نشریه سنجش و ایمنی پرتو
سال یازدهم شماره 4 (پیاپی 44، زمستان 1401)

SPECT-CT is used to study the physiology of Cardiac in two stages, means, stress and rest. In the stress stage, a 20 mCi of 99mTc-MIBI is injected to the patient and scan is done. If the patient is a pregnant woman who is in a special condition, Imaging is performed at rest two hours after stress by re-injecting 20 mCi of 99mTc-MIBI radiopharmaceutical. Due to the fact that the developing fetus inside the uterus, it is sensitive to any radiation, so it is important to find how much radiation dose is absorbed by the fetus and it is the goal of this research. To achieve this goal, MCNPX code and ORNL phantom, were used to simulate the fetus, uterus and other tissues inside the maternal in three periods of pregnancy, means, three, six and nine months by using spherical lines. The radiopharmaceutical is distributed throughout the body via the cardiac pumping. Therefore all organs become a radioactive source. 21 organs close to the fetus were considered as volumetric sources and the absorbed dose of the fetus was calculated in three periods of pregnancies. The absorbed dose of fetus in the stress stage in three, six and nine months of pregnancy are 1.26 × 10-2, 2.9 × 10-3, 2.83 × 10-4 mGy respectively. The absorbed doses in the rest mode without urination in the mentioned periods are 2.52 × 10-2, 5.79 × 10-3, 5.68 × 10-4 mGy respectively. Furthermore the absorbed doses in the rest mode with two times urination and considering a biological half-life of 3 hours, and 25% of the injected radiopharmaceutical comes out by urinary excretion, were found 1.89 × 10-2, 4.35 × 10-3, 4.25 × 10-4 mGy in the mentioned periods, respectively. Therefore, to reduce the absorbed dose of fetal and the potential risks, it is strongly recommended to the patient to drink fluids as much as possible in the two hours interval between the scans.

Proton therapy is one of the prostate cancer treatments. Bragg peak in proton depth-dose curve is the most important characteristic of this method. It causes the most amount deposition of energy in the tumor. Prostate is not a fixed organ and has involuntary movement in the range of 1-7mm due to bloating of the gastrointestinal tract in body, so this movement results in uncertainty in absorbed dose of particle. In this research absorbed dose are calculated regarding prostate movement using FLUKA code which works with Monte Carlo method. First, the phantom used is simulated. Regarding depth of 15cm of prostate in body the needed energy to form Bragg peak in tumor was calculated 148 MeV with 0.02% precision. Total Absorbed dose for one proton particle is 7.2 nGy when prostate was considered fixed in coordinate center .it was shown that 99.9% of total absorbed dose which is deposited in prostate and does not damage other tissues. The reason for this is the presence of Bragg Peak, which is all the energy absorbed in this area. with moving prostate for 7mm in perpendicular proton beam direction, the total dose absorbed by the prostate is reduced by 2.2%, also for moving prostate in line with proton beam, the total dose absorbed by the prostate is reduced by 6.66%.

Staff training is one of the priorities of any organization. Therefore, reviewing and knowing the results and efficiency of staff training is a requirement of the training process. The purpose of this study is to evaluate the effectiveness of radiation protection training courses for medical and industrial centers It was November of 1399.

Method of research: 

The present study is descriptive-survey in terms of method and applied in terms of research purpose. For this purpose, 76 participants in the program have been studied. Data related to the evaluation of the effectiveness of the training course were held and also the components of the Kirk Patrick evaluation model were collected. Descriptive statistics and inferential statistics including t-tests were used to analyze the data.

The results show that radiation protection courses held by the Radiation Research Center of Shiraz University have been effective in both levels of reaction and learning and also these courses have been able to provide employee satisfaction.

Finally, it can be said that the participants in the training courses in general, have evaluated the effectiveness of the training courses at a desirable level and the mentioned trainings have increased knowledge and skills.

Nowadays, in one hand, the potential clinical application of helium ion beams is being discussed in the literature. In other hand, MR-guided radiotherapy has been welcomed by the radiotherapy oncology community so far. The idea of ​​combining an MRI system with a helium-ion beam delivery gantry has challenges, one of which is the dose changes in the patient's body that occur due to the deviation of the initial beam under a magnetic field. In order to quantitatively evaluate these dose changes, in this study, variation in the depth- and transverse dose profile curves inside a water phantom at therapeutic energies under magnetic fields of 0.35, 1.5 and 3 T were calculated using the FLUKA Monte Carlo code. The percentage of dose fluctuation in the direction of the central axis due to the application of magnetic field at minimum, medium and maximum energies was calculated and it was shown that the maximum dose changes occur at 220.5 MeV / n energy and at a depth of 30.9 cm phantom. Also, the maximum longitudinal retraction and deflection of helium beams in the presence of 3 Tesla magnetic field and at 220 MeV energy were 5.2 mm and 4.7 mm, respectively. To evaluate the accuracy of the simulations, depth-dose curves of helium ion beams in a water phantom were compared with the experimental data without the magnetic field influence. The maximum difference between the simulated and the measured values was 0.962 mm which is less than the permissible limit for predicting the Bragg peak of the ion beam for clinical dosimetry purposes.

Alpha particles emit electromagnetic radiation as they stop in the environment due to ionization and exciting atoms. The energy spectrum and intensity of radiation depends on the material and the percentage of elements in the target and its thickness. By placing layers of different metals and materials and changing their thickness in front of the entrance window of CsI (Tl) scintillator and interpreting the change in intensity in different detector channels, a suitable method for detecting alpha particles is introduced. In this research, the alpha particles of 241Am source with an energy of 5.48 MeV are irradiated into layers of aluminum, copper, iron, steel, paper, radiological films, lead and plastic with different thicknesses and was studied the count  variation of CsI (Tl) scintillation channels. By interpreting the results, was obtained the channels that show the maximum intensity of photons due alpha particles stopping in target. According to the observation of X-ray channels related to alpha particle stopping in target, a method for radon detection has also been introduced. In this method, hot spring water is poured into a plastic container with a thin layer of iron embedded at the end. First the background spectrum was measured. Then the water inside the container is stirred and the difference in spectrum is measured. The most suitable channel for measuring radon is channel 57. According to the obtained results, the relationship between radon concentration and counting rate in this channel has been extracted.

Humans are exposed to external and internal radiation from various radiation sources such as cosmic radiation, ambient radiation, Radon and radiation therapy devices annually. The permissible annual dose limit set by the ICRU report for ordinary people is 0.05 Sv. The amount of environmental radiation depends on the type of soil, building materials, granite and the surrounding environment, which can be reduced by changing these materials to reduce the risks of environmental radiation. Unfortunately, there are villages in Kerman that are located on a bed of radioactive granite. In this study, the amount of hazards caused by these stones for the residents of Mani, Khanaman and Dehsiahn villages has been investigated. The research results show that the activity of  the 232Th, 238U, 40K and 137Cs radioactive elements and the quantities of Raeq, Dr, Dout, Din, Dtot, Hex, Hin, Iy, ELCR of these three villages are higher than The permissible values ​​are announced by the ICRU.

Radioisotopes were usually produced by reactors and cyclotron and linear accelerators. In this research, we try to use the Monte Carlo method using MCNP code to simulate neutron activation by the neutron source of Kerman and to investigate the interest of the produced radioisotopes. For this purpose, X-ray powder diffraction is used to detect the constituent elements of these materials. Neutron activation requires a source to bombard the sample, which produces the radioisotope of the elements. Each radioisotope emits a specific spectrum that can be used to determine the concentration of elements in it. The result of the study using the MCNP code shows that it is possible to produce a radioactive source by Kerman neutron source. Radioisotope 36Cl has the highest production interest among the materials irradiated by Kerman neutron source. Therefore, Kerman neutron source can be used to produce suitable radioisotopes for nuclear laboratories.

The International Space Station (ISS) is constantly exposed to space radiation. Therefore, it is important to study the effects of radiation on the body. In this research, the spallation of the body of the Destiny module of the ISS by the cosmic oxygen source is simulated using the MCNP code in accordance with the Monte Carlo method. The abundance of oxygen in interstellar gas is commonly used as a metal detector in galaxies. For irregular galaxies, the amount of oxygen is related to the total mass of the galaxy, meaning that the higher the total mass, the higher the heavy element content. Spallation also refers to nuclear reactions that occur when high-energy particles interact with an atomic nucleus. The MCNP code is a Monte Carlo nanoparticle code that can be used to transmit neutrons, photons, electrons, and … . The body of the ISS space station is always under cosmic radiation. High-flux cosmic rays and particles can affect humans and space components. These effects can cause spallation and changing the  material or stopping charged particles and producing secondary radiation. Measuring the abundance of cosmic radionuclides with long half-lives in the atmosphere and terrestrial reserves is a very important tool for studying atmospheric processes and  the interactions between different reservoirs. The purpose of this study is to calculate the cosmic oxygen spring splitting using the MCNP code. The results of this study show that important radioisotopes such as ، ،، and   are produced by spallation of the space station body  with oxygen ions.

Recently, Slot scanning imaging system is a new imaging system. This imaging system is designed to sweep the object in a linear manner with a narrow beam. The aim of this study was to investigate the effect of filter thickness on the contrast of images obtained from simulation of slot scanning imaging system using GATE code. First, the effect of additional aluminum filter thickness from unfiltered to 4 mm aluminum on the energy spectrum of X-rays emitted in the imaging system was investigated. Then, the filtering effect was evaluated by designing a contrast test phantom that includes filters with different copper thicknesses to determine the contrast to noise ratio (CNR).The results showed that by increasing the thickness of the filter on the beam, the beam will be softer and its low energy and useless beams will be removed. Also, due to the fact that by adding a filter with a thickness of 2 mm, the contrast reduction to noise is less than 10%, so the optimal filter thickness for the  slot scanning imaging system was 2 mm aluminum filter to not lose image quality. The results of this study can be used to evaluate the patient dose in incisional scanning imaging.

External human radiation due to radiation from natural resources is much more than artificial sources. In this study, the amount of outdoor background radiation was measured in different parts of Rasht city and the dose rate was calculated.RDS-110 was used to measure background radiation in this cross-sectional study.To measure background radiation at the same height, a metal base with a height of one meter was used and the device was placed on it.Dose rate equivalent to background radiation for outdoor space was measured in nine areas (north, south, east, west, center, northwest, northeast, southwest and southeast) and for each point twelve stages were measured at 5 minutes intervals.The average dose rate equivalent to background radiation and its standard deviation in the outdoor is  79/88±5/74nSv/h which is 34% higher than the global average of the equivalent dose rate.Also, the annual effective outdoor dose rate in Rasht city is 0/098±0/007mSv/y, which shows a higher amount compared to the global average of effective outdoor dose rate.

In the previous studies, a new type of gamma radiation dosimeter based on polymer/carbon nanostructures nanocomposite has been presented by the authors and also the dosimetric properties for this type of dosimeter have been investigated. In this experimental work, the electrical resistance of 0.28wt% Polystyrene/Multi-Walled Carbon Nanotube (PS/MWCNT) nanocomposite was measured at the temperature range of 25-75 °C. The work of a calorimeter is based on increasing the temperature of the sensitive volume due to irradiation. Results showed that with increasing the temperature, the electrical resistance of the nanocomposite was increased linearly and due to calorimetric relationships could be used as a calorimeter in the radiation processing region to measure the absorbed dose up to about 50 kGy.

In this study, calculations related to the mass attenuation coefficient (µ/ρ) of Polyethylene/Bismuth Oxide composite (HDPE-Bi2O3) for different weight percentages of Bi2O3 in the polymer matrix, namely 0 wt%, 1 wt%, 2 wt%, 3 wt%, 5 wt% and 8 wt% for photons with 59 keV energy that can be used in dental radiography centers were simulated using the MCNP code and results were compared with XCOM data. The simulation results of the mass attenuation coefficient of the composite in different weight fractions via the methods of MCNP and XCOM at 59 keV showed a good agreement with each other. The results of this study showed that the Polyethylene/Bismuth Oxide composite material in optimal weight fraction and thickness can be used as a radiation shield in dental radiography centers.

Detection and dosimetry of ionizing radiation are important and fundamental issues in the nuclear industry. In this study, calculations related to the optimal thickness of a new beta detector for 90Sr source based on Polycarbonate/Bismuth oxide composite material (PC-Bi2O3) for different weight percentages of bismuth oxide fillers in polymer matrix, namely 0 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% were carried out using the ESTAR program. Results showed that the weight percentage of bismuth oxide particles was effective in determining the range and stopping power of the electrons in the composite detector. Finally, for 90Sr, using the evaluation of beta particles range in the aforementioned composite material, the optimal thickness for this detector was calculated.

One of the key factors in the assessment of the quality assurance in advanced radiotherapy treatments such as IMRT and VMAT is obtaining different types of dose leakages related to the MLCs used in these techniques. In this study, different dose leakage parameters from TiGRT Dynamic MLC, which was externally added to the lower part of the collimator system of Siemens linear accelerator, were measured using different dosimeters (diode dosimeter and radiochromic film) and compared with Monte Carlo simulation results. Measurement indices include radiation beam leakage from the air gap between the leaves (inter-leaf leakage), the amount of X-ray passage through individual leaves (intra-leaf transmission), average leakage and leakage related to the air gap of the leaves in the completely closed radiation field (abutting air gap leakage) were at  6-MV energy. In measuring the various leakage dose indices from TiGRT Dynamic MLC, a good agreement was observed between the measured data and the simulation results. According to the TG-50 protocol, the average interleaf leakage and interleaf leakage should be less than 2%; and the results of our study showed that the leakage parameters obtained from this type of MLC agree with the universal protocols.

The Tc-99m DMSA is one of the most widely used radiopharmaceuticals in nuclear medicine. This radiopharmaceutical is used to study the location, size, shape, and function of the kidneys. In this paper, the absorbed doses of different organs and the effective dose after injection of this radiopharmaceutical have been calculated using the MIRD method. For this purpose, the specific absorbed fractions have been obtained for adult phantom of revised ORNL phantom series using Monte Carlo simulations, and then the S values ​​for the Tc-99m radionuclide have been calculated. Finally, the absorbed doses of different organs have been calculated using the biokinetic data of ICRP 53 for Tc-99m DMSA. The results show that the kidneys, bladder wall, spleen, and adrenal glands receive the highest absorbed dose after injection of Tc-99m DMSA. Also, the effective dose per unit activity administered is estimated to be 1.60E-02 mSv/MBq.

Dose evaluation is one of the main steps in cancer treatment. In process of treatment it is always a concern to conentrate the absorbed dose on the effected area and reduce the abosorbed dose on healthy organs. Brachytherapy is One of the major cancer treatment methods which uses various radionucleids as source. Although the most common source in this method is Ir-192 but Cs-137 has also an extensive use too. In this study the Absorbed dose in the superficial brachytherapy for treatment of keloids has been evaluated.    Cs-137 was chosen as source and  MCNP4C code was employed for the simulation.

the absorbed dose due to ionizing radiation is a function of three parameters: 1- Time 2- Source 3- Shielding. shielding materials -as any other material- activate when they are exposed to irradiation. The aim of this study is to calculate the attenuation coefficient and investigate shielding properties of different concrete compounds with various aggregates. After that the required time for achieving IAEA anounced clearance levels for these compounds was calculated by ORIGEN-S code.Cs, Co and Eu are important radionucleids in term of determine the required time for achieving clearance levels.

In this paper, the effect of gamma radiation on the properties of bipolar and MOSFET transistors and ordinary Schottky diodes for dosimetry is investigated and compared. For gamma irradiation, a Gamasel device containing 60 cobalt springs with an activity of 5770 curries located in the Atomic Energy Organization of Tehran was used. Experiments were performed to irradiate parts under doses of 2, 4, 8, 16 and 32 kg. The results showed that gamma radiation in this dose range significantly affects the parameters of electronic components. The dose change curve relative to the flow is linear. Individual dosimeters can be divided into active and inactive categories. Individual passive dosimeters use detectors that are capable of storing recorded data for a long time. Nuclear and germline solid state detectors are the most important options used, passive dosimeters . With the growth and development of semiconductor materials technology, especially silicon, silicon-based individual active gamma dosimeters have been well developed and they have been used instead of inactive gamma film films. Transistors and silicon diodes are the best tools for use as detectors in the individual gamma active dosimeter due to their small volume, low weight, low operating voltage, good energy resolution, simple operation and ease of transport .

In this research, Increasing the dose of cancer cells compared to normal cells is done by adding gold nanoparticles to the tumor.Gold nanoparticles due to biocompatibility and low toxicity have been considered in recent years. Results of studies in this field represents an increase in radiation dose to the tumor with gold nanoparticles is reached.

The most common method External radiation therapy uses beams of photons, protons, neutrons and heavy ions. The use of proton beams to treat cancer due to the Bragg peak in the target volume, causing less damage to surrounding tissue, and this is one of the benefits of this treatment.

Using ionizing radiation in medicine, industry and research is developing rapidly. The principles of radiation protection guarantee the health of workers, public and the environment. Therefore, the development of guides and training of workers is the most important requirements and programs of regulatory bodies. Despite the requirement of radiation center to comply with regulations, there have been occurrence of radiation accidents. Industrial radiography, as one of the most hazardous radiation activities, which uses high activity sources, has already been exposed to radiation accidents. In this study, 43 cases of recorded radiation accidents related to industrial radiography have been investigated in terms of the effective factor in the accident and secondary factors that have interfered in the progression of the accident have also been considered. The classification of accidents in terms of the main factor shows that non-compliance with work processes has the highest number of accidents. Inadequate regulatory control and deliberate misconduct at a considerable distance are next. Examination of the main causes of radiation accidents in industrial radiography shows that proper training of radiologists and application of instructions can be effective in controlling the occurrence of radiation accidents.

At proton therapy due to protons interaction with devices located in front of the beam and used for modulation and also with patient body atoms, secondary particles are produced such as neutrons. Until now, many research studies have been done working on the topics of radiation protection and keeping patient body safe against secondary neutrons produced in front of the therapeutic beam, but there are rare studies on neutrons produced inside patient body. In this research, we have quantitatively investigated the presence and neutrons flux inside tumor volume and surrounding soft tissues, while their measurements is impossible experimentally using neutrons detectors. To do this investigation, a simulation environment has been used by means of Monte Carlo FLUKA code. A spherical tumor with 2.5 cm radius has been assumed inside a cubic phantom assigned with soft tissue equivalent matter. In this work, proton as therapeutic beam has been simulated with the parameters used clinically while there are uniform dose distribution onto tumor volume at all dimensions. Neuron flux between tumor and normal tissues borders and also the number of total neutrons exited from patient body have been calculated. In general, energy deposition of neutrons produced inside patient body is very low in comparison with energy deposition of protons as therapeutic beam and this is due to low effective atomic number of soft tissue equivalent phantom.

With the widespread use of radiation sources and radioactive materials in medicine, industry and agriculture, the study of the attenuation and absorption of X-rays and gamma rays and shielding against them has become an essential and important branch in the field of radiation protection. In this research, linear and mass attenuation coefficients, effective atomic numbers and effective electron density of barium-bismuth-borosilicate glasses at energies of 662, 1173 and 1332 KeV are calculated using the MCNP4C code and XCOM program. Then obtained results are compared with available experimental data. Barium-bismuth-borosilicate glasses showed very good shielding properties against gamma rays.

In this project, feasibility of direct production of praseodymium-140 radioisotope by direct method using 140Ce(p,n)140Pr reaction excitation function obtained from the calculation code TALYS-1.8 has been investigated. On the other hand, due to the short half-life 3.39m, this radioisotope can be produced in small portable cyclotron to medical centers. Using the excitation function, the optimal energy range for the proton projectile to achieve the maximum product cross-section 140Pr and the minimum isotopic and non-isotopic contamination caused by other decay channels during the reaction, it is determined. Finally, the theoretical production yield is compared with the simulated production yield, which are directly and indirectly derived from the MCNPX code.

Introducion: 

The new 2019 coronavirus in most patients manifests as an uncomplicated respiratory disease and in some patients it can lead to pulmonary complications, septic shock and in a few cases lead to the death of the patient. Given that the patientchr('39')s first encounter with the emergency department is the hospital triage unit, it is important to quickly identify and isolate patients suspected of having a coronavirus. In order to evaluate the effect of respiratory triage on referral of corona positive patients to the medical imaging department, in this study, the rate of positive CT scans performed in the first and fourth peaks (with triage) and a two-month period without Widespread (no triage) was performed.

The present study was a cross-sectional descriptive study that was performed in three stages in Baharloo Hospital. Patients first underwent respiratory triage in the two peak periods, but triage was removed in the period without outbreaks. CT scans taken by a radiologist were performed to check for the presence or absence of corona based on the degree of lung involvement. The obtained data were analyzed by SPSS 22 software through descriptive statistics and t-test.

In all three stages, the percentage of people without pulmonary involvement was higher than those with pulmonary involvement, so more care should be taken when requesting a CT scan by a physician. In addition, in the presence of triage, negative CT scans in individuals are reduced. When we encounter the pandemic and epidemic conditions and the high level of radiation and no pulmonary involvement in some cases, CT scan should not be used as the only initial diagnostic test for screening for patients with coronavirus.

Patient dose is relatively low in radiography but because of numerous uses in diagnosis, it can cause a large amount of cumulative dose and therefore it be needed to use techniques to reduce patient dose. Digital radiography based on quantum efficiency and capability of image processing presents new chances for image optimization. However, the transmission from film-screen radiography to digital radiography has been done without dose optimization techniques and new optimization techniques are needed to be achieved to the ALARA conditions. In this study studies with the subject of optimization of digital radiography has been reviewed.

X-ray is one of the medical imaging methods, which helps physicians correctly diagnose diseases. Improper adjustment of X-ray tube parameters, different types of artifacts, and noise are factors affecting the quality of radiographic images. In some cases, poor quality of the images may lead to re-imaging, which increases the patient's dose. Today, artificial intelligence has made significant progress in various fields. Deep learning is one of the branches of artificial intelligence, which is widely used in medical imaging. In this article, the generative adversarial network is used as one of the most powerful available neural network models for resolution improvement, noise, and artifact reduction of chest X-rays. The values of RMSE, PSNR, and SSIM are calculated for 150 images with an average of 4.66, 34.92, and 0.923, respectively. These results show that trained networks have a high ability to improve the resolution of chest X-rays and make them more diagnostically valuable. Also, in cases where the image quality is low for any reason, there will be no need for re-imaging, and the patient will not receive the extra dose resulting from the re-imaging.

Physical inspection methods are not limited to metal detectors. Today, whole-body or part-body scanners are widely used in some countries. Body scanners are systems used to control people suspected of carrying weapons, explosives and narcotics embedded in body cavities at airports, prisons or other sensitive security and economic centers. At present, about 20 Soter-RS body scanners have been used in the country. The amount of dose received by the person being scanned with these devices is one of the most important aspects of their safety that is used in categorizing the device as well as determining the number of scans allowed for each person during a year. Of course, the justification for using such systems depends on the laws and regulations of each country. Studies and evaluations of body scanners in operation in the country show that the devices are in a limited-use range (Limited-use) but still with a limited number of scans recommended in the standard ANSI-43.17, the dose received by these people is less than the dose limit and the limited dose. Monitoring and evaluations show that the limit of the number of scans in accordance with the dose applied to the devices used in the country has been observed.

In this study, the 199Au nanoparticles production parameters have been investigated by a two-part study.The first part is about the indirect method for production of non-carrier-added (NCA) 199Au radionuclide which was investigated both theoretically and experimentally. We applied MCNPX-2.6 code, TALYS-1.9, and ALICE code, aiming to simulate the reactor core of Tehran Research Reactor (TRR) and determining the activity of 199Au by MCNPX code using cross-sections calculated by TALYS-1.9 and specifying the production yield of 199Au. Also, the excitation function of 199Au was calculated via  reaction by TALYS-1.9 and ALICE/ASH-0.1 codes. As the corresponding experimental approach, we worked on the reactor production of 199Au by utilizing  thermal neutron flux through irradiation of natural Pt target for a specified irradiation time of 21 hours and 10 minutes in TRR. Regarding our facilities for evaluating the production yield, two samples of 11 mg and 15.5 mg natural Pt targets were bombarded in TRR. Because the natural Pt target, consists of five different stable isotopes (192Pt, 194Pt, 195mPt, 196Pt, 198Pt), some radionuclides as impurities will be produced during the reactor bombardment. So, using an enriched Pt target will increase the production yield together with a reduction of the impurity production. To separate 199Au radionuclide from the impurities mentioned above, and also to calculate both the chemical yield and the radionuclide purity of 199Au, two chemical separation techniques were applied. In the first technique, 199Au radionuclide was separated from impurities by employing liquid-liquid extraction (LLX) using ethyl acetate. As a result of this separation, the chemical yield of 199Au radionuclide was more than 99%. In the second technique, 199Au was separated by employing LLX using liquid cation exchanger, Di-(2-Ethylhexyl) phosphoric acid (HDEHP). By applying this technique, the chemical yield of 199Au radionuclide was more than 80% consequently. We calculated the theoretical findings and compared the results with the related experimental values.In the second part of the present study, the synthesis of radioactive 199Au nanoparticles (199AuNPs) have been investigated by the Turkevich method with the aim of produce citrate-gold nanoparticles with different sizes of approximately 50 nm. Possible uses and applications of 199Au nanoparticles in medicine are also discussed.

Cargo inspection systems aim to detect illegal goods such as weapons, explosives and narcotics, by imaging the object being inspected such as cargo containers, vehicles, trains, trucks or boats. These systems have been common for the last decade and their use has expanded rapidly. This work examines the necessary radiation standards and how to assess the compliance of inspection systems made in Iran with the standard set by the competent authorities. So, the dose ranges of three Cargo inspection systems made in Iran and one foreign system is compared with the authorized dose range, which results show the fulfillment of international requirements by Iran made inspection systems. It was found that the dose rate of the driver in each inspection operation is less than other sources such as natural exposure. Therefore, the authorized times for drivers to use these systems is determined by annual exposure limit of people.

Patient dosimetry plays the essential role in nuclear medicine performed with various method in clinical and research approaches. There are many methods for internal dosimetry which Monte Carlo code with high accuracy has the crucial place compare to others. The principle reason that Monte Carlo couldn’t performed as the clinical method is the high computation time. This method could be use in the complex geometry such as patient but before the implementation of the code, accreditation should be done. This paper aim to present the method of validation the Gate Monte Carlo codes in PET nuclear medicine. The researches were carried out with experimental tests by head and TLD dosimeters and the results were compared with GATE outputs at the same geometry. In the second steps, ICRP110 phantom in two state of lunge to lunge as a source to target organ and liver to lung considered the MIRD internal dosimetry method had been simulated. The S factor were the results of the simulation codes compared with MCNPX Monte Carlo results in the same conditions. The result has shown the accordance between the simulation and experimental data with high accuracy and highlights the role of Monte Carlo in complex geometry as the high accurate and validate methods.

The increasing development of various aspects of the nuclear technology, including its uses in industry, medicine, electricity generation, etc., resulted in the increment of the amount of emitted radiations, so that the protection against the emitted radiations becomes more important. Therefore, a lot of researches are being done on the different compounds, mixtures and pure materials to make the different shields. In this research, eight different oxides and three concretes with the different compositions have been used to make the different concrete shields. The attenuation coefficient of these shields has been calculated for two energies of 662 and 1460 kV. The results showed that the combination of thallium oxide with all three types of concretes has the highest attenuation coefficient against the photonic radiations comparing to other oxides due to have the highest density. Among the concretes, Mo concrete has the highest attenuation coefficient between all of the concretes due to have the highest density, which can be resulted in the high percentage of the iron in its compositions. As a result, the highest attenuation coefficient, obtained in this study, is related to the new concrete shield that obtained from the combination of Mo concrete and thallium oxide. The results of this research can be used to design and create the different shields and how to mix the amount of their compositions.

One of the reasons for the use of PET radioisotopes in medical research is the presence of a series of positron emitters such as 11C, 13N, 15O, and 18F. The detectors combined with them perform a series of processes similar to natural processes in the body. Another advantage of this method is imaging of metabolic function, which causes early detection of dangerous diseases such as cancerous tumors, cardiovascular diseases, neurological diseases such as epilepsy, Parkinson's disease, and allows the doctor to treat the disease before it develops. In this research, in search of radioisotope production devices with short half-lives, to simulate the depth dose received by a phantom cube of water geometries are 20 cm at a distance of 50 cm from the spring and firing one million photons from a point spring with the energy of 25 MeV Cylindrical water with a radius of 7 cm and a height of 3 mm in order to produce radioisotope F18, Geant tool 4.10.7 has been used and to have safe radiotherapy, the received deep dose has been calculated with appropriate results.

Due to the performance of all stages of imaging processes with ionizing radiation by radiology technologists, they have an effective role in controlling radiation and preparing quality images. In this regard, their knowledge and job skills are necessary to create images with appropriate quality along with the minimum amount of radiation. Therefore, the present study was conducted to investigate the level of knowledge of radiology technologists about the parameters affecting radiation dose in teaching hospitals of Ahvaz University of Medical Sciences. 

This descriptive cross-sectional study was conducted using a questionnaire including demographic characteristics of technologists and questions related to the level of knowledge designed by the researchers of the study, with the participation of 94 radiology technologists in the radiology centers of Ahvaz teaching hospitals. Data were analyzed using using SPSS 24 software and ANOVA and two independent samples t-test.

In this study, the average self-assessment score of the respondents in all areas of knowledge and skills of radiologists is 75.67 and 67.15%, respectively, and therefore at the desired level. The highest knowledge score was related to choosing the appropriate radiation conditions and the lowest scores were related to how to work with the PACS system. According to radiologists, knowledge of radiography techniques and skills in it is very important. There was a statistically significant relationship between gender and knowledge score and type of employment and skill score so that the level of awareness in women was higher than men and people with contract employment gained higher awareness scores.

The results of this study showed that the level of knowledge and skills of radiology technologists working in radiology departments of Ahvaz is acceptable. Holding in-service training courses and continuous evaluation of radiologists and providing the necessary conditions to access up-to-date scientific information for them can be effective in optimizing the quality of images and doses received by patients.

Despite the fact that the harmful effects of ultrasound waves have not been reported in previous studies, these rays are in the group of non-ionizing rays so as a form of energy have the potential to create biological effects when interacting with tissue. Accordingly, guidelines and recommendations have been proposed regarding the adjustment of scan parameters in ultrasound tests, especially pregnancy ultrasound to maintain the safety of patients and the fetus. Therefore, the aim of this study was to evaluate the scanning parameters and safety of common ultrasound tests used in diagnostic ultrasound centers.

This descriptive cross-sectional study was performed by completing 321 checklists designed by researchers in Ahvaz ultrasound centers. Ultrasound examinations including routine pregnancy check-ups, examination of fetal abnormalities and pregnancy problems, initial diagnosis of the disease, and re-examination of cancer recurrence and metastasis were performed. In the examined tests, the standardization of specific parameters of the ultrasound system such as thermal indices (TI), mechanical (MI) and scan time were evaluated.

In general, the maximum allowable values ​​of mechanical and thermal indicators for pregnancy tests are 1.0-0 and 0.4-0, respectively, and for non-pregnancy tests are 2.0-0 and 0.9-0, respectively. In this study, the mean thermal and mechanical indices for non-pregnancy tests were 0.30 ± 0.29 and 0.35 ± 1.07, respectively, and for pregnancy tests were 0.32 ± 0.27 and 0.13 ± 1.15, respectively. Based on this, for non-pregnancy tests, the mean of thermal and mechanical indices and scan time were within the standard and below the recommended values. For pregnancy tests, the mean heat index and scan time were appropriate, while the mean mechanical index was higher than the allowable limit for the first trimester of pregnancy.

The results of this study indicated that the scan parameters used in the ultrasound examinations of Ahvaz imaging centers were appropriate and the examined examinations were relatively safe. However, more attention must be paid regarding the suitability of all scan parameters for pregnancy tests.

In the presented work an industrial and medical based radiography system is fabricated. To design a proper system first of all four sub domain of the whole system is considered namely known as control system, transformer driver, multiplier and hosing system. To control the entire system a Wi-Fi and remote controllable mechanism is considered also it is expected by this controlling system the operator can be in the safe distance from the x ray. On the other hand, to drive a transformer that feeds the multiplier a suitable driver is used based on the x ray tube performance and a chine of multiplier that generates enough voltage deference in the chosen tube is designed. Finally tube hosing that prevents x-ray from scattering in the lab environment is fabricated which is been presented in another paper.

In this research project a special shield made up of lead is designed and produced by our team, in which the production of this shield the next generation of x-ray producers which their accelerators and multipliers aren't together a new form is constructed, considering the fact that for increase in accuracy and lowering the costs the source of the ionized rays is located outside the accelerating compound, hence an unique lead interference is formed by which based on the foundation of the  machine it'll prevent from the leakage of x-rays. The design has been tested several times while taking all the precautions required and Geiger detector established there is no leakage of x-ray. This machine also reduces the risk factors such as forgetting and also difficulty in the utilization of protective equipment and it also helps the new users and will reduce costs meanwhile widening the usage of x-ray producers.

Given that neutron is a non-load-bearing particle that quickly responds to environmental elements and leads to ionization of elements, as well as dispersion that affects neutron spectrum due to environmental factors. Dosage of dispersed neutrons, as well as minimizing dispersion factors is the goal of this research. Calibration can be defined as a set of operations under specified conditions that measure the relationship between the values measured by the measuring instrument or system and the Similarly known well known values of a value.

Nowadays, with the advancement of nano-technology, nanoparticles with high atomic number can be concentrated in tumor cells. The presence of nanoparticles within the tumor causes an increase in the tumor sensitivity to the radiation while healthy tissues nearby get the least damage. In the present study, using the code mcnpx, phantom consisting of a cube with sides of 10 cm containing soft tissue and a tumor with sides of 0.5 cm were considered. In order to investigate the effect of nanoparticles with radius 15, 50 and 100 were used. The results showed that the optimum energy in the presence of nanoparticles with radius 15 and 50

In accelerators operating energies above 7 MV, photoneutrons are produced by the interaction of photonuclear interaction with the heavy metals that constructed the linear accelerator (linac) head. Photoneutrons have destructive biological effects and increase the risk of secondary cancer in healthy organs outside the treatment area. In this study, the effect of flattening filter removal on the spectrum and dose of photoneutrons from the Siemens Primus 15 MV linear accelerator was investigated using the MCNPX2.6 Monte Carlo code. The results showed that removing the flattening filter increased the photon and photoneutron flux at the isocenter. The absorbed doses of photons and photoneutrons dose equivalent per incident electron on the linac target were also increased, without a flattening filter. However, in this case, the photoneutron dose equivalent per 1Gy of the photon absorbed dose at the isocenter is reduced to 50% at different distances from the isocenter.

Today, using nanotechnology, drugs are placed on carriers or nanoparticles and then sent into the target cell. The Nano fluid is magnetically heated in the presence of an alternating magnetic field. In this paper, we investigate how heat is distributed by three nanoparticles of magnetite, cobalt ferrite and nickel ferrite in a brain tumor using an alternating magnetic field. For this purpose, we first considered a model for heat transfer based on body tissue in a cylindrical system, then, using Maple software, we drew the related diagrams. Analyzing the results, we found that the temperature transfer in the heat source is the highest and then decreases.

Abnormal cell proliferation and the body's inability to resolve this problem can lead to cancer. Common methods of cancer treatment have side effects. The use of magnetic nanoparticles under a   magnetic   field is   a   promising   approach in   the treatment   of cancer.   When magnetic nanoparticles are placed in an alternating magnetic field, the fro fluid transfers heat energy and reaches equilibrium.  The effective mechanisms  for  generating  heat  in  hypothermia are  Neel's and  Brownian's relaxation. The specific absorption rate is one of the most important parameters in the design of magnetic nanoparticles for heat therapy. At present, the calorimetric method is used to determine the specific absorption rate of nanoparticles. Tumor warming can cause serious damage to surrounding healthy cells. On the other hand, if the temperature rise is not high enough, the desired treatment can not be achieved. In this paper, we have used a colorimetric method to measure the specific adsorption rate for three nanoparticles of Fe3O4, NiFe2O4, and CoFe2O4.

Nuclear medicine personnel are exposed to radiation during radiopharmaceutical preparation, injection, and imaging. One of the most widely used devices in nuclear medicine is the Single Photon Computed Tomography (SPECT). Injectable radioisotopes in the field of nuclear medicine emit gamma rays, and because gamma rays fall into the category of ionizing radiation, they can break chemical bonds in contact with tissue and cause adverse reactions. The Linear No Threshold model (LNT) considers exposure to any amount of radiation to increase the risk of cancer, and the International Committee for Radiation Protection (ICRP) has set a dose limit for the general public and occupation. So, in this study, we decided to estimate the received dose by personnel and attendant people with environmental and individual monitoring. For two months' environmental rate dose by using Geiger Muller dosimeter, in four nuclear medicine departments, effective dose of personnel by using film badge dosimeter and hand received dose of personnel in contact with radiopharmaceuticals by using finger dosimeter, was monitored. The obtained rate dose was comparable to background radiation, and being in such a place would not be dangerous for companions and personnel. The absorbed dose of the whole body and hands of the employees was much lower than the declared limit. However, according to the ALARA principle recommendation, it is recommended to observe the protection principles and in addition to the film badge, a finger dosimeter should be used to monitor personnel.

In term of annual collective effective dose, computed tomography (CT) has the highest radiation risks among the other imaging modality and its utilization is increasing every year. Accordingly, due to the high sensitivity of children to radiation exposure, radiation protection has to be considered especially in young patients.

The aim of this study was to determine the justifiability and alternative modality of brain CT scans that performed on patients aged fewer than 20.

CT scan results were evaluated for 145 patients who entered an emergency department in Yazd, Iran, over six month period. Patients were categorized in four different age groups and the justification of CT examinations, based on reliable references was evaluated for them.

About seventy percent of scans did not show any specific clinical complication. Also, based on the referral guidelines for recommended imaging modality, about 12% of scans could alternate with MRI and 18% of them are justified.

According to the high percentage of scans with normal results, it may be important to pay attention to the availability, retraining and consideration to a comprehensive CT scan prescribing protocols, especially for children. In order to reduce the prescribing of CT Scans in unjustified cases, the increasing capacity of MRI equipment, in terms of device operation hours during the day, can be helpful.

Gamma-ray industrial radiography is performed with the help of a gamma projector, and a gamma projector is a device in which a radionuclide source produced according to the standard (ISO 2919) is placed inside a shield (often depleted of uranium) and equipped with equipment and Appropriate accessories, while keeping the safe during industrial radiography work, provide the possibility of transferring the source to the radiation point, by remotely. There are two categories of direct crossing channels and S-shaped channels. In direct channel , it is possible for the holder containing the source to come out of the gamma projector due to defects in the gamma projector, such as a broken gamma projector lock, which can lead to accidents during transport and radiography operations.Due to the portable use of this type of gamma projectors , this type of gamma projectors are mainly used as a B (U) transport package and the terms and conditions related to this type of indoor radioactive package are mandatory for them.The reasons for expiring this type of gamma projectors are as follows:1. Non-compliance of gamma projectors with direct radiation source channel with the latest requirements of ISO-3999 standard2. expiring the design certificate of B (U) type packages of this type of gamma projectorsBased on the decision of the regulatory body on 07/11/1394, it was decided that from the mentioned date, purchase, sale, transfer and international transportation of all gamma projectors:A- Gammamat projectors TI, TIF, TIFF, S modelsB- Tech-ops 660 and Gammarid C- Gammavolt SU-50, SU-100Banned and companies with TI, TIF, TIFF, S gamma projector models for 2 years and companies with gamma projector SU-50, SU-100 and Tech-ops 660 and Gamarid for 3 years are allowed to use In industrial radiography operations and then they have to drop the mentioned gamma projectors.According to the statistics of accidents in the country's radiography activity, which were mostly related to gamma projectors with direct radiation passage channel, the expiring of this type of non-standard projectors resulted in a decrease in accidents in radiography activities, especially accidents related to radiography equipment errors.Also, the evaluations made regarding the ratio of the number of loaded projectors that are used in the country to the total number of projectors in the country before the implementation of the decree and its comparison with the same ratio after the implementation of the decree, show that expiring this number of projectors has not led to a shortage of projectors in use in the country and also this issue has not caused a disruption in the amount of radiography work of related companies in the country.

Scattering factor (Scp) is one of the important factors in the dosimetry of medical accelerators. Variation of scattering factor is one of the factors that affect the dose received by the patient. In this research is tried to simulate the geometry of the compact model linear accelerator using Geant4 code and the appropriate phase space of this accelerator has been extracted using electron source data. Phase space are required to increase the accuracy in Monte Carlo calculations. Phase space data include the gamma rays energy and angular spectrum that generated by the 6 MeV electrons with 0.07 FWHM. Comparison between simulated and practical values of SCP ​​shows that the introduced phase space is a suitable source for dosimetric calculations of compact linear accelerometer.