International Journal of Radiation Research
Year:2005 | Volume:3 | Issue:1|Papers Count:10

Background: Monte Carlo simulation has been used by many researchers to calculate organ and effective dose of patients arising from conventional X-ray examinations. In this study the radiation transport code, MCNP-4C, has been used to perform Monte Carlo simulations to estimate radiation dose delivered to different organs in conventional X-ray examinations. Material and Methods: In this work we have made use of ORNL mathematical phantoms with few modifications which have been made. The source has been defined as a point source, emitting photons into a solid angle. The X-ray beam was shaped by a collimator to produce a rectangular field at the midline of the phantom. Results: To validate the simulation executed in this study normalized organs doses to unit ESD for hermaphrodite phantom were computed. Our results were compared with corresponding values presented by NRPB. In general organs doses obtained by application of MCNP-4C (present study) and corresponding values presented in NRPB were in good agreement. For further evaluation of our phantom, the values acquired for organ and effective doses by MCNP-4C and ODS-60 were compared. Conclusion: The technique we have developed is capable of estimating organ and effective doses with a better accuracy than dose values obtained by employment of NRPB and ODS-60 technique.

The 1st issue of the Iranian Journal of Radiation Research (IJRR) was published two years ago (June 2003). This journal was initiated to bring together the various disciplines of radiation oncology, radiation biology, medical physics, nuclear medicine and other related subjects to intensify the dialogue between basic and clinical researchers especially those working in Iran. Within the last two years, this journal has tried to offer an ideal platform for the exchange of detailed scientific information concerning the latest developments in the field of radiation research, from various institutes, hospitals or even individuals. IJRR has been one of the specialized journals when published 2 years ago. The executive committee of the journal has been anxious about the quality and quantity of papers received by the IJRR office. The reason is that, the research activities in these fields are unexplored. Then, we believed that there might not be sufficient numbers of articles to be published in a specialized magazine as IJRR. Now, only a little over 2 years we have realized potential peoples and centers working in this area, not only in Iran but in other countries who contributed sincerely to the journal so that we are not worried about the materials to be published. We have realized that the existence of such a unique journal is a must both for Iran and the researchers in the region. Shortly after publishing the 1st issue, we tried to computerize all activities in the editorial office, including online review by our reviewers. The journal’s website is one of the most complete websites among Iranian journals with search capabilities and free access to abstracts and full PDF texts by readers and our visitors. The scientific quality of the journal specifically depends on the quality of papers submitted and the keen attention of the journal’s reviewers. These efforts were led to recognition of the journal as a scientific and academic research source by the ministry of Health and Medical Education. It has also been indexed by Index Medicus for Eastern Mediterranean Region (IMEMR). And now, in an annual qualification of scientific medical journals, IJRR is ranked among the highest scored journals.We are proud to publish the 3rd volume of the journal with a short delay. To fulfill the interest of our readers and taking another step toward being internationally published in the field of radiation research, we have made some changes in the structural appearance and reference citation according to Vancouver’s format. We would like to express our special thanks to our editorial board for their help and suggestions, all reviewers for their sincere help and careful review of the articles and my colleagues at the editorial and publishing office. I doubt we could publish this journal without their interest and efforts. IJRR is looking forward to receiving the invaluable papers from Iranian and foreigner scientists to be published in the forthcoming issues.

Background: Although Electronic Portal imaging Devices (EPIDs) have originally developed for positioning verification, they can also be used for dosimetric purposes. In the current work, the dose response of minimum detectable thickness of a Scanning Liquid filled Ion Chamber EPID, SLIC-EPID, and the variation of transmitted dose with the shift of inhomogeneity inside of phantom was also evaluated were investigated. Materials and Methods: The SLIC-EPID pixel values were converted to the dose values using ionization chamber calibration and KODAK Extended Dose Range films (EDR2 films). The variation of EPID dose values with phantom thickness was investigated. In order to find the rate of dose deposited per centimetre of phantom, several reference points were defined and the variation of dose delivered to the points in the vicinity of reference points was investigated. Two cm thick foam layer, as air gap, was shifted in the beam direction to evaluate the variation of transmitted dose with the shift of inhomogeneity position inside of phantom.Results: An exponential decrease of the transmitted dose values was observed with the increase of the thickness of attenuators. The maximum and minimum rate of dose deposited per unit of phantom thickness was found to be 5.45% /cm and 3.78% /cm, respectively. Due to the reproducibility and noise level of SLIC-EPID, a 0.5 cm of thickness can be detected with a good reliability. The relative error of EPID dose values increases with an increase of phantom thickness for both data sets. The relative error did not exceed 0.7%. No significant variation in transmitted dose inplane and crossplane profiles were found with the shift of inhomogeneity in the beam direction.Conclusion: The minimum detectable thickness is an important factor to evaluate an imager for dosimetric purposes. The SLIC-EPID can be used as a reliable two-dimensional dosimeter.

Backgrounds: MD-55-2 is one of the Radiochromic film models with the sensitivity suitable for dose measurements ranging from 5 to 100 Gy. However, this lower limit makes the film impractical for its applications in many areas such as brachytherapy source dosimetry. Materials and methods: In this project, the useful range of the film has been extended by using a multilayer film technique. In this technique, single-, double-, and triple- layers of films were exposed to the doses ranging from 0.5 to 10 Gy using a Co-60 photon beam. Calibration curves for corresponding layers of films were obtained with a spectrophotometer using a 680nm wavelength.Results: The results indicated that the sensitivities of double and triple layers were approximately 200% and 300%, respectively, higher than a single-layer film. The impact of multilayer film arrangement on the energy dependence of the MD-55-2 Radiochromic film has also been examined using 100KVp, 80 KVp, and 6 MV X-ray beams. The results indicated an insignificant (within 5%) change in film responses with the beam energy. Conclusion: Therefore, the multilayer technique enhances the Radiochromic film sensitivity and expands its application to the low dose range in field of brachytherapy source dosimetry.

Background: There are relatively rich uranium mines in regions of Saghand and Bafgh in Yazd province. This survey was carried out to provide a map of ambient gamma radiation of Yazd province and the probable effects of the existence of these mines on background radiation dose rates. Materials and Methods: The measurements of the outdoor and indoor–environmental exposures (including cosmic and terrestrial components) were accomplished by a portable Geiger Muller detector in the five areas in each of eight big cities of Yazd province.Results: The average exposure rates of indoor and outdoor ambient of Yazd province were 13.9 ±0.7 µRh-1 and 11.6 ±0.8 µRh-1 respectively. The average dose rates in air, resulting from gamma background radiation of indoor and outdoor were 122±6.8 nSvh-1 and 101.4 ±7.4 nSvh-1 respectively. The annual average of equivalent dose in air was found to be 1.03 ± 0.05 mSv, and the annual average of effective dose was 0.72 mSv.Conclusion: The results of this study in comparison with the same measurements in some other cities in Iran such as Isfahan and Tabriz, proves that the existence of uranium mines doesn’t affect gamma background radiation of Yazd province.

Background: Radioprotective effects of famotidine, an antagonist of H2 receptor clinically used for peptic ulcer treatment, was previously shown on radiation-induced micronuclei and chromosomal aberration in human peripheral blood lymphocytes and mouse bone marrow cells. This study was conducted to investigate radioprotective property of famotidine against radiation induced apoptosis in human peripheral blood leukocytes. Materials and Methods: Peripheral blood was obtained from 6 healthy volunteers including three males and three females. 12 µL of blood sample diluted in 1 ml RPMI-1640 supplemented with antibiotics and foetal calf serum was irradiated a dose of 8 Gy gamma rays generated from a Co-60 source at a dose rate of 1.27 Gy/min. After 48 h incubation in a 37 oC incubator, cells embedded in low melting point agarose were transferred to a slide precoated with normal agarose. Cells were lysed and subjected to electrophoresis under neutral condition. Slides were then stained with ethidium bromide and analysed under a fluorescence microscope. 500 cells were analysed for each sample for the presence of apoptosis. The data were statistically evaluated using Man-Whitney non-parametric and ANOVA tests.Results: Results show a significant increase in apoptosis induction following 8 Gy γ-irradiation comparing with controls (p<0.001). The presence of famotidine at 50 and 100 µg/ml did not show any protective effect against radiation induced apoptosis; however, the presence of famotidine at higher concentration (200 µg/ml) significantly deceased radiation induced apoptosis (p<0.001).Conclusion: The obtained results suggest that famotidine suppresses radiation-induced apoptosis at 200 µg/ml, probably via OH radical scavenging and an intracellular antioxidation mechanism. Famotidine appears to be a useful candidate for the future development of post-irradiation radioprotectors.

Background: Delivering the radiation dose to the target volume and minimizing the dose to normal tissues are the main objectives in radiotherapy. The aim of our study is to enhance the contrast of the portal image to increase the accuracy of delineation of the organs in the irradiation field. Methods: The software was written based on local enhancement of the pixel values in image matrix. The portal images were digitized by charged coupled device (CCD) in compatible format to be read with this program. This program was applied as an m-file in MATLAB imaging tool box to the matrices of the portal images. The imaging parameters before and after application of the program were compared. Results: The quantitative information of images was obtained. Analysis of the mean and standard deviations of the results has shown that the difference of the criteria between two groups of the images is significant (p< 0.01). In qualitative analysis, final images scores were based on “special weight “. The result of this test confirms the superior quality of the post-processed images from the professional view point. Conclusion: Superiority of final images within the three studied parameters by the experts (superiority of lung image, superiority of thorax and its soft tissue images) can be used to increase the accuracy of the treatment set up and decrease the probability of normal tissue complications.

We are reporting a 43-year-old female breast cancer case with a solitary metastatic adenocarcinoma in clivus. This patient with a stage II (T1N1M0) breast cancer history has been followed for 7 years. Modified Radical Mastectomy (MRM) and 6 courses chemotherapy with CMF (Cyclophosphamide, Metotrexate, 5FU) regimen were done for her at the time of diagnosis. Also, she took tamoxifen twenty mg per day for five years. She had no evidence of disease for 6 years. About one year ago she suffered diplopia and headaches for two months. MRI and CT scan studies showed a well defined mass in her clivus. Biopsy of mass was performed and pathologic report was metastatic adenocarcinoma.

Background: 226 Ra and 228 Ra contents in foodstuffs of Ramsar which is a coastal city in the northern part of Iran were determined by gamma spectrometry. Measurement results together with food consumption rates were used to estimate annual effective dose from 226 Ra and 228 Ra, due to consumption of food stuffs by inhabitants of Ramsar city. Materials and Methods: A total of 33 samples from 11 different foodstuffs including root vegetables (beetroot), leafy vegetables (lettuce, parsley and spinach) and tea, meat, chicken, pea, broad bean, rice, and cheese were purchased from markets of Ramsar city and were analyzed for their 226Ra and 228Ra concentration. 1-8 kg of fresh weight sample was placed in Marinnelli beaker and sealed. The measurement of natural radioactivity levels as performed by gamma-spectrometry system, using a high purity germanium (HPGe) detector with 40% relative efficiency.Results: The highest concentrations of 226Ra and 228 Ra were determined in tea samples with 1570 and 1140 mBq/kg , respectively , and the lowest concentration of 226Ra was in pea, cheese, chicken, broad bean, and beetroot.Conclusion: The maximum estimated annual effective dose from 226 Ra and 228 Ra due to consumption of foodstuffs were determined to be 19.22 and 0.71 mSv from rice and meat samples respectively, where as, the minimum estimated annual effective dose for 226Ra was 0.017, 0.018 and 0.019 mSv from beetroot, cheese and pea samples respectively.

Background: Design of the production system for Iodine-123 has begun recently in nuclear research centre of agricultural and medicine (NRCAM). The production system consists of pipes for xenon gas transfer, equipped with 10 valves, 3 heaters, fluid nitrogen and 2 vacuum pumps. In the first prototype the function of elements was being done manually by an operator. Because dispensing radiopharmaceuticals manually involves receiving radiation dose by operators, therefore, automation is very important step in radiopharmaceutical production. Materials and Methods: The automatic system for production of Iodine-123 is PLC /135u Siemens, which is designed and installed for the first time in Iran. The PLC was connected to the production system through relays. By programming the CPU of the PLC, start up and control of the production procedure was executed automatically.Results: Automation leads to reduced presence of operator for Iodine-123 production. We were also able to record storage and transfer of materials and minimize risk of error.Conclusion: Automation in production of radiopharmaceutical may lead to reduced radiation dose to personnel and achieved better dispensing precision.