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Showing papers in "Iranian Journal of Medical Physics in 2021"


Journal ArticleDOI
TL;DR: In this article, a study was conducted on two new low-density bulk metallic glass (BMG) based BMGs (i.e., Ti32.8Zr30.2Ni5.3Cu9Be22.7 and Ti31.9Zr33.4Fe4Cu8.7Be22) to investigate their photon and fast neutron shielding capacities.
Abstract: Introduction: Low-density bulk metallic glass (BMG) with good structural characteristics has the potential of being used for structural radiation shielding purposes. This study was conducted on two new low-density titanium (Ti)-based BMGs (i.e., Ti32.8Zr30.2Ni5.3Cu9Be22.7 and Ti31.9Zr33.4Fe4Cu8.7Be22) to investigate their photon and fast neutron shielding capacities. Material and Methods: The mass attenuation coefficients, half-value layers, effective atomic numbers, and exposure buildup factors of the two BMGs were calculated at the photon energy values of 15 keV and 15 MeV. Computation of mass attenuation coefficients and effective atomic numbers was accomplished using the XCOM and auto-Zeff software, respectively. In addition, the geometric progression procedure-based computer code EXABCal was used for calculating the exposure buildup factors of BMG. The fast neutron removal cross-sections were also calculated for the two BMGs. The calculated photon and fast neutron shielding parameters for BMGs were compared with those of lead (Pb), heavy concrete, and some recently developed glass shielding materials and then analyzed according to their elemental compositions. Results: The results showed that though Pb had a better photon shielding capacity, Ti-BMG attenuated photons better than heavy concrete. Furthermore, BMG had a higher neutron removal cross-section, compared to heavy concrete and some recently developed glass shielding materials. The neutron removal cross-sections of Ti32.8Zr30.2Ni5.3Cu9Be22.7 and Ti31.9Zr33.4Fe4Cu8.7Be22 were obtained as 0.1663 and 0.1645 cm-1,respectively. Conclusion: his study revealed that Ti-based BMG with high strength and low density have potential applications in high-radiation environments, particularly in nuclear engineering for source and structural shielding.

16 citations


Journal ArticleDOI
TL;DR: The soft gamma ray radiation has harmful effect of physiological for reproductive system and avoid the exposure for long time about soft ionizing radiation from therapy of gamma ray or gamma ray emitted from environmental media.
Abstract: Introduction: The present study investigatedthe risks of ionizing radiation on sperm counts in chronic doses and compared the findings with previous results in similar and different conditions to minimize oxidant stress on sperm parameters rather than using black seed oil. Material and Methods: Twenty rats were used in experimental designs 1 and allocated unordered to four groups. Each group included five. The ranges of 2-3 months and 170 -200 g, respectively .The healthy rats were obtained from the University of Mosul ,Iraq .Experimental design 2, was conducted on 50 rats .The rats were exposed to three different doses for 30 days similar to those of experimental design 1. Oral black seed oil was administrated a dose of 20 mg/kg in group 2 . Results: In experimental design 1, there was a significant decrease in sperm count, live sperm percentage and normal sperm percentages respectively. However a significant increase was observed in dead sperm and abnormal sperm percentages in experimental design 1.The administration of black seed oil in excremental design 2 improved all the parameters with reducing abnormal and dead sperm counts rather than increasing normal and live sperm counts at all doses . Conclusion: The use of black seed reduce the oxidative stress caused by low dose gamma radiation .Therefore , this substance can be used as a therapeutic option for the treatment of several type of cancer especially those under the treatment of low dose gamma radiation through enhancement of protection for a long time.

2 citations


Journal ArticleDOI
TL;DR: The proposed image based CNN algorithm showed high accuracy in recognizing LAA boundaries in the echocardiographic images and can be used in developing algorithms for automated analysis of the area of the LAA that is used for device sizing and procedural planning in the L AA occlusion procedures.
Abstract: Introduction: Atrial fibrillation is the most common cardiac arrhythmia of clinical significance and is associated with increased risk of stroke through thrombus formation primarily in the left atrial appendage (LAA). LAA occlusion using a purpose-built device is a growing procedure. In this study, we aimed to develop a computer aided diagnostic system for recognition of the LAA in echocardiographic images.Material and methods: 3D echocardiographic images of the LAA of 26 patients who were successfully treated with an LAA occluder were used in this study. 208 3D derived 2D images in the axial plane were derived from each 3D dataset. 562 images in which the LAA boundaries were highly recognizable were selected. The proposed convolutional neural network (CNN) in this study is based on an open source object identification and classification platform that is compiled under the YOLO algorithm. 419 and 143 images were used for training and testing the algorithm respectively. Results: Algorithm performance on identifying the LAA region on the set of 143 images was compared to the traced regions on the same images by the expert in echocardiography using intersection over union (IOU) algorithm. The algorithm was able to correctly identify the LAA region in all 143 examined images with average IOU of 90.7%. Conclusion: The proposed image based CNN algorithm in this study showed high accuracy in recognizing LAA boundaries in the echocardiographic images. The method can be used in developing algorithms for automated analysis of the area of the LAA that is used for device sizing and procedural planning in the LAA occlusion procedures.

2 citations


Journal ArticleDOI
TL;DR: The correction method used in the present study could enhance the accuracy of dose estimated by TLDs in fast neutron fields by modifying the response in different neutron fields.
Abstract: Introduction: Neutron dosimetry is a challenging subject in radiation protection. Responses of neutron dosimeters mostly depend on the neutron energy spectrum. Dosimeter response corresponding to a dose-equivalent in the calibration field is different from responses in other neutron fields. Consequently, the dose estimated by neutron dosimeters may be associated with great uncertainty. Therefore, the present study aimed to modify the response in different neutron fields in order to reduce this uncertainty. Material and Methods: Thermo-luminescent dosimeters (TLDs) are widely used to determine neutron dose-equivalent. In the present study, a set of TLD-600 and TLD-700 dosimeters included in a TLD card was utilized to determine the response to “fast” neutrons of 241Am-Be,252Cf, and 239Pu-Be standard fields in four dose-equivalents of 5, 10, 15, and 20 mSv. Meanwhile, 241Am-Be was regarded as the calibration field. Results: As evidenced by the obtained results, for equal dose-equivalents, the original responses in 252Cf and 239Pu-Be fields are smaller, compared to those in the 241Am-Be filed. The maximum discrepancies were obtained at 26.8% and 42.5% occurring at 20 and 5 mSv, respectively. After the application of a correction factor equal to the average of relative responses (i.e., in 241Am-Be to two other fields) corresponding to all dose-equivalents considered, these differences reduced to 12.4% and 21.7%. Conclusion: It can be concluded that the correction method used in the present study could enhance the accuracy of dose estimated by TLDs in fast neutron fields.

2 citations


Journal ArticleDOI
TL;DR: Results showed that the MIT source is well suited to treat deep lung tumors while maintaining the OARs’ dose within the threshold dose, and the implemented model was successful in calculating the dose to organs using BNCT.
Abstract: Introduction: Boron neutron capture therapy (BNCT) is recommended to treat glioblastoma. It is well known that neutrons are more effective treatment than photons to treat hypoxic tumors due to interaction with the nucleus and production of heavy particles. Objective: To evaluate the suitability of BNCT for treating lung cancer, neutron dose distributions was calculated in lung tumor volume and in peripheral organs at risk (OARs).Materials and Methods: Dose distribution to treat lung cancer was calculated by MCNPX code. An elliptical tumor with volume of 27cm3 was centered in the left lung of ORNL phantom and was irradiated with a rectangular field of neutron. Recommended neutron spectrums of MIT and CNEA-MEC were used as a neutron source. The tumor was loaded with different concentrations of Boron 0, 10, 30 and 60 ppm to evaluate the delivered dose to OARs. Results: neutron absorbed dose rate in the tumor was 2.2×10-3, 2.6×10-3, 3.4×10-3 and 4.7×10-3 Gy/s for boron concentrations of 0, 10, 30 and 60 ppm, respectively in MIT. Moreover, the similar results in CNEA-MEC was 1.2×10-3, 1.6×10-3, 2.5×10-3 and 3.7×10-3 Gy/s. Among all, heart absorbed the maximum neutron dose rate of 1.7×10-4 and 1.6×10-4 Gy/s in MIT and CNEA, respectively. For all energy’s bins of spectrums, the neutrons flux is decreased as it penetrates the lung. Conclusion: The implemented model was successful in calculating the dose to organs using BNCT. An Increase in boron concentrations in tumor results in an increase in the absorbed doses while dose uniformity deteriorates. Results showed that the MIT source is well suited to treat deep lung tumors while maintaining the OARs’ dose within the threshold dose.

2 citations


Journal ArticleDOI
TL;DR: In this paper, the gamma spectrometer system was used for determining the activity concentrations of naturally occurring radionuclides (i.e., 226Ra, 232Th, and 40K) in surface soil samples collected from Mazandaran province, Iran.
Abstract: Introduction: This paper aimed to outline the procedure for determining the activity concentrations of naturally occurring radionuclides (i.e., 226Ra, 232Th, and 40K) in surface soil samples collected from Mazandaran province, Iran. Material and Methods: In total, 61 samples were collected between longitude 50˚ 34′ and 54˚ 10′ east and latitude 35˚ 47′ and 36˚ 35′ north from uncultivated locations of Mazandaran province, Iran. The measurements were performed by the gamma spectrometry system using a High Purity Germanium detector. Results: The mean levels of 226Ra, 232Th, and 40K were found to be 20 Bqkg-1 (without considering high-level areas), 33 Bqkg-1, and 421 Bqkg-1, respectively. The results were compared with those of different countries across the world. The radiological hazard to the natural radioactivity was assessed by calculating the absorbed dose rate, the radium equivalent activity, the external and internal hazard indices, and the outdoor and indoor annual effective dose rate. The mean radium equivalent without considering three high-level areas was estimated at 100.8 Bqkg-1. Conclusion: Results indicated that no radiological risk may threat the residents of the areas under study, except for regions near the hot spring in Sadat Shahr and Lavich, Iran. Without considering high-level areas, the mean radium equivalent activity was 100.8 Bqkg-1 that was about 73% lower than the permissible maximum. Moreover, internal and external hazard indices were less than the unit. The mean absorbed dose rate, as well as the outdoor and indoor annual effective dose rates were 48.56 nGyh-1, 238.4 µSv y-1, and 292.6 µSv y-1, respectively.

1 citations


Journal ArticleDOI
TL;DR: The results showed that the cosine similarities between the muscles of each person could lead to the training of the neural network and the classification of individuals at different levels of skill.
Abstract: Introduction: “Muscular synergy” is one of the methods for determining the relationship between the central nervous system and muscles which are involved in performing a specific movement. To perform each movement, certain patterns are followed through the central nervous system that control the number of synergies, and these patterns are modified and optimized during the skill. Thepresent study aimed to classify basketball athletes based on muscular synergy analysis. Material and Methods: For the purpose of the study, the electromyography (EMG) signals of six dominant hand muscles were recorded during performing three basketball skills. Subsequently, synergy was identified using the non-negative matrix factorization method. In the next stage, the cosine similarity feature was calculated separately; furthermore, the time and frequency of the main signal were analyzed, and the neural network was evaluated using MATLAB software. Results: The result of the classification was obtained by applying the dimensioned reduced matrix of all the existing features with a reliability of 73.68%. In addition, the results demonstrated that the cosine similarities between the muscles of each person could lead to the training of the neural network and classification of individuals at different levels of skill. Conclusion: The present study suggested a new idea regarding synergistic features for classifying athletes based on EMG signal. However, the use of time and frequency features only facilitated differentiation between a maximum of two groups.

1 citations


Journal ArticleDOI
TL;DR: It is suggested that Long-time fluoroscopy in electrophysiological study may cause a significant increase of apoptosis in peripheral blood lymphocyte of patients that treated with this procedure.
Abstract: Introduction: The long-term use of fluoroscopy in cardiac interventional procedures increases the patient dose and causes severe skin reactions, which lead to growing concern. The aim of the present study was to evaluate the risk and the effect of X-ray irradiation on apoptosis in the peripheral blood lymphocytes of patients treated with ablation in electrophysiological studies. Material and Methods: A total of 30 patients who underwent ablation therapy participated in this study. The absorbed dose in the given area was measured by a thermos luminescent dosimeter (TLD). The duration of dose delivery, absorbed dose by the apparatus, and dose area product (DAP) factor were measured for each patient. The skin changes were observed within the 1st day to 5th week after the operation. Blood sampling was conducted (before and 24 h after the treatment), and then, flow cytometry was performed to investigate the apoptotic changes in the blood lymphocytes. Results: The statistical analysis showed that there was a significant difference in the apoptosis of patient blood lymphocytes before irradiation and following that (p <0.05). There was a correlation between the amount of DAP and TLD dose (p <0.001). Furthermore, a correlation was observed between the total apoptosis and fluoroscopic time. The patient radiation dose in the ablation test was not in the threshold level required to create skin erythema. Conclusion: The results of the present study revealed that the use of long-time fluoroscopy in electrophysiological studies may cause a significant increase of apoptosis in the peripheral blood lymphocyte of patients treated using this procedure.

1 citations


Journal ArticleDOI
TL;DR: The most left-sided breast cancer patients who treated with D IBH technique were getting sufficient benefits of radiotherapy and DIBH was a comprehensive strategy for reducing cardiac doses during radiotherapy treatment.
Abstract: Introduction: Most women with left-sided breast cancer are at an increased risk of heartmorbidity and mortality from the adjuvant radiotherapy due to an increase in heart absorbed dose during radiotherapy treatment. This study aimed to compare free-breathing intensity-modulated radiotherapy (FB-IMRT) and three-dimensional conformal deep inspiration breath-hold (3DCRT-DIBH) techniques in terms of the cardiac dose. Material and Methods: In total, 15 women with left-sided breast cancer underwent FB and DIBH computed tomography (CT) scans in the same supine position. For DIBH CT, 3D-CRT plans were created using two opposing wedged tangential fields and for FB-CT, 4-5 IMRT optimized tangential fields were created. All plans were evaluated using the dose-volume histogram. The data were analyzed in SPSS software version 20 (IBM, IL). Results: The FB-IMRT plans were more homogeneous and had more dose coverage and fewer hotspots, than the 3DCRT-DIBH plans; however, the planning target volume V95% was clinically acceptable for both techniques. Furthermore, the 3DCRT-DIBH plans were much faster and require fewer monitor units. A significantly lower mean dose of heart, left lung, left anterior descending coronary artery, right lung, and V10% left lung were observed in 3DCRT-DIBH plans, compared to FB-IMRT plans. Moreover, FB-IMRT plans showed a significant further dose reduction in heart V25% and V30%. Conclusion: The majority of the patients with left-sided breast cancer who treated with the DIBH technique were getting sufficient benefits of radiotherapy, and DIBH was a comprehensive strategy for reducing cardiac doses during radiotherapy treatment.