Showing papers in "Iranian Journal of Medical Physics in 2017"
TL;DR: There were wide variations in QC test results, perhaps mainly due to the fact that it is not an obligation to implement QC programs in Iran, and the most important problems were non-reciprocity of exposure, nonlinearity of Exposure with milliampere-second (mAs), kVp and timer inaccuracy.
Abstract: Introduction Quality control (QC) techniques are used in monitoring and maintenance of the components of an x-ray system. QC of radiology devices plays a significant role in reduction of medication dose and optimization of image quality. This study aimed to conduct QC tests on randomly selected radiology devices, installed in diagnostic imaging departments of Iran. Materials and Methods In total, quality control tests were conducted on 51 conventional radiology devices installed in 20 cities of Iran in order to assess the accuracy of peak kilovoltage (kVp), exposure time, exposure linearity and reciprocity, reproducibility of exposure and determination of half-value layer (HVL) using a calibrated Mult-O-Meter. Results In this study, 38.6% of devices had intolerable variance of kVp accuracy. The results of 34.5% of devices were out of the acceptable limits in exposure time accuracy test. In 46.7% and 53.1% of devices, variance was greater than the acceptable range for exposure linearity and exposure reciprocity, respectively. In terms of reproducibility of exposure test, the reproducibility variance and percentage of tube output variations in 19.4% of devices exceeded the limits. Moreover, the thickness of first HVL was lower than the acceptable limit in 14.7% of devices. Conclusion According to the results of this study, there were wide variations in QC test results, perhaps mainly due to the fact that it is not an obligation to implement QC programs in Iran. The most important problems were non-reciprocity of exposure, nonlinearity of exposure with milliampere-second (mAs), kVp and timer inaccuracy. Involvement of medical physicists, radiologists and radiographers in the implementation of QC programs at various stages of development, installation and use of equipment should enable the gradual improvement in equipment performance.
12 citations
TL;DR: In this paper, the concentrations of the natural radionuclides, namely 226Ra, 232Th, and 40K, were measured in the soil samples taken from different locations of Golestan, Iran.
Abstract: Introduction: Considering the risk of radiation, the measurement of the natural radiation sources seems to be necessary. In this study, the concentrations of the natural radionuclides, namely 226Ra, 232Th, and 40K, were measured in the soil samples taken from different locations of Golestan, Iran. The measurement results can also be used as a baseline to evaluate the impact of non-nuclear activities and the routine releases of nuclear installations. Materials and Methods: A total of 42 soil samples were collected. The samples were sealed for at least three weeks to ensure the secular equilibrium between 226Ra and 232Th and their respective radioactive progenies. The activity concentrations of natural radionuclides in soil samples were measured using a shielded HPGe detector. Results: The average activity concentrations of 226Ra, 232Th, and 40K were 23, 31, and 453 Bq.kg-1, respectively. To assess the radiological hazards, the Ra equivalent activity as well as the external and internal hazard indices were estimated. Radium equivalent varied within the range of 58.4-142.6 Bq.kg-1 with a mean value of 102.4 Bq.kg-1. The estimated mean values of Hex and Hin (0.28 and 0.34, respectively) in the area under investigation were lower than unity as desirable. Therefore, it did not pose any health risks to the population of the area. Conclusion: The results of this study were compared with those of other studies carried out in other countries. As the findings of the present study indicated, the health-related risks causing by the naturally accruing radionuclides was very low in the investigated area.
10 citations
TL;DR: The results of this study showed that the obtained results from MCNP-X were in high accordance with the National Institute of Standards and Technology data, and would be beneficial for use of present simulation technique and mass attenuation coefficients for medical and radiation physics applications.
Abstract: Introduction: Investigation of radiation interaction with living organs has always been a thrust area in medical and radiation physics The investigated results are being used in medical physics for developing improved and sensitive techniques and minimizing radiation exposure In this study, mass attenuation coefficients of different human organs and biological materials such as adipose, blood, bone, brain, eye lens, lung, muscle, skin, and tissue have been calculated Materials and Methods: In the present study, Monte Carlo N-Particle eXtended (MCNP-X) version 240 was used for determining mass attenuation coefficients, and the obtained results were compared with earlier investigations (using GEometry ANd Tracking [GEANT4] and FLUKA computer simulation packages) for blood, bone, lung, eye lens, adipose, tissue, muscle, brain, and skin materials at different energies Results: The results of this study showed that the obtained results from MCNP-X were in high accordance with the National Institute of Standards and Technology data Conclusion: Our findings would be beneficial for use of present simulation technique and mass attenuation coefficients for medical and radiation physics applications
10 citations
TL;DR: Najaf governorate had a lower emission rate of alpha particles as compared to other sites of the worldwide, and it could be concluded that there is no negative consequence threatening the people’s health in this regard.
Abstract: Introduction: 238U decays with alpha particles emission into 234Th and the series ends with 206Pb. The unstable nucleus loses the energy with emitting ionizing alpha particles for reaching a stable state. It is undergoing alpha decay with decay energy (4.679 MeV). Alpha particles enter the human and animal bodies through inhalation of air or ingestion of contaminated food and water. This study aimed to perform a radiological analysis on the natural alpha particle emission rates of the human teeth as the biomarkers of radiation exposure and environmental pollution. Materials and Methods: This study was conducted on 68 teeth samples of 27 males and 41 females collected from the hospitals distributed across Najaf governorate, including many districts in Iraq. Alpha particle emission rates were measured using CR-39 nuclear track detector. Results: The mean emission rate of alpha particles in the female teeth was 0.0396±0.0070 mBq cm-2, which was relatively higher than that in the male teeth (0.0390±0.0048 mBq cm-2). Nevertheless, there was no significant difference between the female and male teeth regarding the emission rate of alpha particles. Furthermore, the emission rate of alpha particles in the teeth of the samples taken from Kufa (0.0417±0.0057 mBq cm-2) was higher than those obtained from Najaf (0.0384±0.0053 mBq cm-2). Conclusion: As the findings of this study revealed, Najaf governorate had a lower emission rate of alpha particles as compared to other sites of the worldwide. Therefore, it could be concluded that there is no negative consequence threatening the people’s health in this regard.
9 citations
TL;DR: Clinical practice of using the standard HU-RED calibration curve by a 120 kVp CT acquisition technique is viable and variation in doses calculated by algorithms with various HU–relative electron density (RED) calibration curves was found to be well within 1%.
Abstract: Introduction: In radiotherapy treatment planning system (TPS), basic input is the data from computed tomography (CT) scan, which takes into account the effect of inhomogeneities in dose calculations. Measurement of CT numbers may be affected by scanner-specific parameters. Therefore, it is important to verify the effect of different CT scanning protocols on Hounsfield unit (HU) and its impact on dose calculation. This study was carried out to analyse the effect of different tube voltages on HU for various tissue substitutes in phantom and their dosimetric impact on dose calculation in TPS due to variation in HU–relative electron density (RED) calibration curves. Materials and Methods: HU for different density materials was obtained from CT images of the phantom acquired at various tube voltages. HU-RED calibration curves were drawn from CT images with various tissue substitutes acquired at different tube voltages used to quantify the error in dose calculation for different algorithms. Doses were calculated on CT images acquired at 120 kVp and by applying CT number to RED curve obtained from 80, 100, 120, and 140 kVp voltages. Results: No significant variation was observed in HU of different density materials for various kVp values. Doses calculated with applying different HU-RED calibration curves were well within 1%. Conclusion: Variation in doses calculated by algorithms with various HU-RED calibration curves was found to be well within 1%. Therefore, it can be concluded that clinical practice of using the standard HU-RED calibration curve by a 120 kVp CT acquisition technique is viable.
8 citations
TL;DR: The IMRT plans were significantly advantageous over the 3DCRT plans with some small variations in each patient, and more studies are needed for the optimization of radiobiological models for the prediction of the treatment outcomes in radiation therapy.
Abstract: Introduction: Radiobiological modeling of radiotherapy plans are used for treatment plan comparisons. The current study aimed to compare the three-dimensional conformal radiation therapy (3DCRT) and intensity-modulated radiation therapy (IMRT) plans for nasopharyngeal cancer using radiobiological modeling. Materials and Methods: This study was conducted on 10 patients with nasopharyngeal carcinoma, who were planned for 3DCRT and IMRT treatments by using the TiGRT treatment planning system. The planning target volume (PTV) doses of 70 and 72 Gy were administered for the 3DCRT and IMRT plans, respectively. The BIOLPLAN software and the Niemierko’s equivalent uniform dose (EUD) model were utilized for the estimation of tumor control probability (TCP) and normal tissue complication probability (NTCP). The NTCPs of the spinal cord, brain stem, parotid glands, middle ears, temporomandibular joints (TMJ), mandible, and thyroid were calculated by using two radiobiological models. Results: According to the results, the mean TCPs for 3DCRT and IMRT plans were 89.92%±8.92 and 94.9%±3.86, respectively, showing no statistically significant difference (P=0.08). The NTCPs of the parotid glands, thyroid gland, spinal cord, TMJ, and mandible were considerably lower in the IMRT plans, compared to those in the 3DCRT plans. On the other hand, the calculated NTCPs for the middle ears and brain stem increased for the IMRT plans, which were not statistically significant. On average, the NTCPs of the critical organs were lower based on the EUD model than the Lyman-Kutcher-Burman model. Conclusion: From the radiobiological point of view, the IMRT plans were significantly advantageous over the 3DCRT plans with some small variations in each patient. On average, the two radiobiological models generated different NTCPs depending on the studied organs. Consequently, more studies are needed for the optimization of radiobiological models for the prediction of the treatment outcomes in radiation therapy.
7 citations
TL;DR: The awareness level of the radiographers about the radiation protection principles was relatively good, however, it seems that the educationlevel of the staff should be enhanced through holding regular short-term radiation training courses.
Abstract: Introduction This study was conducted to evaluate the radiographers’ awareness of radiation protection principles in the radiology centers of the hospitals of Bandar Abbas, Iran. Materials and Methods This analytical cross-sectional study was conducted on 50 radiographers of three hospitals affiliated with Hormozgan University of Medical Sciences in 2015. The data were collected using a two-part questionnaire. The first part was related to the demographic information of the radiographers(i.e. age, gender, work experience, workplace, and passing related training courses). The second part consisted of questions related to the radiographers’ awareness in three fields of radiology physics, radiation protection, and hazards of radiation. Results According to the results of the present study, the mean total scores of the radiographers’ awareness about the radiology physics, radiation protection, and hazards of radiation was 18.41±1.14 out of 22. However, the radiographers’ awareness of the three investigated fields had no statistically significant relationships with the work experience (P=0.244) and gender (P=0.386). However, there was a significant relationship between the radiographers’ awareness about the radiation protection and their education level (P=0.034). Moreover, a significant association was found between the radiographers’ awareness and their workplace (P=0.009). Additionally, the participation in the radiation training courses was significantly correlated with the radiographers’ awareness regarding the radiation hazards (P=0.022). Conclusion According to the findings of the present study, the awareness level of the radiographers about the radiation protection principles was relatively good. However, it seems that the education level of the staff should be enhanced through holding regular short-term radiation training courses.
6 citations
TL;DR: In this paper, the authors investigated the relationship of the pulse width and intensity with the conductivity changes during reversible electroporation using simulation software and found that the tissue conductivity increased with the elevation of the electric field intensity.
Abstract: Introduction: Irreversible electroporation (IRE) is a process in which the membrane of the cancer cells are irreversibly damaged with the use of high-intensity electric pulses, which in turn leads to cell death The IRE is a non-thermal way to ablate the cancer cells This process relies on the distribution of the electric field, which affects the pulse amplitude, width, and electrical conductivity of the tissues The present study aimed to investigate the relationship of the pulse width and intensity with the conductivity changes during the IRE using simulation
Materials and Methods: For the purpose of the study, the COMSOL 5 software was utilized to predict the conductivity changes during the IRE We used 4,000 bipolar and monopolar pulses with the frequency of 5 kHz and 1 Hz, width of 100 µs, and electric fields of low and high intensity Subsequently, we built three-dimensional numerical models for the liver tissue
Results: The results of our study revealed that the conductivity of tissue increased during the application of electrical pulses Additionally, the conductivity changes increased with the elevation of the electric field intensity
Conclusion: As the finding of this study indicated, the IRE with high-frequency and low electric field intensity could change the tissue conductivity Therefore, the IRE was recommended to be applied with high frequency and low voltage
6 citations
TL;DR: An intelligent decision support system for the diagnosis of AMD fundus using retina images using convolutional neural networks is proposed, an important step toward providing a reliable tool for supervising patients.
Abstract: Introduction: Age-related macular degeneration (AMD) is one of the major causes of visual loss among the elderly. It causes degeneration of cells in the macula. Early diagnosis can be helpful in preventing blindness. Drusen are the initial symptoms of AMD. Since drusen have a wide variety, locating them in screening images is difficult and time-consuming. An automated digital fundus photography-based screening system help overcome such drawbacks. The main objective of this study was to suggest a novel method to classify AMD and normal retinal fundus images. Materials and Methods: The suggested system was developed using convolutional neural networks. Several methods were adopted for increasing data such as horizontal reflection, random crop, as well as transfer and combination of such methods. The suggested system was evaluated using images obtained from STARE database and a local dataset. Results: The local dataset contained 3195 images (2070 images of AMD suspects and 1125 images of healthy retina) and the STARE dataset comprised of 201 images (105 images of AMD suspects and 96 images of healthy retina). According to the results, the accuracies of the local and standard datasets were 0.95 and 0.81, respectively. Conclusion: Diagnosis and screening of AMD is a time-consuming task for specialists. To overcome this limitation, we attempted to design an intelligent decision support system for the diagnosis of AMD fundus using retina images. The proposed system is an important step toward providing a reliable tool for supervising patients. Early diagnosis of AMD can lead to timely access to treatment.
5 citations
TL;DR: The findings revealed the use of high kVp, automatic exposure control, correct focus image receptor distance, tight collimation and additional filter resulted in a lower ESD.
Abstract: Introduction: In digital radiography, radiographers tend to increase exposure factors to acquire an acceptable image quality thereby increasing radiation dose to patients. Regarding this, the present study aimed to re-evaluate the exposure parameters and to ascertain the entrance surface dose (ESD) and effective dose (ED) of posterior-anterior (PA) chest, abdomen, and anterior-posterior (AP) lumbosacral spine radiography.
Materials and Methods: This study was conducted on 180 physically able patients with age of 20-60 years and weight of 60-80 kg referred to Hospital Sultan Haji Ahmad Shah (HOSHAS) and Hospital Tengku Ampuan Afzan (HTAA).Image acquisition was performed using digital radiography. The ESD and ED were determined using CALDose_X 5.0 software.
Results: The ESD and ED for PA chest were 0.098 mGy and 0.012 mSv in HOSHAS, while in HTAA were 0.161 mGy and 0.021 mSv respectively. Regarding the abdomen, the ESD and ED were 2.57 mGy and 0.311 mSv in HOSHAS and 2.16 mGy and 0.262 mSv in HTAA respectively. For AP lumbosacral spine, the ESD and ED for HOSHAS were 2.65 mGy and 0.222 mSv, while in HTAA were 2.357 mGy and 0.201 mSv respectively.
Conclusion: The findings revealed the use of high kVp, automatic exposure control, correct focus image receptor distance, tight collimation and additional filter resulted in a lower ESD. The ESD and ED obtained in this study were comparable with those reported by other studies and lower than the values recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation in 2008.
5 citations
TL;DR: The average annual effective dose arising from gamma background radiation was higher than global values, and more studies are required to examine the relationship between radiation-induced effects and the natural background radiation level in Khorramabad.
Abstract: Introduction Radioactive materials naturally exist in the world. Indeed, approximately 82% of human-absorbed radiation doses, which are out of human control, arise from natural sources of radiation including cosmic, terrestrial, and exposure through inhalation or ingestion. Thus, the aim of the present study was to estimate health risk, as well as the effective and organ doses from naturally occurring background radiation in residents living in the vicinity of Khorramabad, Iran. Materials and Methods This cross-sectional study was carried out in Khorramabad, Iran. The measurements were performed using Geiger-Muller detector (RDS-110) during daylight from April to June, 2015. The natural gamma radiation measurements were made both indoor and outdoor across five regions of Khorramabad (north, south, west, east, and center). Results The estimated mean absorbed dose rate in outdoor and indoor zones were 0.09±0.024 and 0.117±0.032 mSvy-1, respectively. Additionally, the mean annual effective dose was calculated as 0.69±0.19 mSvy-1, while the estimated health risk probability was 0.0345%. Conclusion The average annual effective dose arising from gamma background radiation was higher than global values. Therefore, more studies are required to examine the relationship between radiation-induced effects and the natural background radiation level in Khorramabad.
TL;DR: In this article, the authors used the Khokhlov-Zabolotskava-Kuznetsov (KZK) nonlinear wave equation to calculate the transient temperature in liver tissue.
Abstract: Introduction High intensity focused ultrasound (HIFU) is considered a noninvasive and effective technique for tumor ablation. Frequency and acoustic power are the most effective parameters for temperature distribution and the extent of tissue damage. The aim of this study was to optimize the operating transducer parameters such as frequency and input power in order to acquire suitable temperature and thermal dose distribution in the course of a numerical assessment. Materials and Methods To model the sound propagation, the Khokhlov-Zabolotskava-Kuznetsov (KZK) nonlinear wave equation was used and simulation was carried out using MATLAB HIFU toolbox. Bioheat equation was applied to calculate the transient temperature in the liver tissue. Frequency ranges of 2, 3, 4, and 5 MHz and power levels of 50 and 100 W were applied using an extracorporeal transducer. Results Using a frequency of 2 MHz, the maximum temperatures reached 53°C and 90°C in the focal point for power levels of 50 W and 100 W, respectively. With the same powers and using a frequency of 3 MHz, the temperature reached to 71°C and 170°C, respectively. In addition, for these power levels at the frequency of 4 MHz, the temperature reached to 72°C and 145°C, respectively. However, at the 5 MHz frequency, the temperature in the focal spot was either 57°C or 79°C. Conclusion Use of frequency of 2 MHz and power of 100 W led to higher thermal dose distribution, and subsequently, reduction of the treatment duration and complications at the same exposure time in ablation of large tumors.
TL;DR: The surveyed X-ray equipment in the radiology departments of two educational hospitals in Ahvaz, Iran was safe and the radiation dose levels were within the safe recommended limits in all locations except two points due to some structural problems, which were recognized and would be corrected as soon as possible.
Abstract: Introduction: The ionizing radiation is increasingly applied in various fields for industrial and medical purposes due to its benefits. The aim of this study was to measure the radiation levels in six radiology departments of two educational hospitals in Ahvaz, Iran. Materials and Methods: The radiation levels were measured at six locations of six radiology departments, including behind the patient observation window, staff rest room, office, patient waiting room, behind the door of the X-ray room, and outdoor. These measurements were carried out while the X-ray equipment was in on and off status, using the halogen-quenched Geiger-Mueller counter. Results: According to the results, the range of radiation levels inside the radiology departments at X-ray units with on/off status were0.36±0.12 to 0.09±0.02 µSv/h and 0.13±0.02 to 0.09±0.03 µSv/h, respectively. Furthermore, significant differences were observed between the indoor and outdoor radiation levels in all locations. Conclusion: As the findings indicated, the surveyed X-ray equipment in the radiology departments of two educational hospitals was safe. The radiation dose levels were within the safe recommended limits in all locations except two points due to some structural problems, which were recognized and would be corrected as soon as possible.
TL;DR: The status and trends of doses showed that radiation protection conditions were adequate, and all the workers received doses below the annual dose limit.
Abstract: Introduction: Assessment of occupational exposure to external radiation and the analysis of associated trends are imperative to observe changes that have taken place over time due to regulatory operations or technological advancements. Herein, we describe the occupational radiation exposure to workers employed in Nuclear Medicine (NM), Radiotherapy (RT), and Diagnostic Radiology (DR) departments at the Institute of Radiotherapy and Nuclear Medicine, Peshawar, Pakistan, and to evaluate the related trends during 2009-2016. Materials and Methods: A retrospective analysis of the dose records of 4320 film dosimeters was performed during 2009-2016. The analyzed quantities included annual collective effective dose, annual average effective dose, distribution of workers, and their annual average effective doses in various effective dose intervals, as well as the maximum and minimum annual individual effective doses. Results: The annual average effective doses in RT, NM, and DR were within the ranges of 1.07-1.45, 1.25-1.55, and 1.03-1.60 mSv, respectively. The majority (90%) of the workers received effective doses in the interval of 1-4.99 mSv, while 10% of the workers received doses within the range of the minimum detectable level-0.99 mSv. The minimum and maximum annual individual effective doses were 0.30 mSv and 3.96 mSv as recorded in RT and NM, respectively. The annual average effective doses measured for NM, RT, and DR were 1.39, 1.23, and 1.30 mSv, respectively. These values are comparable with the worldwide annual average effective doses. Conclusion: All the workers received doses below the annual dose limit. The status and trends of doses showed that radiation protection conditions were adequate.
TL;DR: Thermography is a useful method for initial varicocele screening and can be applied as a supplement to other diagnostic techniques due to its low cost and lack of radiation exposure.
Abstract: Introduction: A varicocele is the abnormal dilation and tortuosity of venous plexus above the testicles. The pattern of abnormal heat distribution in the scrotum can be detected through thermal imaging, which is a distant, non-contact, and non-invasive method. The aim of the present study is to detect and grade varicocele. Materials and Methods: This study was conducted on 50 patients with high probability of varicocele, who referred to a hospital affiliated to the AJA University of Medical Sciences, Tehran, Iran. The evaluation procedure included thermal imaging, clinical diagnosis, and ultrasound test. The gold standard method was based on ultrasound examination. The thermal imaging was performed using a non-contact infrared camera. Results: This paper presented two methods for diagnosing and grading varicocele. The first method was based on the patterns and models of thermal asymmetry in the testicles (including three asymmetric and symmetric patterns). The second method was based on the temperature differences. The obtained results demonstrated that the use of temperature differences in the diagnosis of varicocele was better than the other proposed method. In addition, a temperature difference of 0.5°C in the pampiniform venous plexus was an important indicator for the diagnosis of varicocele using thermal imaging. The accuracy of thermography in grading varicocele was 76%. Conclusion: According to the results of the study, thermography is a useful method for initial varicocele screening and can be applied as a supplement to other diagnostic techniques due to its low cost and lack of radiation exposure. Thermography was concluded to be a precise technique for the diagnosis of varicocele; however, its capability to determine the varicocele grading was comparatively low.
TL;DR: In this paper, the shielding properties of 21 galena concretes containing seven borated minerals with three mixing patterns were evaluated using MCNP4C Monte Carlo code and the attenuation of the gamma radiation was computed under the conditions of narrow and beam geometries.
Abstract: Introduction: The heavyweight concretes have been widely used for constructing medical or industrial radiation facilities with photon sources. Materials and Methods: In this study, heavy concretes containing galena (PbS) and several borated minerals are proposed as suitable materials against photons. The shielding properties of 21 galena concretes containing seven borated minerals with three mixing patterns were evaluated using MCNP4C Monte Carlo code. The attenuation of the gamma radiation is computed under the conditions of narrow and beam geometries. The x-ray sources with 40, 60, 90, and 120 kVp and gamma rays of 99mTc, 131I, 137Cs, and 511 keV annihilation photons were considered. The photon flux values and the x-ray spectrum after applying all the concretes were compared to the ordinary ones. Regarding the results, more photon attenuations obtained by using high density concretes simulation in comparison to ordinary concrete. Results: The results revealed that the concretes containing orthopinokiolite as the borated material made by the third mixing pattern, had the most photon attenuation. According to the results, the shielding properties of the concretes containing different borated minerals were alike against high photon energies, whereas in low energy photons the attenuation depended on the type of borated mineral used in the concretes. Conclusion: The high-density heavy-weighted concretes could be effectively used as multi-purpose shield for radiotherapy rooms and nuclear reactors due to the borated minerals.
TL;DR: The instrumental neutron activation analysis (INAA) was employed to measure the trace elements in 11 commonly food spices consumed in Tehran, Iran, and the concentrations of K and Na in the black pepper, garlic, and ginger were significantly higher than the values reported in other countries.
Abstract: Introduction There is a growing interest in determining the concentration of various elements in food spices. In the present study, the instrumental neutron activation analysis (INAA) was employed to measure the trace elements in 11 commonly food spices consumed in Tehran, Iran. Materials and Methods The levels of K, Mn, Na, Cl, V, Br, Al, and As were determined and their effects on human health were discussed. The results were compared with the values reported in the literature. The accuracy and precision of the analytical procedure was estimated by analyzing the Lichen (IAEA-336) reference material. Results The concentrations of the measured elements in the spices were 3850-29157, 10-335, 153-2849, 186-3063, 0.2-2.8, 2.1-58.7, and 72-2102 ppm for K, Mn, Na, Cl, V, Br, and Al, respectively. As was only detected in thyme (0.8 ppm) and plantain (0.42 ppm). Conclusion As the findings of the present study indicated, the concentrations of K and Na in the black pepper, garlic, and ginger were significantly higher than the values reported in other countries. The Mn levels in the black pepper and garlic consumed in Tehran were comparable with those in Poland. Furthermore, the concentration of As in these spices were lower than the maximum permissible limit.
TL;DR: The obtained findings showed that radiotherapy is compatible with silicone gel prosthesis, and silicon breast prosthesis has no clinicallysignificant effect on photon dose distribution in breast radiotherapy.
Abstract: Introduction: Siliconeprosthetic implants are commonlyutilizedfor tissue replacement and breast augmentation after mastectomy. On the other hand, some patients require adjuvant radiotherapy in order to preventlocal-regional recurrence and increment ofthe overall survival. In case of recurrence, the radiation oncologist might have to irradiate the prosthesis.The aim of this study was to evaluate the effect of silicone prosthesis on photon dose distribution in breast radiotherapy. Materials and Methods: The experimental dosimetry was performed using theprosthetic breast phantom and the female-equivalent mathematical chest phantom. A Computerized Tomographybased treatment planning was performedusing a phantom and by CorePlan Treatment Planning System (TPS). For measuring the absorbed dose, thermoluminescent dosimeter(TLD) chips (GR-207A) were used. Multiple irradiations were completed for all the TLD positions, and the dose absorbed by the TLDs was read by a lighttelemetry (LTM) reader. Results: Statistical comparisons were performed between the absorbed dosesassessed by the TLDs and the TPS calculations forthe same sites. Our initial resultsdemonstratedanacceptable agreement (P=0.064) between the treatment planning data and the measurements. The mean difference between the TPS and TLD resultswas 1.99%.The obtained findings showed that radiotherapy is compatible withsilicone gel prosthesis. Conclusion: It could be concludedthat the siliconbreast prosthesis has no clinicallysignificant effectondistribution of a 6 MV photon beam for reconstructed breasts.
TL;DR: In this article, a thyroid protocol was used to acquire planar images of the spheres A, B, and C (16 mm, 12 mm, and 11 mm in diameter, respectively) whilst filled with a targeted activity concentration of technetium-99m.
Abstract: Introduction: The limited spatial resolution of the gamma camera hinders the absolute quantification of planar images of small structures. The imaged structures are affected by partial volume effects (PVEs), which can spread activity and lead to underestimation of the regional distribution. The use of optimum planar parameters reduces the impact of the limited spatial resolution of the gamma camera and the statistical noise inherent to low photon count, thus improving quantification. In this study, we aimed to determine the optimum planar imaging parameters for small structures. Materials and Methods: A thyroid protocol was used to acquire planar images of the spheres A, B, and C (16 mm, 12 mm, and 11 mm in diameter, respectively) whilst filled with a targeted activity concentration of technetium-99m. One sphere was mounted at the centre of the Jaszczak Phantom and the other two adjacent to its walls using capillary stems fitted on the spheres. The phantom was filled with distilled water. The targeted activity concentrations used were 74 kBq/mL, 100 kBq/mL, 150 kBq/mL, and 300 kBq/mL. Images of the same count per pixel were acquired on 64 64, 128 128, 256 256, 512 512, and 1024 1024 pixels using a vertical detector mounted 5 cm above the phantom. All the images were quantified using ImageJ software, version 1.48a, Java 1.70_51 [64-bit]. Results: The optimum planar imaging parameters established were a matrix size of 128 128 pixels and technetium-99m solution of activity concentration of 300 kBq/ml. Conclusion: The use of optimal imaging parameters reduces the impact of PVEs, leading to improved quantitative accuracy.
TL;DR: The study shows that the exposure levels in business facilities within the CFTZ were higher than the background radiation level, and the effective doses were not uniform for the different categories.
Abstract: Introduction Exposure to chronic levels of ionizing radiation could be detrimental to health even at very low doses. Calabar free trade zone (CFTZ) was established to promote export business in Nigeria and it is yet to produce exposure data of the Zone. Materials and Methods The Zone was divided into three categories depending on the type of business. Category A had facilities with manufacturing businesses, Category B was service providers while Category C was oil and gas businesses. Exposure levels within the CFTZ were measured with exposure meter and results obtained were converted to annual effective dose in mSv/yr. The evaluated doses were used to estimate health risks to workers in the Zone in terms of lifetime cancer incidence and mortality for persons aged between 18 – 65 years using the conversion factors in BEIR VII. Results Category B facilities had dose values between 0.21 – 0.31 mSv/yr followed by Category A with dose values between 0.23 – 0.35 mSv/yr. Category C facilities had the highest dose values between 0.33 – 0.40 mSv/yr. The evaluated cancer incidence and mortality rates were generally less than 2 persons in 1,000 persons for both male and female workers. Conclusion The study shows that the exposure levels in business facilities within the CFTZ were higher than the background radiation level. The effective doses were not uniform for the different categories. The estimated cancer incidence and mortality were low, and simple linear equations were generated to relate cancer incidence to mortality.
TL;DR: This preliminary study was conducted to provide a classification method for analyzing the ESS spectra and found that this method can be helpful for classification of melanoma and normal spectra.
Abstract: Introduction: There is a strong need for developing clinical technologies and instruments for prompt tissue assessment in a variety of oncological applications as smart methods. Elastic scattering spectroscopy (ESS) is a real-time, noninvasive, point-measurement, optical diagnostic technique for malignancy detection through changes at cellular and subcellular levels, especially important in early diagnosis of invasive skin cancer, melanoma. In fact, this preliminary study was conducted to provide a classification method for analyzing the ESS spectra. Elastic scattering spectra related to the normal skin and melanoma lesions, which were already confirmed pathologically, were provided as input from an ESS database. Materials and Methods: A program was developed in MATLAB based on singular value decomposition and K-means algorithm for classification. Results: Accuracy and sensitivity of the proposed classifying method for normal and melanoma spectra were 87.5% and 80%, respectively. Conclusion: This method can be helpful for classification of melanoma and normal spectra. However, a large body of data and modifications are required to achieve better sensitivity for clinical applications.
TL;DR: In this paper, the accuracy levels of Lagrange, Newton backward interpolation, and linear interpolation methods in estimating the output factors for square fields used in linear accelerator for 6 MV photons at various depths.
Abstract: Introduction: To estimate the accuracy levels of Lagrange, Newton backward interpolation, and linear interpolation methods in estimating the output factors for square fields used in linear accelerator for 6 MV photons at various depths. Materials and Methods: Ionization measurements were carried out in radiation field analyzer in linear accelerator for 6 MV beams at the depths of 5 and 10 cm by 0.6 cc Farmer-type ionisation chamber. Dosimetry was performed by ion collection method with 0.5 cm2 interval for square fields from 4 × 4 cm2 to 40 × 40 cm2 field sizes. The measured output factor values for 10 square field sizes with equal interval were taken for interpolating the intermediate square field size values. The Lagrange and Newton backward methods were used for predicting the intermediate output factors. Results: The percentage of deviation from the measured value was estimated for all the three methods. The calculated output factor values of the two proposed methods were compared with the standard linear interpolation method used in routine clinical practice. It was observed that the Lagrange and Newton backward methods were not significantly different from the measured value (P=0.77). The linear interpolation values were significantly different from the measured value (p <0.01). Conclusion: It is recommended to use the Lagrange and Newton backward interpolation methods to estimate the intermediate output factors to increase accuracy in treatment delivery. The routine linear interpolation method can be applied only for small intervals. This proposed interpolation method is highly associated with the measured values in all the interval levels.
TL;DR: The convolution algorithm gives slightly better dosimetric results in breast cancer treatment, compared to the fast superposition and superposition algorithms.
Abstract: Introduction: Single isocentre half-beam block (HBB) technique permits the avoidance of hot and cold spots. This technique is very useful in sparing the underlying ipsilateral lung and heart, if the left breast is treated. The major advantage of this technique is that it facilitates the complete sparing of both contralateral breast and lung. Regarding this, the present study aimed to analyse the dosimetric results obtained from the HBB technique in the treatment of breast cancer using three different algorithms. Materials and Methods: For the purpose of the study, a total dose of 5000 cGy was prescribed to the planning target volume (PTV) in 25 fractions per fraction daily, five days a week. The PTV was derived by using 4-7 mm isotropic expansion of the clinical target volume (CTV) clipping 1-3 mm from the patient’s surface in the breast-conserving cases. Three plans were created for each patient using three different algorithms, including convolution, fast superposition, and superposition with the same parameters. Results: The mean doses of PTV-breast and CTV-supraclavicular fossa (SCF) were tabulated and analysed. In the PTV-breast, the maximum and minimum mean doses were 5428.8 and 4930.2 cGy, which were observed in the fast superposition and convolution algorithms, respectively. In the CTV-SCF, the maximum and minimum mean doses were 5428.8 and 5126.8 cGy, respectively, detected in only fast superposition algorithm. Conclusion: As the findings of the present study indicated, the convolution algorithm gives slightly better dosimetric results in breast cancer treatment, compared to the fast superposition and superposition algorithms. Therefore, it is prudent to apply the HBB technique with convolution algorithm using the Elekta XiO planning system in the treatment of breast cancer including supraclavicular lymph node metastasis.
TL;DR: The findings of this quality control audit for radiography and fluoroscopy devices owned by private sector in Syria illustrated that most of the considered diagnostic X-ray devices had acceptable performance and few of them need to be recalibrated for some parameters.
Abstract: Introduction: Extensive use of diagnostic radiology is the largest contributor to total population radiation doses. Thus, appropriate equipment and safe practice are necessary for good-quality images with optimal doses. This study aimed to perform quality control (QC) audit for radiography and fluoroscopy devices owned by private sector in Syria (2005-2013) to verify compliance of performance of X-ray machines with the regulatory requirements stipulated by the national regulatory body. Materials and Methods: In this study, QC audit included 487 X-ray diagnostic machines, (363 radiography and 124 fluoroscopy devices), installed in 306 medical diagnostic radiology centers in 14 provinces in Syria. We employed an X-ray beam analyzer device (NERO model 8000, Victoreen, USA), which was tested and calibrated at the National Secondary Standard Dosimetry Laboratory traceable to the IAEA Network of Secondary Standard Dosimetry Laboratories. Standard QC tool kits were used to evaluate tube and generator of the X-ray machines, which constituted potential (kVp), timer accuracy, radiation output consistency, tube filtration, small and large focal spot sizes, X-ray beam collimation and alignment, as well as high- and low-resolution and entrance surface dose in fluoroscopy. Results: According to our results, most of the assessed operating parameters were in compliance with the standards stipulated by the National Regulatory Authority. In cases of noncompliance for the assessed parameters, maximum value (28.77%) pertained to accuracy of kVp calibration for radiography units, while the lowest value (2.42%) belonged to entrance surface dose in fluoroscopy systems. Conclusion: Effective QC program in diagnostic radiology leads to obtaining information regarding quality of radiology devices used for medical diagnosis and minimizing the doses received by patients and medical personnel. The findings of this QC program, as the main part of QA program, illustrated that most of the considered diagnostic X-ray devices had acceptable performance and few of them need to be recalibrated for some parameters.
TL;DR: By investigating the effect of current density components on cellular excitability, significant individual differences in the level of excitability were detected and consideration of the real geometry in computational modeling is vital.
Abstract: Introduction: The response variability between subjects, which is one of the fundamental challenges facing transcranial direct current stimulation (tDCS), can be investigated by understanding how the current is distributed through the brain This understanding can be obtained by means of computational methods utilizing finite element (FE) models Materials and Methods: In this study, the effect of realistic geometry and white matter anisotropy on the head electrical current density intensity (CDI) distribution was measured using a magnetic resonance imaging (MRI)-derived FE model at the whole brain, below electrodes, and cellular levels Results: The results revealed that on average, the real geometry changes the CDI in gray matter and the WM by 29% and 55%, respectively In addition, WM anisotropy led to an 8% and 36% change of CDI across GM and WM, respectively The results indicated that for this electrode configuration, the maximum CDI occurs not below the electrode, but somewhere between the electrodes, and its locus varies greatly between individuals In addition, by investigating the effect of current density components on cellular excitability, significant individual differences in the level of excitability were detected Conclusion: Accordingly, consideration of the real geometry in computational modeling is vital In addition, WM anisotropy does not significantly influence the CDI on the gray matter surface, however, it alters the CDI inside the brain; therefore, it can be taken into account, especially, when stimulation of brain’s internal regions is proposed Finally, to predict the outcome result of tDCS, the examination of its effect at the cellular level is of great importance
TL;DR: The average patient dose and cancer risk estimates in both CA and PTCA were consistent with the reference levels, however, in agreement with other interventional procedures, dose levels in the interventional cardiology are influenced by staff and clinical protocols, as well as the type of equipment.
Abstract: Introduction: Coronary angiography is the most common angiographic procedure for diagnosis and treatment of the heart diseases. Herein, we aimed to evaluate the entrance surface dose (ESD), dose area product (DAP), as well as cancer risk in interventional cardiology procedures. Materials and Methods: This study was conducted during July-December 2015 at Shahid Madani Heart Center in Khorramabad, Iran. A total of 225 adult patients including 122 females and 103 males regardless of the risk factors for coronary diseases were participated. Of them, 199 and 26 patients underwent diagnostic coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA), respectively. Each patient underwent CA or PTCA separately. All the procedures were carried out using Siemens angiography system with the pulsed fluoroscopy of 10-30 pulses/s and cine frame rate of 15 frames/s. DAP, ESD, fluoroscopy time (FT), as well as the number of sequences and frames per sequence were collected for each 199 CA and 26 PTCA procedures. Results: The median values of DAP were 19.77±14.88 and 57.11±33.36 Gy.cm2 in CA and PTCA, respectively. In addition, the median values of ESD were 323.12±245.39 and 1145.22±594.42 mGy in CA and PTCA, respectively. FTs were 114.59±74.33 s in CA and 424.15±292.93 s in PTCA. Conclusion: The average patient dose and cancer risk estimates in both CA and PTCA were consistent with the reference levels. However, in agreement with other interventional procedures, dose levels in the interventional cardiology are influenced by staff and clinical protocols, as well as the type of equipment.Â
TL;DR: The FIF plan significantly reduced the dose volume of the left lung and heart in post-mastectomy radiotherapy compared to the TWB plan, and is recommended for this purpose.
Abstract: Introduction: In this study, dose distribution of the chest wall in post-mastectomy breast cancer patients was evaluated and compared in the tangential wedged beam (TWB) and field-in-field (FIF) plans. Materials and Methods: Thirty-six patients with left-sided breast cancer were enrolled in this study. The FIF and TWB plans were generated for each patient to compare dosimetric parameters of the chest wall. The maximum dose (Dmax), homogeneity index (HI), conformity index (CI), and uniformity index (UI) were defined and used for comparison of the dosimetric parameters of the planning target volume (PTV) in both FIF and TWB plans. The percentage of volumes receiving at least 10, 20, 30, and 40 Gy of the left lung and 5, 10, 20, 25 and 30 Gy of the heart were used to compare the dosimetric results of the organs at risk. Statistical analysis was performed using SPSS, version 20. Results: The FIF plan had significantly lower HI (P=0.000) than the TWB plan, indicating that the FIF plan was better than the TWB plan in PTV. The V40lung (15.36±4.35 vs. 18.37±4.42) and V30heart (8.15±3.75 vs. 10.94±3.94; P=0.000) were significantly lower in the FIF plan than in the TWB plan. In addition, the monitor unit (MU) was significantly lower in the FIF plan than in the TWB plan (227.76 vs. 323.59; P=0.000). Conclusion: The FIF plan significantly reduced the dose volume of the left lung and heart in post-mastectomy radiotherapy compared to the TWB plan. Therefore, the FIF plan is recommended for this purpose.
TL;DR: Results suggested that application of N-acetylcysteine for mice before irradiation protected them from the lethal effects of whole-body irradiation, and lack of effectiveness of treatment with NAC after lethal dose was revealed.
Abstract: Introduction
It has long been known that ionizing radiation can lead to detrimental effects in normal cells. In this light, Radioprotective chemicals have been used to decrease morbidity or mortality caused by ionizing irradiation. This study aimed to evaluate the radio-protective effect of N-acetylcysteineagainst radiation-induced mortality in male mice.
Materials and Methods
52 healthy male mice were divided into four groups including NAC before irradiation (1), irradiation (2), NAC after irradiation (3) NAC before irradiation (4) and control. Three groups were treated orally with 100 mg/ kg of NAC. Gamma irradiation was performed at 8 Gy using a Co-60 machine. Kaplan-Meier method and the log-rank test were performed, using SPSS version 16. The significance level was considered to be 0.05.
Results
The statistical analysis revealed a significant difference between the test and control groups (P<0.05). The percentage of survival after 30 days was 46.2% for the irradiation group (1). In addition, the percentage of decreased lifespan was calculated at 5.90%, 23.60% and 17.93% for the first-third groups, respectively.
Conclusion
Results revealed lack of effectiveness of treatment with NAC after lethal dose. These results suggested that application of NAC for mice before irradiation protected them from the lethal effects of whole-body irradiation.
TL;DR: The findings revealed that the active species of plasma can lead to cell death and mutagenesis effects of APPJ might be the reason of microorganism cell death after the treatment in addition to other destructive effects ofAPPJ on macromolecules.
Abstract: Introduction The aim of this study was toinvestigate the sterilization potential of atmospheric pressure plasma jet (APPJ) and interactions of this technology with double-stranded DNA using the polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP) techniques. Materials and Methods The plasma jet was produced through a high voltage sinusoidal power supplyusing a mixture of argon and oxygen gases with theflow rate of 1 L/min. Escherichia coli cells and double-stranded DNA (dsDNA) fragments were amplified by T7 universal primer through the PCR technique and treated with argon/oxygen APPJ at different exposure times. The data were analyzed by the agarose and polyacrylamide gel electrophoresis, SSCP and renewed PCR techniques. Results According to the results of the study, the APPJ could serve as an effective instrument for sterilization at > 30 sec discharge. The destruction of DNA was detectable by different techniques after 120 sec from APPJ discharge. Conclusion Our findings revealed that the active species of plasma can lead to cell death. These species may break or nick the dsDNA, exchange DNA nucleotides, and lead to transition and transversion mutations. These mutagenesis effects of APPJ might be the reason of microorganism cell death after the treatment in addition to other destructive effects of APPJ on macromolecules.
TL;DR: The results showed that changes in volumes of the bladder and rectum alter their received inter-factional mean doses during a radiotherapy course, which is recommended for more accurate IGRT treatment.
Abstract: Introduction: The aim of this retrospective study was to evaluate the variations in delivered dose to the bladder, rectum, and femoral heads of prostate cancer patients during a course of treatment by image-guided radiation therapy (IGRT). Materials and Methods: Overall, 15 patients with prostate cancer were selected and. Each week, for each patient five consecutive cone beam computed tomography (CBCT) images were taken after bony anatomy alignment by using two orthogonal radiographic images, as well as CBCT images. Dose distributions and dose volume histograms (DVH) for all the original and CBCT plans were obtained. Maximum, as well as mean doses and volumes of the bladder, rectum, and both femoral heads were recorded for each CBCT plan and compared with the original CT plan. For all the studied body parts, the differences in DVH between CBCT plans and original CT plan were calculated and compared. Results: Considering all the 75 CBCT images for the 15 patients, average of changes in mean doses and volumes were 17.8%, 41.8%, 7.1%, and 36.8% for the bladder and rectum, respectively. There was a significant (P<0.05) negative correlation between mean bladder dose and volume, while a weak and positive correlation was found between mean dose and volume of rectum in our patients. Conclusion: Our results showed that changes in volumes of the bladder and rectum alter their received inter-factional mean doses. Further attention to the volume variations of the bladder and rectum during a radiotherapy course is recommended for more accurate IGRT treatment.