Farahnaz Azarakhsh, Vahid Changizi,
Volume 10, Issue 3 (7-2016)
Abstract
Background and Aim: Brain tumors have remained as a significant cause of morbidity and mortality and are often refractory to treatment. The grading of brain tumor has an important implication in clinical management. Currently, magnetic resonance spectroscopy (MRS) is an important dimension in evaluating metabolites and grading brain tumors. The aim of this study is to evaluate metabolites in brain tumors and grading brain gliomas using HMRS (proton magnetic resonance spectroscopy).
Materials and Methods: Studies were performed using single voxel MRS, at a field strength of 3Tesla and pulse sequence using point resolved single volume spectroscopy (PRESS) with repetition time (TR) 1000-6000ms and echo time (TE) 36-136ms, and distinguished metabolites including Choline (Cho), Creatin (Cr), and N-acetyl aspartate (NAA) were detected.
Results: Thirty-seven cases (17 males and 20 females) had data which passed quality control. The patients’ age ranged from 7 to 81 years with a mean of 41.46±2.78. MRS data were processed using SYNGO software in terms of mean spectra and metabolite concentrations which were compared using minitab and SPSS. Significant differences were found in concentrations of key metabolites, and Cho/NAA and Cho/Cr ratios using t-test with a significance level (α≤0.05). In the assessment of age rate and tumor grading, the malignancies of brain tumors did not correlate with patients’ age and sex.
Conclusion: MRS can detect subtle differences between low-grade brain tumors in children and should form part of the clinical assessment of these tumors.
Mohammad Rasoul Tohidniya, Fatemeh Amiri, Karim Khoshgard, Zeinab Hormozi Moghadam,
Volume 10, Issue 6 (3-2017)
Abstract
Background and Aim: More than 80% of patients need to take x-rays during their diagnosis and treatment stages. Due to the biological effects of ionizing radiation, observance of radiation protection principles are necessary. The observance of radiation protection principles in intensive care units at Imam Reza hospital of Kermanshah in 2014 was evaluated in this study.
Materials and Methods: In this cross-sectional study which was performed by census method, performance of 38 radiographers working in target center was investigated regarding the following of the principles of radiation protection in respect of patients, nurses, radiographers, and other clients in intensive care units. Data collection tool included a questionnaire and a checklist of 31 principles of radiation protection.
Results: The overall level of observance of radiation protection principles in intensive care units was at an appropriate level (94.7%) in 36 radiographies. The highest and lowest levels of principle observance of radiographers were in respect to themselves (94.7%) and nurses in the intensive care units and other clients (26.3%), respectively.
Conclusion: According to results in this study, radiation protection principles observance by radiographers during portable radiography examinations respect of themselves is appropriate but respect of other nurses is not satisfactory. It seems that it can be improved to 100% of the optimum level by equipping intensive care units to protective equipment, setting some obligations to use them, and controlling and continuous monitoring of protective measures of radiographers.
Arezoo Imani, Fereidoun Mianji , Vahid Changizi, Seyyed Hossein Mousavie Anijdan , Reza Paydar,
Volume 11, Issue 3 (9-2017)
Abstract
Background and Aim: Estimation of radon density in underground centers is very important. Considering the use of high-energy medical accelerators, radiotherapy departments are usually located in underground floors. The aim of this study was to evaluate staff exposure to radon gas in these centers in Tehran in 2015-2016.
Materials and Methods: This is a descriptive, cross-sectional survey. In radiotherapy centers of Tehran, 32 radon gas diffusion chamber detectors were installed for a period of 3 months. After collecting the detectors, radon gas concentrations were calculated. The annual effective dose of personnel was evaluated using staff’s working hours per week.
Results: The minimum and maximum concentrations recorded in this study during one year were 22.14 and 398.52 Bq/m3, respectively, with an average of 87.01 ± 80.68 Bq/m3. Also, radiotherapy personnel’s annual effective dose was 0.34 ± 0.43 mSv per year with the minimum and maximum amounts of 0.02 and 2.35 mSv per year, respectively.
Conclusion: The results indicate that radon level in radiotherapy centers and also that the annual effective dose of personnel in these centers are permissible, and no special action is needed. However, if more attention is paid to certain factors such as air-conditioning, the amount of the gas can even be brought to less than this limit.
Vahid Changizi, Fereshteh Mohammadi , Ebrahiminia Ali,
Volume 11, Issue 5 (1-2018)
Abstract
Background and Aim: CT scan as a medical imaging modality delivers high radiation dose to the patients. Since eye and thyroid are two radiosensitive organs in this study, those effective doses were evaluated in brain CT scan. Using TLD as dosimeter.
Materials and Methods: This cross-sectional study was carried out in three selective hospitals in Rasht in September and October in year 2016.TLD was used as personal dosimeter. To measure the effective dose, TLDs were put on the patient’s eyes and thyroid and the mean effective dose was evaluated in brain CT scan. Results were analytical using SPSS software and Anova (P<0.05).
Results: The mean effective doses of eyes and thyroid in three hospitals with codes of H1, H2 and H3 were obtained as 2.66±2.04 mSv and 0.03±0.009 mSv, 1.80±1.11 mSv and 0.03±0.02 mSv, 1.94±0.95 mSv, 0.04±0.01 mSv, respectively. We found significant differences between effective doses of the eyes and thyroid in the three hospitals (p<0.05). Despite the difference in effective doses between right and left sides of eyes and thyroid, we didn't find any other significant differences.
Conclusion: The most important factor affecting patient radiation dose is the way CT scan examination is performed.
Vahid Changizi, Hossein Sadeghi, Maryam Alizadeh, Atefeh Aghaei, Mohsen Yazdanmehr,
Volume 12, Issue 3 (9-2018)
Abstract
Background and Aim: Today, OSL (Optically Stimulated Luminescence) dosimetry system based on optical stimulation, includes systems that can meet many requirements for radiation protection in the field of medicine and space. The Calcium Sulfide (CaS) is one of the earth's alkaline sulfide materials which can be used as a detector in this system. In this research, some of the dosimetry properties of CaS doped with Cerium, (Ce), and Samarium, (Sm) elements were investigated as OSL dosimeter sensor.
Materials and Methods: First, attenuation of x-rays through the sensors were analyzed and the absorbed dose rate was evaluated using MCNP code. After calcium sulfide tablets were fabricated and their concentration optimized, the maximum waiting time prior to readout was obtained. In addition, the repeatability and linear response of the detector were determined as a function of CaS concentration.
Results: Eight minutes after radiation exposure of detectors, the detection output signals became stable. This stability was monitored for at least 30 minutes after irradiation. The repeatability in measurements was observed within the dose ranges of 100 to 860 mGy. The dosimeter response was observed linear over this dose ranges.
Conclusion: According to the above-observed results and statistical evaluations, one can conclude that the CaS:Ce,Sm crystal is a proper sensor for OSL dosimeter systems in medicine and space studies.
Vahid Changizi, Fereidoun Mianji, Fereshteh Ghaderbeygizad, Fereshteh Mohammadi,
Volume 12, Issue 5 (1-2019)
Abstract
Background and Aim: Coronary angiography (CA) is a diagnostic and therapeutic procedure for cardiac complexity, that has a high dose and high fluoroscopy time. The effective dose of eye lens as a radiosensitive organ in long-term exposure to CA must be evaluated.
Materials and Methods: A cross-sectional study was performed with Siemens under-bed machine in Imam Hossein Hospital of Mehran, Ilam Province of Iran, in January and February 2016. In this study, TLD was used as personal dosimeter. To measure the effective doses, TLD was put on the external side of cardiologists’ eyes under lead glasses. Data were analyzed by spss22 at a significant level (p<0.05).
Results: The mean fluoroscopy time in the radial route was 3.17±2.11 and in the femoral route was 12.65±6.97 minutes (p=0.003). The mean effective doses of cardiologists’ right and left eyes in radial and femoral angiography were 0.003, 0.005 (p=0.02) and 0.008, 0.011 (p=0.748), respectively. The mean effective dose of eye lens in the use of radial route was obtained less than that of femoral route. The mean effective doses in right and left eyes were not significantly different in the use of radial and femoral routes.
Conclusion: Fluoroscopy time and the distance of source are the main factors of more radiation on cardiologists.
Vahid Changizi, Mohammad Reza Zare, Sahel Kasiri,
Volume 13, Issue 5 (1-2020)
Abstract
Background and Aim: Due to the presence of ionizing radiation sources in the environment and their potential to enter the food chain, the natural radiation in the rice product of Mahmoud Abadu residents of this area should be evaluated.
Materials and Methods: Using standard sampling methods, the number of sampling points and locations (about 10 points) was determined. After recording the geographical location of the sites, 2 kg of soil and 2 kg of rice were removed and 20 samples were coded. 950 g of soil and rice were milled and transferred to standard Marinelli dishes with 50 mesh. The samples were completely sealed and after about one month, they were visualized with ultra-pure germanium detectors (HPGe). Subsequently, specific radionuclide radiosensitivity in soil and rice soil samples, radionuclide transfer factors from soil to rice, annual effective dose and risk of cancer due to rice consumption were measured.
Results: Effective total dose of nuclei studied in #value, lifetime cancer risk of U238 from #value to 0.00019, Ra226 from #value to 0.00008, U235 # value, Th232 from #value to 0.00027, K40 From 0.00014 to 0.00082 and finally for zero cesium.
Conclusion: There is no harmful effect on the people of the region regarding the radionuclides of rice.
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Volume 14, Issue 3 (7-2020)
Abstract
Background and Aim: Due to the increasing number of radiographic tests, TLD dosimeters can be used to measure the effective dose of critical organs in various radiographic tests. In this research, the progression of analogue to digital radiology devices, which facilitates and accelerates the performance of radiographs, especially emergency patients, was investigated, and then the effective dose of critical organs in digital radiographic devices was calculated using a thermoluminescence dosimeter.
Materials and Methods: In this cross-sectional study 29 thermoluminescence GR-200 dosimeters(LiF: Mg, Cu, P) were used first, the TLDs were calibrated by the Atomic Energy Organization of Tehran Protection Center, then using TLDs, equivalent doses were used in radiographic tests and finally, the effective dose of critical organs was calculated.
Results: Data were analyzed using Anova in SPSS software. The mean effective doses of critical organs were 0/034±0/0015 mSv for eyes(in skull radiography), 0/0063±0/0004 for thyroid(in cervical radiography), 0/0067±0/0009 for breast(in lung radiography) and 0/2010±0/0652 for ovarian(in abdominal radiography). We found significant differences between effective doses of thyroid and ovaries in common position(Postero Anterior)(p˂0.05). We found non-significant differences between effective doses of the eyes and breast in common position(AntroPosterior)(p˃0.05).
Conclusion: According to the results of this study, the effective dose of the patient in radiographic exames depends on the thickness of the target organ and the patient's position, which has a significant effect on the dose of radiation absorbed by the patient.
Zahra Danaei, Elahe Jazayeri Gharehbagh, Seyed Mahdi Hosseini Pooya, Samaneh Baradaran,
Volume 14, Issue 5 (1-2021)
Abstract
Background and Aim: In angiography, the lens of the eye may be exposed to radiation and cause cataracts. In Iran, at present, only a single film dosimeter is used under the lead-apron to evaluate individual doses. The aim of this study was to investigate the status of occupational radiation as well as the validity of measuring the dose of the whole body of individuals and eye lenses using a single film dosimeter.
Materials and Methods: In this study, the dose of the whole body and eye lenses were measured using a combination of film and thermoluminescence dosimeters for 35 employees of the angiography departments in three selected hospitals under the auspices of Tehran University of Medical Sciences(TUMS). To measure the eye lens dose, three thermoluminescence dosimeter pellets were used on the forehead, and left and right eyes; and to measure the whole body dose using the two-dosimetry method, a TLD card mounted on the chest and on the lead apron and a film dosimeter on the chest and under the lead apron were used.
Results: The angiography personnel's monthly dose mean of the eye lenses and the whole body were approximately 240.6±6.4 μSv and 120.3±3.3 μSv,
respectively(the corresponding amount for the annual dose is less than the levels recommended by international authorities). In addition, the dose ratio of film badge to whole body and eye lens was 0.35 and 0.51, with correlation coefficients of 0.97 and 0.5, respectively. Also, the ratio of eye lens dose to depth dose(TLD) on the lead apron was 1.18 with a correlation coefficient of 0.79.
Conclusion: Using a single film dosimter under the lead apron to estimate the dose of the whole body is almost accurate but this dosimeter alone is not suitable for the assessment of the lens dose of the eye; it is necessary to use an individual dosimeter on the lead apron.
Mona Sarhadi, Mohammad Amin Shayegan,
Volume 15, Issue 1 (3-2021)
Abstract
Background and Aim: For effective treatment of Alzheimer's disease (AD), it is important to accurately diagnosis of AD and its earlier stage, Mild Cognitive Impairment (MCI). One of the most important approaches of early detection of AD is to measure atrophy, which uses various kinds of brain scans, such as MRI. The main objective of the current research was to provide a computerized diagnostic system for early diagnosis of AD, using leraning machine algorithms, to help physicians. The proposed system diagnoses AD by examining the hippocampal atrophy of brain MRI images and increases the accuracy of the diagnosis.
Materials and Methods: In this study, hippocampus was segmented from the other parts of the brain by using active contour and convolutional neural network and then, three groups of “Normal Controls: NC”, AD and MCI were classified by using the SVM classifier.
Results: The proposed method has succeeded in classifying AD against NC with 98.77%, 98.74% and 97.96% in average for accuracy, sensitivity and specificity, respectively. Also in classification of MCI against NC, the mean accuracy, sensitivity and specificity of 96.14%, 96.23% and 88.21% were achieved, respectively. Compared with the nearest rival method, the proposed method showed improvement accuracy and sensitivity of classification AD from NC with 1.64% and 2.81% respectively. Also, in classification of MCI from NC it showed improvement for accuracy with 8.9% and sensitivity with 2.16%, respectively. Improving in results were due to the use of a modified ACM segmentation algorithm, the use of a combination of features extracted from hippocampal images and features already created by the ImageNet network, the removal of inappropriate features from the feature vector, and the use of deep Inception v3 network.
Concolusion: Based on the results, the combination of polygon surrounding the hippocampus features and deep network features can be useful for detection of AD and MCI.
Vahid Changizi, Maryam Mohammadi, Samaneh Baradaran, Mehran Taheri,
Volume 15, Issue 4 (10-2021)
Abstract
Background and Aim: On panoramic radiographs, sensitive organs, including the thyroid, are exposed to radiation. Thyroid cancer is one of the most common cancers in Iran. That is why, in this study the effective dose and risk of thyroid cancer were estimated on panoramic radiography.
Materials and Methods: Seventy GR200 thermoluminescence (TLD) dosimeters were used to estimate the absorbed dose of thyroid. The dosimeters were calibrated and placed on the patients’ necks during panoramic radiography. After dosimeters were read, the mean absorbed dose and effective thyroid dose were calculated in three groups with different radiation conditions. Lifetime Attributable Risk (LAR) of thyroid cancer was estimated using the model presented in the BEIR VII report. GraphPad Prism statistical software was used to analyze the data.
Results: The mean absorbed dose of thyroid lobes in groups M, L, XL (According to mandibular size) was estimated to be 0.116±0.01, 0.123±0.04 and 0.03±0.134 mg, respectively. The right thyroid lobe in group XL with absorption dose of 0.143±0.05 mg and the left lobe in group M with absorption dose of 0.106±0.03 mg had the highest and the lowest absorption doses, respectively. The difference between the absorbed doses of the right and left thyroid lobes in any of the three groups was not statistically significant. Thyroid absorption doses in these three groups were not statistically significant. The highest risk of thyroid cancer in the age range of 15-60 years was related to the age of 15, which was estimated to be 0.238 in women and 0.042 in men per 100,000 people.
Conclusion: In lower ages and among women, the risk of thyroid cancer is higher than that of men. Also, due to the impossibility of limiting thyroid radiation in panoramic radiography using lead thyroid collar that causes metal artifacts, we should reduce the number of panoramic radiographs as much as possible, especially at lower ages.
Hassan Zarghani, Masoud Jabbari, Sajjad Pandesh,
Volume 18, Issue 1 (3-2024)
Abstract
Background and Aim: X-ray radiation, besides its useful applications in the diagnosis and treatment of diseases, also has harmful effects. With the increasing demand for various radiographs and X-ray imaging, radiation protection for radiographers is of particular importance. In this regard, a study was conducted to examine the level of awareness, attitude, and performance of radiographers in Iran with regards to the effects of ionizing radiation and protective methods against them.
Materials and Methods: In this descriptive-analytical study, based on a census, the awareness, attitude, and performance of radiographers in 52 cities in Iran were examined by using a questionnaire. Data from 847 radiographers were collected. Finally, the data were analyzed using t-test and analysis of variance through SPSS statistical software.
Results: Out of the total distributed questionnaires (748 items), 531 questionnaires were completely filled by radiation workers. In the present study, 46% were male and 53% were female, with average scores related to the awareness, attitude, and performance of radiographers in the field of radiation protection being 59.9, 69.4, and 43.54, respectively. There was no statistically significant difference (P<0.05) between the awareness levels of individuals who had undergone refresher training (24.3%) and those who had not. Radiographers’ knowledge of specialized information such as the principle of As Low as Reasonably Available (ALARA) (68.5%), Bucky factor (65.5%), and heel effect (61%), alongside the relationship between source-to-skin distance and radiation intensity (71%), was at a moderate level.
Conclusion: The poor performance of radiologists in this study is not solely attributed to functional deficiencies but sometimes also involves the institutionalization of incorrect principles. These weaknesses and shortcomings are undoubtedly the result of inadequate supervision and erroneous modeling over a long period. If not addressed, they will undoubtedly have irreparable destructive consequences in the future, especially with the increasing advancement of diagnostic radiology methods.
