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Introduction: Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) are primary techniques for rectal cancer treatment. In radiotherapy planning, collimator rotation is a crucial parameter, and its adjustments can lead to dosimetric variations. This study examined the influence of collimator rotation on dosimetric outcomes for different IMRT and VMAT plans for rectal cancer. Methods: CT images from 20 male rectal cancer patients were used for IMRT and VMAT treatment planning with varying collimator angles. Nine IMRT techniques (5, 7, and 9 coplanar fields with collimator angles of 0°, 45°, and 90°) and six VMAT techniques (1 and 2 full coplanar arcs with collimator angles of 0°, 45°, and 90°) were planned for each patient. Dosimetric results for target tissue (conformity index [CI] and homogeneity index [HI]) and sparing of organs at risk (OARs) (parameters from OARs dose - volume histograms [DVH]) were analyzed and compared, along with radiobiological findings. Results: The 7-fields IMRT technique showed lower bladder doses (V40Gy, V45Gy) unaffected by collimator rotation. The 9 - fields IMRT and 2 - arcs VMAT (excluding the 90 - degree collimator) exhibited the lowest V35Gy and V45Gy. A 90 - degree collimator rotation in 2 - arcs VMAT significantly increased small bowel and bladder V45Gy, femoral head doses, and HI values. Radiobiologically, the 90 - degree rotation adversely affected small bowel NTCP (normal tissue complication probability). No superiority was observed for a 45 - degree collimator rotation over 0 or 30 degrees in VMAT techniques. Conclusions: Collimator rotation minimally impacted dosimetric parameters in IMRT planning but significantly affected VMAT techniques. A 90 - degree rotation in VMAT, especially in a 2 - full arc technique, negatively impacted PTV homogeneity index, bladder dose, and small bowel NTCP. Other evaluated collimator angles did not significantly affect VMAT dosimetrical or radiobiological outcomes. [ABSTRACT FROM AUTHOR]

Background: Approximately 50% of dental amalgam is elemental mercury by weight. Accumulating body of evidence now shows that not only static magnetic fields (SMF) but both ionizing and non-ionizing electromagnetic radiations can increase the rate of mercury release from dental amalgam fillings. Iranian scientists firstly addressed this issue in 2008 but more than 10 years later, it became viral worldwide. Objective: This review was aimed at evaluating available data on the magnitude of the effects of different physical stressors (excluding chewing and brushing) on the release of toxic mercury from dental amalgam fillings and microleakage. Material and Methods: The papers reviewed in this study were searched from PubMed, Google Scholar, and Scopus (up to 1 December 2019). The keywords were identified from our initial research matching them with those existing on the database of Medical Subject Headings (MeSH). The non-English papers and other types of articles were not included in this review. Results: Our review shows that exposure to static magnetic fields (SMF) such as those generated by MRI, electromagnetic fields (EMF) such as those produced by mobile phones; ionizing electromagnetic radiations such as X-rays and non- Ionizing electromagnetic radiation such as lasers and light cure devices can significantly increase the release of mercury from dental amalgam restorations and/or cause microleakage. Conclusion: The results of this review show that a wide variety of physical stressors ranging from non-ionizing electromagnetic fields to ionizing radiations can significantly accelerate the release of mercury from amalgam and cause microleakage. [ABSTRACT FROM AUTHOR]

Background: Computed tomography (CT) is a routine procedure for diagnosing using ionization radiation which has hazardous effects especially on sensitive organs. Objective: The aim of this study was to quantify the dose reduction effect of lead apron shielding on the testicular region during routine chest CT scans. Material and Methods: In this measurement study, the routine chest CT examinations were performed for 30 male patients with common lead aprons folded and positioned in testis regions. The patient's mean body mass index (BMI) was 26.2 ± 4.6 kg/m². To calculate the doses at testis region, three thermoluminescent dosimeters (TLD-100) were attached at the top surface of the apron as an indicator of the doses without shielding, and three TLDs under the apron for doses with shielding. The TLD readouts were compared using SPSS software (Wilcoxon test) version 16. Results: The radiation dose in the testicular regions was reduced from 0.46 ± 0.04 to 0.20 ± 0.04 mGy in the presence of lead apron shielding (p < 0.001), the reduction was equal to 56%. Furthermore, the heritable risk probability was obtained at 2.0 ×10-5 % and 4.6 ×10-5 % for the patients using the lead apron shield versus without shield, respectively. Conclusion: Applying common lead aprons as shielding in the testis regions of male patients undergoing chest CT scans can reduce the radiation doses significantly. Therefore, this shield can be recommended for routine chest CT examinations. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the dosimetric parameters of level II lymph nodes in chest wall three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) of mastectomy patients using dual-isocentric (DIT) and mono-isocentric techniques (MIT). Materials and methods: Computed tomography (CT) images of 20 mastectomy patients undergoing chest wall external radiotherapy were used as the input data for the abovementioned techniques. Selected dosimetric parameters were calculated for the axillary level I–III lymph nodes, chest wall, heart and lung. Paired t-test statistical analysis was used for comparing the results of MIT and DIT in both 3D-CRT and IMRT methods. Results: There were significant differences in Dmin (minimum dose), Dmax (maximum dose) and maximum–minimum dose between MIT and DIT techniques (13, −8·6, −52·2% differences for Dmin, Dmax and maximum–minimum, respectively) in IMRT. There were also significant differences for Dmean (mean dose), Dmax and maximum–minimum dose (7·8, −11·4, −44·6% differences in Dmean, Dmax and maximum–minimum, respectively) in 3D-CRT (p < 0·05). In addition, there were not any differences in the dosimetric parameters for heart, lung and level I and III lymph nodes. Conclusion: In both 3D-CRT and IMRT methods, level II lymph node dose distribution in MIT was closer to the prescribed dose compared with DIT due to the position of these nodes in the field junction area. To achieve a better dose homogeneity, it could be recommended to use MIT instead of DIT in 3D-CRT and IMRT for mastectomy patients. [ABSTRACT FROM AUTHOR]

Introduction and purpose: During the radiation therapy of tumoral breast, the contralateral breast (CB) will receive scattered doses. In the present study, the photon and thermal neutron dose values received by CB surface during breast cancer radiation therapy were measured. Materials and methods: The right breast region of RANDO phantom was considered as CB, and the measurements of photon and thermal neutron dose values were carried out on this region surface. The phantom was irradiated with 18 MV photon beams, and the dose values were measured with thermoluminescent dosimeter (TLD-600 and TLD-700) chips for 11 × 13, 11 × 17 and 11 × 21 cm2 field sizes in the presence of physical and dynamic wedges. Results: The total dose values (photon + thermal neutron) received by the CB surface in the presence of physical wedge were 12·06%, 15·75% and 33·40% of the prescribed dose, respectively, for 11 × 13, 11 × 17 and 11 × 21 cm2 field sizes. The corresponding dose values for dynamic wedge were 9·18%, 12·92% and 29·26% of the prescribed dose, respectively. Moreover, the results showed that treatment field size and wedge type affect the received photon and thermal neutron doses at CB surface. Conclusion: According to our results, the total dose values received at CB surface during breast cancer radiotherapy with high-energy photon beams are remarkable. In addition, the dose values received at CB surface when using a physical wedge were greater than when using a dynamic wedge, especially for medial tangential fields. [ABSTRACT FROM AUTHOR]

Introduction The main purpose of this study was to determine the diagnostic reference level (DRL) for routine digital radiography examinations in Mazandaran province. Materials and methods Thirteen digital radiographic examinations at 18 high-patient-load radiography centres were investigated. The indirect dosimetry method was performed based on the IAEA report. Average entrance skin dose (ESD) and the third quartile of ESD as the DRL were evaluated from the measurement made by a semiconductor dosemeter. Results DRL for the examinations of digital radiography was obtained as: Skull (postero-anterior [PA]): 2.2, skull (lateral [LAT]): 2.4, cervical spine (antero-posterior [AP]): 1.6, cervical spine (LAT): 1.7, thoracic spine (AP): 3.6, thoracic spine (LAT): 9.9, lumbar spine (AP): 5.3, lumbar spine (LAT): 11.8, chest (PA): 1.4, chest (LAT): 2.1, abdomen (AP): 4.3, pelvis (AP): 3.2 and hip (AP): 2.1 mGy. Conclusion Although DRL was not higher compared with the international organisations' levels, it can be reduced by adequate training of radiographers. [ABSTRACT FROM AUTHOR]

Introduction: Idiopathic generalised epilepsy (IGE) refers to a group of epilepsies resulting from the activation of neurons in the whole brain. This study aimed to evaluate the metabolite changes in thalamus as diagnostic biomarkers in IGE patients compared to healthy individuals using magnetic resonance spectroscopy (MRS) technique. Methods: The MRS was performed on 35 IGE patients (26 women and 11 men) with average age of 32 (ranged from 18 to 43) and 35 healthy individuals (13 women and 22 men) with average age of 31 (ranged from 21 to 50) as the control group. The levels of N-acetylaspartate (NAA), creatine (Cr) and choline (Cho) were measured using MRS. The NAA/Cr and NAA/Cho ratios were calculated for all participants. These values were statistically compared using t-test between the groups. Results: The NAA had significant lower values in IGE patients, 9.6 (SD = 0.8) and 9.9 (SD = 0.7) for right and left thalamus, respectively, compared to 10.9 (SD = 0.9) and 10.7 (SD = 0.9) in control group. The Cr values in the left side of thalamus were significantly higher in IGE patients (6.7 [SD = 0.8] versus 5.8 [SD = 0.5]); however, there was no difference in right thalamus. Measurements showed no difference for amounts of Cho between the groups in both sides of thalamus. The NAA/Cr ratio was 1.48 (SD = 0.14) and 1.48 (SD = 0.16) for right and left thalamus, respectively, in IGE patients in comparison with 1.83 (SD = 0.2) and 1.86 (SD = 0.26) in controls. There was no meaningful variation between the NAA/Cho ratio of the right and left thalamus among the groups. Conclusion: Thalamic NAA, Cr and NAA/Cr ratio values in IGE patients showed statistical differences compared to healthy individuals. Evaluating metabolites variations in thalamus using MRS is suggested for differentiating IGE patients from healthy individuals. [ABSTRACT FROM AUTHOR]

Background: Radiotherapy is a main method for the treatment of breast cancer. This study aimed to measure the absorbed dose of thyroid gland using Gafchromic EBT2 film during breast cancer radiotherapy. In addition, the relationship between the absorbed dose and thyroid hormone levels was evaluated. Methods: Forty-six breast cancer patients, with the age ranged between 25 and 35 years, undergoing external radiotherapy were studied. The patients were treated with 6 and 18 MV X-ray beams, and the absorbed thyroid dose was measured by EBT2 film. Thyroid hormone levels, thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxin (T4), were measured before and after the radiotherapy. Pearson's, Spearman's, and Chi-square tests were performed to evaluate the correlation between the thyroid dose and hormone levels. Results: The mean thyroid dose was 26 ± 9.45 cGy with the range of 7.85–48.35 cGy. There were not any significant differences at thyroid hormone levels between preradiotherapy and postradiotherapy (P > 0.05). There was a significant relationship between increased thyroid absorbed dose and changes in TSH and T4 levels (P < 0.05), but it was not significant in T3 level (P = 0.1). Conclusion: Regarding the results, the thyroid absorbed dose can have an effect on its function. Therefore, the thyroid gland should be considered as an organ at risk in breast cancer radiotherapy. [ABSTRACT FROM AUTHOR]

Dry eye disease (DED) is a common ocular condition characterized by chronic inflammation and tear film disruption. It affects millions of people worldwide, causing significant eye discomfort and vision disturbances. Despite its prevalence, DED remains a complex condition that is not yet fully understood. It can arise from various ocular pathologies, including endocrinological disorders such as diabetes and Graves' orbitopathy. Natural products, including plant- and blood-based therapies, have shown promise in alleviating DED symptoms and may represent effective therapeutic approaches. In this study, we review recent research on natural product treatments for DED, focusing on blood-derived therapies (e.g., autologous serum, albumin serum, and allogeneic serum) and plant-based compounds such as omega-3 fatty acids (O3FA), omega-6 fatty acids (O6FA), antioxidants, polyphenols, and flavonoids. Additionally, we examine the efficacy, mechanisms of action, and delivery systems of these treatments, highlighting the potential of blood-derived therapies, polyphenols, and flavonoids to improve or treat DED through multiple mechanisms. However, the use of these natural products as instilled drugs is limited by challenges such as solubility, stability, and biological barriers. Finally, we discuss drug delivery systems and structural modifications designed to enhance the therapeutic effects of these treatments, emphasizing their potential in managing DED., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: The biosynthesis of tumor-associated sialoglycans involves Sialyltransferases expressed in cancer cells differentially. The current review aspires to bridge the existing knowledge gaps by consolidating evidence regarding the role of Sialyltransferases in gynecological malignant tumors (ovarian, cervix, endometrial, and breast)., Methods: In this systematic review, we searched databases, including PubMed, Embase, Web of Science, Scopus and Cochrane Library. Twenty-two high-quality articles were selected out of 559 researched studies using radiomics quality score (RQS) tools., Results: Our findings indicated that 7 articles were related to Sialyltransferases in ovarian cancer, in which 6 studies was examined only ST6Gal-I and one study examined the ST3Gal-I, ST3Gal-II, ST3Gal-III, ST3Gal-IV, ST3Gal-VI, and ST3Gal-6. In addition, 5 articles were related to Sialyltransferases in cervix cancer (ST6Gal-I), 3 articles to endometrial cancer (ST6Gal-I, ST3Gal-III, ST3Gal-IV, and ST3Gal-6), and 7 articles to breast cancer (ST6Gal-I gene in 5 studies, ST6GAL-II gene in one study, and ST8SIA1 and ST3GAL-V genes in one study)., Conclusion: ST6Gal-I gene expression occurs at a high speed in ovarian, cervix, endometrial, and breast cancers, leading to metastasis to distant cells, cell destruction, cell invasion, and reduced patient survival., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier GmbH. All rights reserved.)