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INTRODUCTION: Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) are the main radiotherapy techniques for treating and managing rectal cancer. Collimator rotation is one of the crucial parameters in radiotherapy planning, and its alteration can cause dosimetric variations. This study assessed the effect of collimator rotation on the dosimetric results of various IMRT and VMAT plans for rectal cancer. MATERIALS AND METHODS: Computed tomography (CT) images of 20 male patients with rectal cancer were utilized for IMRT and VMAT treatment planning with various collimator angles. Nine different IMRT techniques (5, 7, and 9 coplanar fields with collimator angles of 0°, 45°, and 90°) and six different VMAT techniques (1 and 2 full coplanar arcs with collimator angles of 0°, 45°, and 90°) were planned for each patient. The dosimetric results of various treatment techniques for target tissue (conformity index [CI] and homogeneity index [HI]) and organs at risk (OARs) sparing (parameters obtained from OARs dose-volume histograms [DVH]) as well as radiobiological findings were analyzed and compared. RESULTS: The 7-fields IMRT technique demonstrated lower bladder doses (V40Gy, V45Gy), unaffected by collimator rotation. The 9-fields IMRT and 2-arcs VMAT (excluding the 90-degree collimator) had 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 had adverse effects on small bowel NTCP (normal tissue complication probability). No superiority was found for a 45-degree collimator rotation over 0 or 30 degrees in VMAT techniques. CONCLUSION: Collimator rotation had minimal impact on dosimetric parameters in IMRT planning but is significant in VMAT techniques. A 90-degree rotation in VMAT, particularly in a 2-full arc technique, adversely affects PTV homogeneity index, bladder dose, and small bowel NTCP. Other evaluated collimator angles did not significantly affect VMAT dosimetrical or radiobiological outcomes.
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OBJECTIVES: To evaluate skin dose differences between TPS (treatment planning system) calculations and TLD (thermo-luminescent dosimeters) measurements along with the dosimetric effect of applicator misplacement for patients diagnosed with gynecological (GYN) cancers undergoing brachytherapy. METHODS: The skin doses were measured using TLDs attached in different locations on patients' skin in pelvic regions (anterior, left, and right) for 20 patients, as well as on a phantom. In addition, the applicator surface dose was calculated with TLDs attached to the applicator. The measured doses were compared with TPS calculations to find TPS accuracy. For the phantom, different applicator shifts were applied to find the effect of applicator misplacement on the surface dose. RESULTS: The mean absolute dose differences between the TPS and TLDs results for anterior, left, and right points were 3.14±1.03, 6.25±1.88, and 6.20±1.97 %, respectively. The mean difference on the applicator surface was obtained 1.92±0.46 %. Applicator misplacements of 0.5, 2, and 4âcm (average of three locations) resulted in 9, 36, and 61%, dose errors respectively. CONCLUSIONS: The surface/skin differences between the calculations and measurements are higher in the left and right regions, which relate to the higher uncertainty of TPS dose calculation in these regions. Furthermore, applicator misplacements can result in high skin dose variations, therefore it can be an appropriate quality assurance method for future research.
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Braquiterapia , Braquiterapia/efeitos adversos , Braquiterapia/métodos , Humanos , Imagens de Fantasmas , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodosRESUMO
BACKGROUND: Rectum and bladder are hallow structures and considered as critical organs in prostate cancer intensity modulated radiotherapy (IMRT). Therefore, dose received by these organ walls must be considered for prediction of radiobiological effects. Contouring the real organ walls is quite difficult and time consuming in CT/MRI images, so the easy contouring artificial walls with uniform thickness could be appropriated alternatives. OBJECTIVE: To compare reconstructed artificial walls with real walls of bladder and rectum in common prostate IMRT techniques based on dose volume-histograms (DVHs) derived from artificial and real walls. METHODS: Artificial walls were reconstructed with 2-10âmm and 2-8âmm thicknesses for bladder and rectum, respectively. Four common IMRT techniques were applied to each patient. Spearman correlation was used to find the relation between the DVHs of true walls with artificial walls and whole organs. Monte Carlo (MC) simulations of the IMRT techniques and dosimetric comparison were also performed on a standard patient data. RESULTS: The 2âmm thickness artificial walls showed the minimum differences with the true bladder and rectum walls based on absolute evaluations (the maximum differenceâ<â10cc and standard deviationâ<â15cc). However, relative evaluations showed that all the artificial walls had high correlations with real walls for selecting dose volume parameters. There was also good agreement between the treatment planning system and MC simulations results. CONCLUSION: The DVH of whole organs was not a good surrogate of the true wall. The 2âmm artificial walls can be regarded as good alternatives for both of rectum and bladder. However, in relative dose evaluations all studied artificial walls were appropriate.
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Órgãos em Risco/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Reto/diagnóstico por imagem , Bexiga Urinária/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Método de Monte Carlo , Radiometria , Dosagem Radioterapêutica , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodosRESUMO
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.
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The monoisocentric (MIT) and dual isocentric (DIT) techniques are compared for the mastectomy patients undergoing chest wall radiotherapy, and a new practical method is suggested for determining the dose calculation reference point to be used in the MIT. Data of 18 mastectomy patients having chest wall radiotherapy were used. To find the appropriate dose calculation reference point for the MIT, the target tissue was divided into nine regions with 17 points as the appropriate candidates. After finding the best reference point for the MIT, dose calculations were made for each patient based on the MIT and DIT to determine the dose distributions of the target volume and organs at risk. The lateral component of the dose calculation reference point was found to be located at one-third of the distance between the geometrical center and the lateral border of the chest wall in the lateral direction toward the outer border. The longitudinal component of this point was found to be located at the geometrical center of the chest wall with a depth located around 2-3 cm under the patients' skin. There was no significant difference between the two radiotherapy planning techniques (MIT and DIT) regarding the dose distributions in the organs at risk and the 95% of the prescribed dose coverage of the target tissue. However, a significant difference for the 105% of the prescribed dose coverage, maximum dose delivered to the target tissue, and the level 2 lymph nodes dose was found, with the DIT showing higher values. Because of the good matching and no superposition observed between the treatment fields in the MIT, it was expected and confirmed that the hot and cold regions (with higher and lower doses than the prescribed dose) with the MIT are significantly fewer than that of the DIT. Therefore, to perform a better conformal radiotherapy for the patients having mastectomy, it could be recommended to use the MIT instead of the DIT and other conventional techniques.
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Neoplasias da Mama/radioterapia , Mastectomia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Parede Torácica/efeitos da radiação , Adulto , Idoso , Neoplasias da Mama/cirurgia , Simulação por Computador , Elétrons , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico , Dosagem RadioterapêuticaRESUMO
Purpose: The purpose of the study was to investigate the radiosensitization effect of radiofrequency (RF) hyperthermia in combination with PEGylated gold nanoparticles (PEG-GNPs) on MCF-7 breast cancer cells under electron beam radiotherapy (EBRT) based on the clonogenic assay. Materials and Methods: The cell death of MCF-7 breast cancer cells treated with 13.56 MHz capacitive RF hyperthermia (power: 150W) for 2, 5, 10, and 15 min combined with 6 MeV EBRT, with a dose of 2 Gy, was evaluated in the presence of 20 nm PEG-GNPs with a low nontoxic concentration (20 mg/l). All the treatment groups were incubated for 14 days. Thereafter, survival fractions and viability of the cells were calculated and analyzed against the control group. Results: The presence of PEG-GNPs inside the MCF-7 cancer cells during electron irradiation decreased cell survival significantly (16.7%) compared to irradiated cells without GNPs. Applying hyperthermia before electron irradiation with a capacitive RF system decreased cell survival by about 53.7%, while hyperthermia without irradiation did not show any significant effect on cell survival. Combining the hyperthermia with the presence of PEG-GNPs in the cells decreased the cell survival by about 67% at the electron irradiation, showing their additive radiosensitization effect. Conclusion: Low nontoxic concentration of 20 nm PEG-GNPs increases the radiosensitization effect of combining 6 MeV EBRT and RF hyperthermia on MCF-7 cancer cells. Combining hyperthermia with PEG-GNPs in electron radiotherapy could be an appropriate method for enhancing radiotherapy effectiveness on cancerous cells which can be studied on different cells and electron energies in future research.
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Neoplasias da Mama , Hipertermia Induzida , Nanopartículas Metálicas , Humanos , Feminino , Células MCF-7 , Neoplasias da Mama/terapia , Ouro/farmacologia , Elétrons , Hipertermia Induzida/métodos , Polietilenoglicóis/farmacologiaRESUMO
BACKGROUND: Low dose radiotherapy (LDRT) of whole lungs with photon beams is a novel method for treating COVID-19 pneumonia. This study aimed to estimate cancer risks induced by lung LDRT for different radiotherapy delivery techniques. METHOD: Four different radiotherapy techniques, including 3D-conformal with anterior and posterior fields (3D-CRT AP-PA), 3D-conformal with 8 coplanar fields (3D-CRT 8 fields), eight fields intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy using 2 full arcs (VMAT) were planned on the CT images of 32 COVID-19 patients with the prescribed dose of 1 Gy to the lungs. Organ average and maximum doses, and PTV dose distribution indexes were compared between different techniques. The radiation-induced cancer incidence and cancer-specific mortality, and cardiac heart disease risks were estimated for the assessed techniques. RESULTS: In IMRT and VMAT techniques, heart (mean and max), breast (mean, and max), and stomach (mean) doses and also maximum dose in the body were significantly lower than the 3D-CRT techniques. The calculated conformity indexes were similar in all the techniques. However, the homogeneity indexes were lower (i.e., better) in intensity-modulated techniques (P < 0.03) with no significant differences between IMRT and VMAT plans. Lung cancer incident risks for all the delivery techniques were similar (P > 0.4). Cancer incidence and mortality risks for organs located closer to lungs like breast and stomach were higher in 3D-CRT techniques than IMRT or VMAT techniques (excess solid tumor cancer incidence risks for a 30 years man: 1.94 ± 0.22% Vs. 1.68 ± 0.17%; and women: 6.66 ± 0.81% Vs. 4.60 ± 0.43%: cancer mortality risks for 30 years men: 1.63 ± 0.19% Vs. 1.45 ± 0.15%; and women: 3.63 ± 0.44% Vs. 2.94 ± 0.23%). CONCLUSION: All the radiotherapy techniques had low cancer risks. However, the overall estimated risks induced by IMRT and VMAT radiotherapy techniques were lower than the 3D-CRT techniques and can be used clinically in younger patients or patients having greater concerns about radiation induced cancers.
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COVID-19/radioterapia , Neoplasias Induzidas por Radiação/prevenção & controle , Planejamento da Radioterapia Assistida por Computador , Adulto , Idoso , Mama/efeitos da radiação , COVID-19/patologia , Feminino , Coração/efeitos da radiação , Fatores de Risco de Doenças Cardíacas , Humanos , Irã (Geográfico) , Pulmão/patologia , Pulmão/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Neoplasias Induzidas por Radiação/diagnóstico , Neoplasias Induzidas por Radiação/etiologia , Órgãos em Risco/efeitos da radiação , Pneumonia Viral/radioterapia , Prognóstico , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos , Medição de Risco , SARS-CoV-2RESUMO
BACKGROUND: Dose painting planning would be more complicated due to different levels of prescribed doses and more complex evaluation with conventional plan quality indices considering uniform dose prescription. Therefore, we tried to introduce new indices for evaluating the dose distribution conformity and homogeneity of treatment volumes based on the tumoral cell density and relative volumes of each lesion in prostate IMRT. METHODS: CT and MRI scans of 20 male patients having local prostate cancer were used for IMRT DP planning. Apparent diffusion coefficient (ADC) images were imported to a MATLAB program to identify lesion regions based on ADC values automatically. Regions with ADC values lower than 750 mm2/s and regions with ADC values higher than 750 and less than 1500 mm2/s were considered CTV70Gy (clinical tumor volume with 70 Gy prescribed dose), and CTV60Gy, respectively. Other regions of the prostate were considered as CTV53Gy. New plan evaluation indices based on evaluating the homogeneity (IOE(H)), and conformity (IOE(C)) were introduced, considering the relative volume of each lesion and cellular density obtained from ADC images. These indices were compared with conventional homogeneity and conformity indices and IOEs without considering cellular density. Furthermore, tumor control probability (TCP) was calculated for each patient, and the relationship of the assessed indices were evaluated with TCP values. RESULTS: IOE (H) and IOE (C) with considering cellular density had significantly lower values compared to conventional indices and IOEs without considering cellular density. (P < 0.05). TCP values had a stronger relationship with IOE(H) considering cell density (R2 = -0.415), and IOE(C) without considering cell density (R2 = 0.624). CONCLUSION: IOE plan evaluation indices proposed in this study can be used for evaluating prostate IMRT dose painting plans. We suggested to consider cell densities in the IOE(H) calculation formula and it's appropriate to calculate IOE(C) without considering cell density values.
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Próstata , Radioterapia de Intensidade Modulada , Humanos , Masculino , Próstata/diagnóstico por imagem , Radioterapia de Intensidade Modulada/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Imagem de Difusão por Ressonância MagnéticaRESUMO
Aims: This study aimed to compare the skin dose calculated by treatment planning system (TPS) and measured with thermoluminescent dosimeters (TLDs) in brachytherapy of prostatic cancer to show the skin TLD dosimetry as an appropriate quality assurance procedure for TPS dose calculations. Methods: The skin dose of 15 patients with prostatic cancer treated by high dose rate brachytherapy technique was assessed by two types of TLD dosimeters (GR-200 and TLD-100). The TLDs were placed on the patient's skin at three different points (anterior, left, and right) using five TLDs for each point. The dose values of TLDs and TPS were compared using paired t-test and the percentages of difference were reported. Results: There was a good agreement between TPS calculations and TLDs measurements for both of the GR-200 and TLD-100 dosimeters. The mean skin dose values for anterior, left, and right points were 65.06±21.88, 13.88±4.1, and 10.05±4.39 cGy, respectively, for TPS. These values were 65.70±23.2, 14.51±4.3, and 10.54±5 cGy for GR-200, and 64.22±23.5, 13.43±4.4, and 9.99±4.1 cGy for TLD-100, respectively. Conclusion: The TPS skin dose calculations in brachytherapy of prostatic cancer had a good agreement with the TLD-100 and GR-200 measurements at the three different points on patients' skin. TLD-100 had lower differences with TPS calculations compared to GR-200. Relevance for Patients: The outcome of this research shows that for people with prostatic cancer, TPS can estimate accurately the skin dose of different points including anterior, left, and right in brachytherapy technique.
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INTRODUCTION: There are various radioprotective agents with different mechanisms that help to decrease ionizing radiation side effects. The radioprotective effect of Cimetidine and IMOD was assessed individually and compared with the hybrid radioprotectors agents (HRPAs-IMOD and Cimetidine) on human lymphocyte cells. METHODS: Twenty healthy volunteers (ten men and ten women) participated in the present study. About 75 mL peripheral blood lymphocytes from each individual were collected, and they were divided into 36 groups. Briefly, the blood samples were treated with different concentrations of Cimetidine (12.6 and 25.2 µg/mL) and IMOD (0.04, 0.08, and 0.12 mg/mL), and also a combination of these agents, namely hybrid radioprotectors agents (HRPAs). Besides, the irradiated groups were exposed to 2 and 4 Gy of Co-60 gamma irradiation. The amount of cellular damage was assessed using the micronucleus assay. The repeated measurements and paired T-test statistical analysis were used to compare the micronucleus frequencies in different groups. RESULTS: The micronucleus frequencies were significantly reduced (p < 0.05) in irradiated groups when the non-toxic concentrations of Cimetidine, IMOD, and HRPAs have been used. The reduction in micronucleus frequency was obtained 5-29% for Cimetidine and 40-51% for IMOD in peripheral blood lymphocytes irradiated with 2 Gy. This reduction in 4 Gy irradiation was 8-17% for Cimetidine and 27-37% for IMOD. The HRPAs resulted in a higher radioprotective effect, in a way that they cause up to 58% and 43% micronucleus frequency reduction in 2 and 4 Gy, respectively. CONCLUSION: In conclusion, the HRPAs showed the highest level of radioprotective. In addition, IMOD was remarkably higher radioprotective than Cimetidine, which may be related to its greater non-toxic concentrations.
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Cimetidina/farmacologia , Fatores Imunológicos/farmacologia , Protetores contra Radiação/farmacologia , Estudos de Casos e Controles , Células Cultivadas , Cimetidina/administração & dosagem , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Fatores Imunológicos/administração & dosagem , Técnicas In Vitro , Testes para Micronúcleos/métodos , Protetores contra Radiação/administração & dosagemRESUMO
PURPOSE: Pneumonitis and lung fibrosis, as the most common compliances of lung irradiation, can affect the quality of life. The use of radio-protective agents can ameliorate these injuries. This study aimed to review the potential protective role of melatonin in the treatment of radiation-induced Pneumonitis and lung fibrosis. METHODS: The current systematic study was conducted based on PRISMA guidelines to identify relevant literature on " the effect of melatonin on radiation-induced pneumonitis and lung fibrosis" in the electronic databases of Web of Science, Embase, PubMed, and Scopus up to January 2021. Eighty-one articles were screened in accordance with the inclusion and exclusion criteria of the study. Finally, eight articles were included in this systematic review. RESULTS: The finding showed that the lung irradiation-induced pneumonitis and lung fibrosis. The co-treatment with melatonin could alleviate these compliances through its anti-oxidant and anti-inflammatory actions. Melatonin through upregulation of some enzymes such as catalase, superoxide dismutase, glutathione, NADPH oxidases 2 and 4, dual oxidases 1 and 2, and also downregulation of malondialdehyde reduced oxidative stress following lung radiation. Moreover, melatonin through its anti-inflammatory effects, can attenuate the increased levels of nuclear factor kappa B, tumor necrosis factor alpha, transforming growth factor beta 1, SMAD2, interleukin (IL)-4, IL-4 receptor-a1 (IL4ra1), and IL-1 beta following lung radiation. The histological damages induced by ionizing radiation were also alleviated by co-treatment with melatonin. CONCLUSION: According to the obtained results, it was found that melatonin can have anti-pneumonitis and anti-fibrotic following lung irradiation.
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Neoplasias Pulmonares/radioterapia , Pulmão/efeitos da radiação , Melatonina/farmacologia , Pneumonia/etiologia , Fibrose Pulmonar/etiologia , Lesões por Radiação/prevenção & controle , Protetores contra Radiação/farmacologia , Animais , Humanos , Pneumonia/prevenção & controle , Fibrose Pulmonar/prevenção & controleRESUMO
INTRODUCTION: The aim of this study was to investigate and compare the radio-protective effect of green tea, grape seed, and coffee bean extracts in different oral consumption methods in mice. MATERIALS AND METHODS: In this experimental-quantitative study 150 mice in 15 equally sized groups were used. For each extract, two groups received 200 mg/kg of herbal extracts' combination for 7 and 30 consecutive days before irradiation, and one group received 800 mg/kg of the extract 2 h before irradiation (3 Gy gamma-rays of Co-60). The similar groups were classified to receive a combination of the plant extracts (green tea, grape seed, and coffee bean). Irradiation without consuming plant extract (irradiated group), and a control group were also devised. Alkaline comet and micronucleus assays were used to investigate the radioprotective effect on mice blood and bone marrow cells, respectively. RESULTS: Consumption of all plant extracts significantly decreased the radiation damage to blood and bone marrow cells, compared to the irradiated group (p < 0.01), with grape seed extract showing higher protective effect. Continuous daily oral consumption (one week/month) showed a significant higher radioprotective effect compared to single consumption (p < 0.05). Continuous consumption of the combination of the extracts showed a higher radio-protection in comparison to each of the plant extracts (p < 0.03). CONCLUSIONS: The radioprotective effect of continuous consumption (for one week/month) of the plant extracts was greater than single dose. In continuous consumption protocols, we found the synergetic property and higher radioprotective effect of the plant extract combination compared to each one.
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Café/química , Raios gama , Extratos Vegetais/uso terapêutico , Lesões por Radiação/prevenção & controle , Protetores contra Radiação/uso terapêutico , Sementes/química , Chá/química , Vitis/embriologia , Administração Oral , Animais , Ensaio Cometa , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Extratos Vegetais/administração & dosagem , Protetores contra Radiação/administração & dosagemRESUMO
OBJECTIVES: Our study aimed to apply the apparent diffusion coefficient (ADC) values to quantify the differences between low- and high-grade glioma tumors. METHODS: We conducted a multicenter, retrospective study between September to December 2019. Magnetic resonance imaging (MRI) diffusion-weighted images (DWIs), and the pathologic findings of 56 patients with glioma tumors (low grade = 28 and high grade = 28) were assessed to measure the ADC values in the tumor center, tumor edema, boundary area between tumor with normal tissue, and inside the healthy hemisphere. These values were compared between the two groups, and cut-off values were calculated using the receiver operating characteristic curve. RESULTS: We saw significant differences between the mean ADC values measured in the tumor center and edema between high- and low-grade tumors (p< 0.005). The ADC values in the boundary area between tumors with normal tissue and inside healthy hemisphere did not significantly differ in the groups. The ADC values at tumor center and edema were higher than 1.12 × 10-3 mm2/s (sensitivity = 100% and specificity = 96.0%) and 1.15 × 10-3 mm2/s (sensitivity = 75.0% and specificity = 64.0%), respectively, could be classified as low-grade tumors. CONCLUSIONS: The ADC values from the MRI DWIs in the tumor center and edema could be used as an appropriate method for investigating the differences between low- and high-grade glioma tumors. The ADC values in the boundary area and healthy tissues had no diagnostic values in grading the glioma tumors.
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Measurement of background radiations (BRs) as the sources of cancer risk, is important. The aim of this study was to measure the BR, as well as its cancer risk and mortalities in Kohgiluyeh and Boyer-Ahmad province (KBAp). Indoors and outdoors BRs were measured in eight cities utilizing a Geiger-Muller detector. Five main locations (north, east, west, south, and center) were chosen for measuring outdoor and indoor BRs in each city of KBAp. The BEIR VII-Phase 2 model was used to calculate the BRs induced cancer risks and mortalities of various cancer types at different ages. The average dose rates of outdoor and indoor were 136.9⯱â¯12.5 and 149.3⯱â¯19.8 nSv.h-1, respectively. The average annual effective doses (AEDs) for adults, children, and infants were 0.17, 0.19, and 0.22 mSv.y-1 due to the outdoor, and 0.73, 0.84, and 0.94 mSv.y-1 resulting from the indoor exposure, respectively. The average lifetime risk for one year BRs induced cancers was 164.8⯱â¯15.7 and 307.1⯱â¯32.3 (in 100,000 people) for new-borns male and female, in that order. This risk decreased with age and reached 11.2⯱â¯1.6 and 13.8⯱â¯1.6 (in 100,000 people) for men and women at the age of 80, respectively. The average lifetime risk of mortality due to cancers induced by annual BRs was 70.7⯱â¯8.3 and 113.8⯱â¯10.6 (incidence probability in 100,000 people) for new-borns male and female respectively. This risk decreased with age and reached 9.8⯱â¯1.3 and 12.2⯱â¯1.3 (in 100,000 people) for men and women at the age of 80 years, respectively.
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INTRODUCTION: Ionizing radiations induce damage to the bone marrow and blood cells. The aim of this study was to investigate the radioprotective effect of sesamol oral consumption on mice bone marrow and peripheral blood cells using micronuclei and alkaline comet assay. MATERIALS AND METHODS: This experimental-quantitative study was performed on 50 mice in 5 equal groups. One group received 50 mg/kg of sesamol for 7 consecutive days and another group received 100 mg/kg of this extract 2 h before irradiation (3 Gy gamma-rays of Cobalt-60). Irradiation without consuming sesamol and sesamol without irradiation were applied in other groups. Micronucleus and alkaline comet assays were used to measure the DNA damages in bone marrow and peripheral blood cells. The data were statistically compared using one-way ANOVA, and Tukey HSD test. RESULTS: In comparison with the only-irradiated group, oral consumption of sesamol 2 h and 7 days before irradiation decreased remarkably micro-nucleated normochromatid erythrocytes (mnNCE) as 54.5% and 70.4% (P < 0.0001), and micro-nucleated nucleated polychromatid erythrocytes (mnPCE) as 49% and 66% (P < 0.001), respectively. Furthermore, the number of PCE/NCE ratio increased as 47% and 83.6% (P < 0.0001) compared to the irradiated group. The percentage of DNA in tail and apoptotic comets decreased significantly with oral consumption of sesamol (daily or single dose) compared to the irradiated group (P < 0.005). These variations were greater in 7-day continuous pre-irradiation method. CONCLUSION: Sesamol as a radioprotector can reduce the effects of gamma irradiation on mice bone marrow and blood cells. The daily oral consumption of this extract is more effective in comparison with the single consumption before irradiation.
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Benzodioxóis/administração & dosagem , Ensaio Cometa , Raios gama , Testes para Micronúcleos , Fenóis/administração & dosagem , Protetores contra Radiação/administração & dosagem , Administração Oral , Animais , Células Sanguíneas/efeitos dos fármacos , Medula Óssea/efeitos dos fármacos , CamundongosRESUMO
This study aimed to introduce a new method for eye lens thermo-luminescent dosimetry and also estimate the dose associated with induced cancer risk due to the ionizing radiation exposure received by physicians and other staff cooperating in interventional cardiology (IC) procedures. The measurements were performed with six TLDs (thermoluminescent dosimeters): four TLDs for eye lens dosimetry (2 positioned on respiratory/surgical mask under the eye region as the new method; and 2 near the outside border of the eye as the common method) and two TLDs for whole-body dosimetry. Whole-body doses were used to calculate the cancer risks induced by IC procedures. The results of the new proposed method for eye lens dosimetry were similar to common TLD positioning (mean differences <5%) and mask displacement had no significant effect on eye dose measurement in our new method. Our proposed method for eye lens dosimetry is simpler and more comfortable compared to the common method and it can be used as an alternative method without using TLD holders to monitor lens dose for IC workers wearing masks during the procedure. The estimated excess cancer incidence risk induced by IC procedures was 29.58 ± 5.71 and 46.68 ± 7.77 (per 100000 individuals) for men and women, respectively.
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INTRODUCTION: Ionizing radiations produce free radicals which are often responsible for DNA damage or cell death. Grape seed extract (GSE) is a natural compound having an antioxidant that protects DNA, lipids, and proteins from free radical damages. In this study, radioprotective effect of the GSE has been investigated in mouse bone marrow cells using micronucleus test. MATERIALS AND METHODS: Four groups of mice were investigated in this study: Mice in Group 1 were subjected to injection of distilled water with no irradiation. Mice in Group 2 were exposed to 3 Gy gamma radiation after the injection of distillated water. Mice in Group 3 were injected with 200 mg/kg of the GSE without any irradiation. In another group, mice were exposed to three gray gamma irradiation after the injection of GSE. Animals were killed, and slides were prepared from the bone marrow cells 24 h after irradiation. The slides were stained with May Grunwald-Giemsa method and analyzed microscopically. The frequency of the micronucleated polychromatic erythrocytes (MnPCEs), micronucleated normochromatic erythrocyte (MnNCEs), and polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte (PCE/PCE + NCE) ratios was calculated. RESULTS: Injection of GSE significantly decreased the frequency of MnPCEs (P < 0.0001) and MnNCEs (P < 0.05) and increased the ratio of PCE/PCE + NCE (P < 0.0001) compared to the irradiated control group. DISCUSSION AND CONCLUSIONS: GSE could reduce clastogenic and cytotoxic effects of gamma irradiation in mice bone marrow cells; therefore, it can be concluded that the GSE is a herbal compound with radioprotective effects against gamma irradiation. Free radical scavenging and the antioxidant effects of the GSE probably are responsible mechanisms for the GSE radioprotective effects.
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Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/efeitos da radiação , Raios gama , Extrato de Sementes de Uva/farmacologia , Protetores contra Radiação/farmacologia , Animais , Células da Medula Óssea/metabolismo , Eritrócitos/efeitos dos fármacos , Eritrócitos/efeitos da radiação , Raios gama/efeitos adversos , Extrato de Sementes de Uva/química , Masculino , Camundongos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Testes para Micronúcleos , Protetores contra Radiação/químicaRESUMO
This study aimed to compare and evaluated the dosimetric characteristics of esophagus, spinal cord, carotid artery, lungs, and brachial plexus in patients with breast cancer undergoing four various techniques of supraclavicular irradiation. By keeping unchanged the breast tangential radiotherapy fields, four different treatment field arrangements were created to irradiate the supraclavicular region as follows: (1) four field (4F; 1 anterior-posterior and 1 posterior-anterior), (2) six field (6F; 2 anterior-posterior and 2 posterior-anterior), (3) five field-1 (5F-1; 2 anterior-posterior and 1 posterior-anterior), and (4) five field-2 (5F-2; 1 anterior-posterior and 2 posterior-anterior). Then, the dosimetric parameters for the above-mentioned organs were evaluated. The mean dose (Dmean) of the esophagus had significant difference between 6F and 5F-2 techniques. For the spinal cord, the Dmean dosimetric parameter demonstrated significant difference between the 4F and 6F techniques, and between the 4F and 5F-1 techniques, with lower values for the 4F technique. There was no significant difference between the different irradiation techniques in all the dosimetric parameters for the carotid artery. The Dmean of the left lung significantly differed between the 4F and 5F-2 techniques, with lower values for the 5F-2 technique. Furthermore, the V20Gy dosimetric parameter had significant difference between the 4F and 6F, and also 4F and 5F-2, techniques with lower values for 5F-2. The maximum dose (Dmax) of the brachial plexus showed significant difference between the two techniques of 5F. The V45Gy dosimetric parameter of the brachial plexus revealed significant difference between the 4F and 6F techniques, and also between the 4F and 5F-1 techniques, with lower values for 5F-1. In general, these techniques had similar dosimetric results, with little differences. The dosimetric parameters for the esophagus and lung showed better results with the 5F-2 technique in comparison with other techniques. Dosimetric results for the brachial plexus and spinal cord improved with the 5F-1 and 4F techniques, respectively, against other techniques. Dose distribution for the carotid artery did not differ in the four irradiation techniques.
Assuntos
Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Neoplasias Unilaterais da Mama/radioterapia , Feminino , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Pessoa de Meia-Idade , Radiometria , Dosagem RadioterapêuticaRESUMO
Gafchromic films are utilized for two-dimensional dose distribution measurements, especially in radiotherapy. In this study, we investigated a close connection between energy and dose rate of Gafchromic EBT3 films irradiating with 6 MV and Co-60 photon beams over a broad dose range. EBT3 films were exposed to 6 MV and Co-60 photon beams using 4 and 2 Gy/min dose rates over a 10-400 cGy dose range. The films were scanned in red, green, and blue channels to obtain the optical density (OD)-dose curves. The OD-dose curves resulted from three-color scans for different photon energies and dose rates were compared by statistical independent t-test. For the radiations of Co-60 and 6 MV photon beams, the highest correlation was obtained between the 2 and 4 Gy/min dose rates with red and green channels, respectively. Moreover, the red channel had a greater OD response per dose value, following the green and blue channels. There was no significant difference between different photon energies' (Co-60 and 6 MV) and dose rates' (2 and 4 Gy/min) dependence on OD-dose response of EBT3 films over a broad domain of radiation dose, except for different photon energies in the blue channel. Our results revealed that the OD-dose response of EBT3 films is independent on photon energies (Co-60 and 6 MV) and dose rate (2 and 4 Gy/min) in the evaluated dose range (10-400 cGy). Therefore, the EBT3 films are suitable, consistent, and reliable instruments for dose measurements in radiotherapy.
RESUMO
The purpose of the data is to estimate the excessive risk of cancer due to some common radiographs in Tehran. The data were collected in 8 radiology centers in Tehran city and on 283 patients with eight radiographic views. To obtain the data, PCXMC 2.0 based on Monte Carlo calculations, has been used to calculate the effective dose of each organ, and annual effective dose. The effective dose, cumulative effective dose, number of radiographs per year and excessive cancer risk due to the type of radiographs calculated. The additional risk of lethal cancer resulting from these radiographs in the target population is about 14.81 cases of the total population of Tehran city in one year.