for MB-based targeted drug delivery. The kinetic energy of microbubbles increases while passing through the capillary bed. By increasing the amount of kinetic energy of microbubbles, the probability of adhesion to the capillary wall decreases. As the diameter of microbubbles increases, their energy increases.

Conclusion: The kinetic energy of microbubbles in the same conditions is the highest value related to Sonovue and then related to Optison, Micromarker, and Definity, respectively. The highest percentage of passing through the capillary network belongs to the Sonovue with a diameter of 2.5 µm and the lowest percentage of passing through the capillary network belongs to the Definity with a diameter of 1.1 µm.

A Feasibility Study on Nano-Particle Properties for Signal Generation at NaI(Tl) Scintillation Detectors

2025-01-31T18:46:20+00:00

Purpose: Scintillators have become a prevalent method for detecting ionizing radiation due to their ability to produce optical photons that serve as the basis for the final signal representing the physical properties of the incident beam. This signal is generated using interface hardware such as photon multipliers or photodiodes, in conjunction with the scintillator body. A feasibility study was undertaken to investigate a new interface and detector body based on nano-technology and nano-particle materials, which could potentially eliminate the need for the current photon multipliers.

Materials and Methods: The study involved simulating various incidence beams to determine the wavelengths and intensities of light photons emitted from a NaI(Tl) scintillation detector. The absorption and scatter phenomena of light photons were then modeled using a discrete dipole approximation code, with silver being proposed as the nano-particle material. The silver nano-sphere was implemented as a cubic array with numerous point dipoles distributed on a cubic lattice. An experimental verification was also performed, using Silver Nanoparticle material in powder form, irradiated by 420 nm visible photons.

Results: Based on the numerical results, it is feasible to use nano-material properties as a replacement for current light multipliers. The experimental results confirmed variations in the frequency of the function generator, which was chosen as a typical signal.

Conclusion: However, concerns may arise regarding the implementation of the necessary hardware to retrieve the produced signal as output from the nano-material component, to represent ionizing beam characteristics.

Ultrasonographic Assessment of Intima-Media Thickness (IMT), as a Surrogate of Future Atherosclerosis and Cardiac Diseases in Patients with Hashimoto’s Thyroiditis and Concomitant Celiac Disease: A Case-Control Study

2025-01-31T18:46:18+00:00

Purpose: Intima-Media Thickness (IMT), which is frequently evaluated by B-mode ultrasound study, has been proved to be a reliable surrogate marker for atherosclerosis progression and a predictor of upcoming cardiovascular risks. Sonographic changes of intima-media thickness of carotid artery in Hashimoto’s thyroiditis and Celiac disease have been investigated separately. In this study we aimed to evaluate the changes in sonographic appearance of the carotid artery and its mural thickness in patients with Hashimoto’s thyroiditis and concomitant Celiac disease, as a surrogate marker of atherosclerosis and a predictor of cardiovascular diseases.

Materials and Methods: A total of 191 patients including 89 patients with only Hashimoto’s thyroiditis, 11 patients with Hashimoto’s thyroiditis and concomitant Celiac disease, and 91 healthy control subjects underwent ultrasound evaluation of intima-media thickness of carotid artery. High resolution B-mode images with a multi-frequency linear probe, were utilized for assessing the IMT.

Results: IMT in the Hashimoto with celiac disease group was 0.72 ± 0.11 and was 0.69 ± 0.09 in the Hashimoto without celiac disease group and was 0.63 ± 0.10 in the control group. IMT showed significant difference between the three groups and was higher in the Hashimoto patients compared to the control group (P-Value = 0.039 and 0.028). Moreover, IMT was marginally higher in the Hashimoto patients with celiac disease compared to the Hashimoto patients without celiac disease (P-Value = 0.046).

Conclusion: Patients with Hashimoto’s thyroiditis suffering from concomitant Celiac disease, showed a more increased IMT values compared to other subjects. This can indicate the potential importance and predictive value of ultrasonic IMT evaluation in Celiac disease and Hashimoto’s thyroiditis as a marker of atherosclerosis progression as well as future risk of cardiovascular insults.

Investigation of the Physical Properties of Different Ion Species at Hadron Therapy; A Comprehensive Study

2025-01-31T18:46:16+00:00

Purpose: Recently, using hadrons as a therapeutic beam has been highly advised for radiation treatment of mainly deep-seated tumors due to the desired conforming of three-dimensional dose conformation onto tumor volume. This refers to the physical properties of commonly available hadrons versus photons and electrons in colliding with patient body atoms which is our main challenge in this study, in a comparative fashion.

Materials and Methods: In this work, protons Caron- and Oxygen-Ions are considered as hadron beams while irradiating a given tumor located at soft tissue equivalent phantom to mimic the patient body using FLUKA simulation code. The high-impact properties of available beams implemented at hadron therapy facilities are investigated quantitatively, during the simulation process while no study has been done formerly.

Results: Depth dose profiles of hadrons, linear energy transfer, beams lateral divergence, spread out Bragg peak, produced neutrons and positron emitter as radioisotopes produced due to colliding hadrons with the nucleus of the atoms are measured, numerically. The latter case include C¹⁰, C¹¹, N¹³, and O¹⁵ in soft tissue which are highly important for proton range verification inside the patient body using positron emission tomography.

Conclusion: The physical properties of different therapeutic ion species were compared comprehensively. Among hadrons, linear energy transfer of Carbon- and Oxygen ions is superior versus proton due to their high atomic numbers that reduce treatment sessions remarkably. Furthermore, in proton therapy, the main source of produced neutrons are passive or active modulation devices located in front of the therapeutic beam. Among produced positron emitters, C¹¹ and O¹⁵ are remarkable for providing functional images to assess the hadron range inside the patient body.

An Analysis of the Rate and Reasons for Rejected Radiographs in Emergency and Non-emergency Radiology Departments in Yasuj, Iran

2025-01-31T18:46:15+00:00

Purpose: Utilizing imaging to improve physicians' diagnostic accuracy is one of the primary priorities of radiology departments. When the image is of poor quality, it is likely to be rejected, and its repetition will expose patients and staff to unnecessary ionizing radiation. Given the significant nature of this issue, the current study aimed to evaluate the rate and reasons for radiograph rejections in emergency (public practice) and non-emergency (private practice) radiology departments of Yasuj, Iran.

Materials and Methods: This cross-sectional study was carried out over 14 days in Yasuj, Iran, in the accident and emergency (round-the-clock) and non-emergency (day) medical imaging departments. In terms of quality, a total of 7,006 images were classified into the following three grades; A (Good), B (Fair), and C (rejected). The grade C radiographs were categorized into 9 classes according to the reasons for rejection.

Results: During this study, 7,006 radiographs were examined, of which 6,458 (92.2%) were categorized as grade A. Additionally, 401 radiographs (5.7%) were categorized as grade B, and 147 radiographs (2.1%) were considered to be grade C, which means that they were rejected. Out of the rejected radiographs, 69 (1.9%) were from emergency departments, while 78 (2.3%) were from non-emergency radiology departments. The most common reasons for the rejection of radiographs were the patient's incorrect positioning in 45 cases (30.6%) and the patient's motion in 43 cases (29.3%).

Conclusion: In comparison to previous research, the current study's percentage of rejected images was deemed acceptable. Radiologists are advised to frequently assess the reason and rate for rejecting radiographs to enhance the effectiveness of their radiology unit.

Diagnostic Accuracy of Mammography, Ultrasound, and Fine-Needle Aspiration in Detecting Breast Cancer in Patients with Painful Breast Masses: A Medical Record-Base Study

2025-01-31T18:46:13+00:00

Purpose: The objective of our investigation was to conduct a comparative analysis of the precision levels of fine-needle aspiration, ultrasonography, and mammography with regard to detecting the presence of breast cancer. The ultimate goal was to determine the most effective diagnostic methodology based on the patient's age and the particular attributes of the mass in question.

Materials and Methods: This cross-sectional study examined 150 patients who presented breast pain within the last six months. Out of the initial cohort, 66 participants diagnosed with breast cancer were included in the study, presenting an age range of 35 to 98 years and a mean age of 53.72 ± 18.26 years. Among them, six were single and 60 were married. The results of diagnostic tests were compared with pathological findings and the final diagnosis was determined using the chi-square test.

Results: The findings suggested that 10% of masses were hyper-echoic and 90% hypo-echoic on sonography. Sonography showed that 53.3% of the masses were cystic and 46.7% solid. Mammographic results revealed calcifications in 24.2% of masses, with 63.6% showing no calcifications. Mammography, with a sensitivity of 87.8%, was the only modality that could detect calcifications.

Conclusion: Our study suggests that combining diagnostic methods enhances breast lesion detection compared to using a single method. This is crucial in early cancer stages when accurate, timely diagnosis is key. This approach improves early breast cancer detection, leading to better patient outcomes.

The Effect of Various Parameters on Measuring Alpha and Beta Particles from Soil Sample; An Environmental Dosimetry

2025-01-31T18:46:09+00:00

Purpose: The measurement of natural radioactive decay in environmental samples such as soil has received increasing importance in recent years. Proportional counters in the form of large-area planar detectors are widely used for the initial screening of radioactivity in environmental samples. In this study, the affecting factors in the alpha and beta particles emitted from natural radioactive soil sample was simulated using the Monte Carlo FLUKA code.

Materials and Methods: These factors include the thickness of the sample, source-detector air gap, Mylar thickness, and gas detector density. Simulations were performed for alpha particles in 4.8 MeV and in the conventional range for the investigation of radioactive elements inside the soil sample.

Results: The final analyzed results show that the maximum number of primary particles can be measured up to 5 and 100 µm of soil sample thickness for alpha and beta particles, respectively. The maximum counting efficiencies for alpha and beta particles are 23% and 42%, respectively for our simulated sample.

Conclusion: For alpha particles, gas detector density variations have no effect on the efficiency. For beta particles, this efficiency is constant up to 0.0005 g/ density of gas. Furthermore, by increasing the air gap and Mylar thickness the efficiency will be decreased for both alpha and beta particles, while the variation of this value is remarkable for alpha particles.

Assessment of Morphological Changes in Breast Cancer Cells Following X-Ray Radiation Utilizing Digital Holographic Microscopy

2025-01-31T18:46:07+00:00

Purpose: Digital holographic microscopy, being a label-free and entirely non-invasive technique, proficiently facilitates the quantitative assessment of morphological alterations in living cells. The primary objective of this investigation is to scrutinize the capability of a digital holographic microscope in assessing the morphological transformations of cancer cells exposed to X-ray radiation.

Materials and Methods: The Michigan Cancer Foundation-7 (MCF7) cell line underwent exposure to X-ray radiation, administered in a singular fraction at a dose of 2 Gy. Subsequently, the MCF7 cell group was subjected to imaging through a digital holographic microscope. To scrutinize the morphological alterations between the radiation-exposed and control groups, the pertinent image parameters were extracted through the three-dimensional reconstruction of the microscopic images.

Results: The results indicate a significant increase in the morphological parameters of cells, encompassing volume, and roughness, subsequent to radiation exposure when contrasted with the control group. This observation signifies discernible alterations in the shape and roughness characteristics of MCF7 cells.

Conclusion: By extracting various parameters and broadening the spectrum of morphological and physical attributes, it becomes feasible to establish a more precise correlation between cellular conditions and the response to treatment. Such investigations pave the way for a more intricate exploration of cell morphology, enabling the identification of more specific parameters and distinctions in cellular response.

The Effects of Single and Bimetallic Silicon Composite Shields in Medical Imaging Methods: A Monte Carlo Study

2025-01-31T18:46:06+00:00

Purpose: Nowadays, the use of polymer composites with several metals to design and build new radiation composite shields with practical features in radiology is expanding.

Materials and Methods: Three metal oxides, including Bismuth oxide (Bi₂O₃), Tungsten oxide (WO₃), and Tin oxide (SnO₂) were used as mono-metal and bimetallic compound silicon matrixes for clarification of their practical use. Monte Carlo simulation methods were used to enter the specifications of each metal in combination with silicon. The mass attenuation coefficients of the mono- and bimetallic composites were calculated in the energy ranges of 40 to 150 KeV by classification to low/ medium/high groups.

Results: The results showed the beam reduction ability for both the mono- and the bimetallic composites. The mass attenuation coefficients of Bi₂O₃, WO₃, and SnO₂ at 80 KeV were 0.38, 0.33, and 0.57 cm²/gr, respectively. Moreover, the Bismuth-Tin bimetallic combination at low energies and the Bismuth-Tungsten at high energies had better attenuation than the other samples. To select bimetallic compounds with a high attenuation coefficient, it is better to match the energy used in the imaging method specifically. For example, in the 70-90 KeV energy range, the Sn-W combination had the highest beam attenuation coefficient.

Conclusion: The advantage of mono- and bimetallic shields in terms of energy attenuation amount depends on beam energy and shielding metal “K-absorption” edge. In comparing the attenuation of recorded beams in low, medium, and high ranges of energy, mono-metallic Bismuth shows higher attenuation coefficients than mono-metallic Tungsten and bi-metallic Bismuth–Tungsten. Dose reduction of the bi-metallic state of Bismuth - Tin was greater than that of mono-metallic Bismuth and Tin in low energies. Also, the attenuation of the Bi-Sn composite shield in low energy was the highest amount among all silicon composite shields.

High Energy X-Ray Detection by MicroPattern Gaseous Detector

2025-01-31T18:46:02+00:00

Purpose: The paper aims to discuss the response of the Micro-Mesh Gaseous Structure (Micromegas) detector to high-energy X-ray with 2.3 MeV energy using photon to neutron converters in addition to optimization of the detector components by Monte Carlo simulation.

Materials and Methods: Methods of using Micromegas are different in terms of energy and intensity of high-energy X-ray. Response of Micromegas detector to X-ray with 2.3 MeV by different photoneutron converters was calculated by Monte Carlo N Particle X-Version (MCNPX) code. The number of electrons in the drift and multiplication regions and the depth-dose in the various regions of the detector were measured to study the response of the Micromegas detector to high energy X-ray. Also, the thickness of the upper electrode, and the type of gas in the detector were studied and optimized.

Results: D₂O with 2×10^-5 efficiency is the best target to convert photons with 2.3 MeV energy to neutrons. It is the proper convertor to change the high energy X-ray into a photoneutron that can be detected by Micromegas. The optimum thickness of the upper electrode is 0.0026 cm for air and P10 gas in the detector.

Conclusion: The results show that this detector can detect high-energy X-rays with energy above 2 MeV. The Monte Carlo results showed the output current of the Micromegas detector is 5.12 pA per one input hard X-ray photon.

The Effect of Tumor Angiogenesis Agents on Tumor Growth Dynamics: A Mathematical Model

2025-01-31T18:45:58+00:00

Purpose: Tumor-induced angiogenesis is a dangerous state of the tumor growth process in which solid tumors have a blood supply. Modeling has been a very important tool in studying tumor growth and angiogenesis. In this paper, we developed a cancer model by introducing tumor angiogenesis agents to better highlight the role of these chemical substances in tumor-induced vascularization. Our model can reconstruct the transition from a pre-angiogenic to a post-angiogenic state.

Materials and Methods: The proposed model comprises five variables: host cells (normal cells), immune cells, tumor cells, endothelial cells, and tumor angiogenesis agents. Chaotic behavior in the production of different populations of cells during vascular growth may confer survival advantages to tumors. Our model has a chaotic regime, which is an indication of tumor-induced angiogenesis dynamics. The fixed points are analyzed biologically, and stability analysis is performed via their eigenvalues. We analyzed the model dynamics via observability and bifurcation analysis.

Results: The numerical simulations illustrate biological and clinical findings about vascular tumors. The results show that the proposed model with the existence of tumor angiogenesis agents could capture both avascular and vascular stages of tumor growth. There is no effect of tumor cell killing rate via immune cells on the system dynamics. However, the increase of inhibitory factors of tumor angiogenesis agents leads to the termination of chaos.

Conclusion: Our results show the ineffectiveness of targeted treatments on the immune system, which has been confirmed by many negative treatment methods in immunotherapies. Tumor-secreted inhibitor factors are essential to regulating the angiogenesis process. However, increasing inhibitor factors via anti-angiogenic drugs would be a more effective therapeutic approach to eradicate metastasis.

The Treatment Effect of Plantago Major on Lung Cancer Based on the Computed Tomography and Pathological Findings: A Case Report Study

2025-01-31T18:45:56+00:00

Purpose: Plantago Major (PM) is widely used for the treatment of different diseases due to several active compounds. Previous studies demonstrated the treatment effect of this plant on lung cancer cell lines. Here, we introduced a patient having lung cancer proved by Computed Tomography (CT) and pathological findings. The treatment effect of PM was assessed and presented based on CT and laboratory examinations for this patient as a first human case study.

Materials and Methods: A 64-year-old woman, with gastrointestinal bleeding as well as high Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) levels, was examined by the chest CT scan for suspicious lung cancer. Pathological findings confirmed the non-small cell lung cancer (adenocarcinoma, stage IIA). The patient consumed 150 ml of PM seeds extract (3-4 times daily) orally for about 4 months. Follow-up CT and laboratory examinations were performed after the treatment period to assess the effect of PM.

Results: The volume of the tumor was reduced by about 62% (based on CT imaging findings) after the treatment with PM. In addition, the laboratory examinations illustrate that ESR and CRP levels reduced remarkably (from 97 mm/h to 24 mm/h for ESR; from 36.8 mg/L to 1.2 mg/L for CRP) after the treatment.

Conclusion: Based on our human study, PM, as a natural compound with antioxidant, anti-inflammatory, and antibiotic characteristics, could have an anti-proliferative effect on non-small cell lung cancer. However, more follow-up examinations on big sample sizes are needed to assess the treatment effect of PM.

Advances in Radiation Protection in Oral and Dental Radiology: Pragmatic Approaches and Recent Innovations

2025-01-31T18:45:55+00:00

Purpose: The utilization of Ionizing Radiation (IR) in diagnostic dental techniques poses inherent risks, especially when patients are exposed to it repeatedly. Therefore, it is crucial to continuously evaluate and improve the measures taken to protect individuals from the potentially harmful effects of ionizing radiation in dental radiology. This study desires to assess the advancements made in recent years regarding ionizing radiation protection measures in the field of dental radiology.

Materials and Methods: A thorough review was conducted using prominent databases such as PubMed, Science Direct, and Dentistry and Oral Sciences Source (via EBSCOhost). The primary conclusions and relevant units of measurement are also included. According to the predefined inclusion and exclusion criteria, a total of 26 articles were systematically reviewed for this study.

Results: Recent data reveals the urgent need to update radiation protection guidelines to accommodate newer technologies like Cone Beam Computed Tomography (CBCT) and digital imaging. Digital intraoral X-ray technology has shown promising results in significantly reducing radiation exposure. To ensure standardized practices, Diagnostic Reference Levels (DRLs) have been defined for CBCT and must be established for different clinical indications. Moreover, advancements in nanotechnology provide potential opportunities for the production of radiation shielding supplies that are lighter and customizable. These innovative materials can prove invaluable for everyday use, offering enhanced protection during extended periods of physical activity. The review findings suggest that samples with nanostructures are more efficient at reducing X-ray energy. The research findings indicate that the implementation of a nanocomposite shield leads to a notable reduction in radiation dose, with a range of 15 to 35%. Given the increasing frequency of dental CBCT imaging and the unmatched dose levels compared to conventional dental radiography, it is imperative to set DRLs in this domain.

Conclusion: This literature review focuses on the most common types of radiation protection in dental radiology, aiming to demonstrate improved techniques for individual protection.

Effectiveness of Contrast Agents and Molecular Indicators in Alzheimer's Diagnosis through PET and SPECT Imaging on Animal Models: A Systematic Scoping Review

2025-01-31T18:45:52+00:00

Purpose: The importance of cognitive decline has increased due to population aging and lifestyle changes. A definitive diagnosis of Alzheimer's Disease (AD) is made only by postmortem histopathological examination, but in vivo imaging advances this diagnosis. The disease is associated with neuropathological features such as amyloid β (Aβ) plaques and Neurofibrillary Tangles (NFT) in the brain. The usefulness of contrast agents and compounds, such as SPECT and PET imaging, for the early identification of AD is investigated in this systematic scoping review. SPECT has been studied because it can yield reliable findings quickly, detect traces in data, and can link and evaluate the metabolism of mud and PET at high spatial resolution. The efficiency of molecular markers like tau protein, Translocator Protein (TSPO), and Amyloid β (Aβ), as well as contrast agents like [¹⁸F] fluorodeoxyglucose and [¹¹C] acetate. Early detection and diagnosis of AD is very important, but current research on the effectiveness of contrast agents and molecules is limited. To address this gap, we conducted a systematic scoping review on PET and SPECT imaging to evaluate the role of these factors and indicators in the diagnosis of this disorder.

Materials and Methods: A systematic search was conducted on August 30, 2023, in PubMed, using the PRISMA guidelines, without any time or language restrictions. The search was limited to PubMed because it is a comprehensive and extensive database in the medical sciences and the number of results we found there was sufficient. Three independent reviewers screened the studies based on criteria, and relevant data from the included articles were extracted and analyzed.

Results: As a result of the initial search, 172 original articles were included in the study. Finally, data from 116 studies were extracted. The most used contrast agents were [¹⁸F] fluorodeoxyglucose and its derivatives, [¹¹C] acetate, and chemicals based on iodine, respectively. The most often employed transgenic mouse strains in the studies were APP/PS1 and 5XFAD. On average, 23 animals were used in each study. Respectively, Amyloid beta, Tau protein, Translocator Protein (TSPO), Acetylcholinesterase (AChE), Monoamine Oxidase B (MAO-B), and Gonadotropin-Releasing Hormone Receptor (GnRHR) were identified the most as biomarkers in studies.

Conclusion: The study on PET and SPECT imaging for diagnosing AD has limitations, including the use of animal models and not evaluating the long-term effects or safety of contrast agents. Further research is needed to confirm these findings in clinical settings and assess the long-term impact of these contrast chemicals.

Small Magnets, Big Future: Low-Field MRI Technology and Clinical Utility

2025-01-31T18:45:50+00:00

Purpose: Despite the clinical advances made in magnetic resonance imaging with high static magnetic fields (1.5T and more), open MRI with low field (0.2-0.5T) has recently attracted the attention of researchers.

Low-field MRI (LF-MRI) has both advantages and disadvantages over high-field units. It enables the scanning of anxious patients and children who cannot tolerate enclosed high-field scanners due to discomfort. The open configuration of the LF-MRI provides a spacious examination environment. It also allows the safe imaging of metallic devices owing to the lower static field and radiofrequency. While image quality is degraded compared to high-field MRI due to a lower signal-to-noise ratio, technological advances may help address this limitation.

This review aims to provide a comprehensive outline of the current applications, technical aspects, and evidence supporting the diagnostic accuracy of Low-Field MRI.

Materials and Methods: A literature search was conducted in Google Scholar and PubMed from 2021 to the oresent using the search term "low field MRI" limited to the title. Studies were excluded if only on high-field MRI, not in English, or conference abstracts without full text. After applying exclusion criteria, 32 relevant articles remained for analysis.

Results: The results showed that portable low-field MRI expanded the availability of MRI beyond fixed facilities. One study found that 0.55T MRI had an accuracy similar to 1.5T for microbleed detection, suggesting its potential as an efficient alternative for stroke diagnosis. The literature has demonstrated the utility of low-field MRI in applications such as musculoskeletal, breast, and abdominal imaging.

Conclusion: In conclusion, these studies demonstrated the potential of low-field MRI as a cost-efficient alternative to high-field MRI for several clinical applications. The reduced costs and accessibility afforded by low-field designs have positioned this technology to increase diagnostic MRI access globally. However, further validation of diagnostic performance and cost-utility analyses accounting for accuracy are still needed.

Sensitivity Improvement of Optical Computed Tomography Scanners for Scanning Gel Dosimeters

2025-01-31T18:45:48+00:00

Despite recent advances in Optical Computed Tomography (OCT) systems, there is skepticism regarding the sensitivity and performance of these systems for gel dosimetry. The optical sensitivity of gel dosimeters changes at different wavelengths and their maximum sensitivities are achieved at the particular wavelengths. Therefore, the optimal wavelength must be used for optical scanning of the gel dosimeters. Since OCT systems are used for scanning different gel dosimeters, a mono-energy light source would not lead to optimal performance. Commercially available multi-wavelength lasers provide a variety of power and wavelength ranges. Adopting multi-wavelength light sources instead of single-wavelength laser sources increases the price of the system by less than 5%, which is justifiable and ignorable due to the considerably increased performance and sensitivity. In the proposed approach, only the wavelength of the scanning beam would be optimized based on the gel dosimeter type. The rules for determining the opacity of the beam path across the sample are the same for all gel dosimeters. Therefore, the change in wavelength of the scanning beam didn’t change the scanning procedure and there is no additional complexity in the OCTs with the multi-wavelength light sources.