Showing papers in "Iranian Journal of Radiation Research in 2009"

Radioactivity in some sachet drinking water samples produced in Nigeria

Abstract: *Corresponding author: Dr. Oladele Samuel Ajayi Department of Physics, Federal University of Technology, P.M.B 704, Akure, Ondo State, Nigeria. E-mail: ajayisam1089@yahoo.com Background: Activity concentrations of 40K, 226Ra and 228Ra were measured in some sachet drinking water samples produced in Nigeria. Materials and Methods: The measurement was done by using high-purity germanium (HPGe) detector (Canberra Industries Inc.). The measured activity concentrations for 226Ra (U-series) and 228Ra (Thseries) were used with their ingested dose conversion factors to estimate annual effective doses for the International Commission on Radiological Protection (ICRP) age groups 0 – 1y, 1 – 2y, 2 – 7y, 7 – 12y, 12 – 17y and >17y from consumption of the water samples. Results: Measured activity concentration values varied from 0.57±0.21 to 34.08±5.61 Bq l-1, 2.22±0.97 to 15.50±4.51 Bq l-1 and 0.04±0.01 to 7.04±1.16 Bq l-1 for the radionuclides respectively. Estimated total annual effective doses varied from 4.73 to 49.13, 1.21 to 12.26, 0.86 to 8.54, 1.22 to 11.66, 3.40 to 28.98 and 0.68 to 5.04 mSv y-1 for the age groups respectively. The highest total annual effective dose was found in Tisco sample while the lowest was found in Focar sample. Conclusion: The total annual effective dose in all samples considerably exceeded the average worldwide ingestion exposure dose value of 0.12 mSv y-1 from uranium and thorium series reported by the United Nations Scientific Committee on Effects of Atomic Radiations (UNSCEAR). Therefore the Nigeria populace is advised to consume less of these water samples. Iran. J.

Determination of 40k concentration in milk samples consumed in tehran-iran and estimation of its annual effective dose

Abstract: K is the most important natural radionuclide in the environment, its concentration was measured for all milk and milk powder samples consumed in Tehran-Iran. Milk was chosen, since because it is a reliable indicator of the general population intake of certain radionuclide, and many environmental programs have been applied for its safety.

Activity concentration of radionuclides in plants in the environment of Western Ghats

Abstract: 238 U, 232 Th, 40 K and fallout radionuclides 210 Po in different plant species in tropical forest of western Ghats environment, India, is presented. Material and Methods: The Top storey, Short storey, Shrubs and Epiphytic plant species were sampled and concentration of these radionuclides in plant and soil were measured by employing a gamma ray spectrometer and an alpha counter. Results: The soil-plant concentration ratio shows the variation of radionuclide accumulation in different species while a wild plant Elaeocarpus oblongus and epiphytic plants indicated preferential uptake of these radionuclides. Conclusion: The dust particles dust trapped in the root system of epiphytic plants could be used as bioindicator to monitor fallout radionuclides in the Western Ghats. The concentration of 232 Th and 40 K in leaves depends on the age of the leaves

Determination of the optimum filter for qualitative and quantitative 99mTc myocardial SPECT imaging

Abstract: *Corresponding author: Muhammad Nur Salihin Yusoff, Medical Radiation Programme, School of Health Science, University Science Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia. E-mail: mnsalihin@gmail.com Background: Butterworth, Gaussian, Hamming, Hanning, and Parzen are commonly used SPECT filters during filtered back-projection (FBP) reconstruction, which greatly affect the quality and size accuracy of image. Materials and Methods: This study involved a cardiac phantom in which 1.10 cm thick cold defect was inserted into its myocardium wall and filled with 4.0 μCi/ml (0.148 MBq/ml) 99mTc concentration. The cardiac insert was then put into a cylindrical tank which was filled with 1.2 μCi/ml (0.044 MBq/ml) 99mTc concentration as background. 272 combinations of filter parameters were selected from those filters and applied on image. The measurements of count in myocardium, background, and defect regions of interest (ROI) were performed on each filtered image. Those measurements were then used to calculate contrast, signal-to-noise ratio (SNR), and defect size. For every filter, each criterion was graded (1 to 100) and then summed at their specific setting for total comparison. Results: The results show that, the different filter types produced myocardial image with different contrast, SNR, and defect size. For contrast and SNR, Gaussian filter was the best, while Parzen filter was the best in producing accurate defect size. However, Butterworth filter was found the best for trade off between contrast, SNR, and defect size accuracy. Conclusion: Selection of filter should consider the type of analysis, whether qualitatively or quantitatively. Qualitative analysis depends on image quality which is denoted by high contrast and SNR, thus Gaussian filter was suggested. Instead, the Butterworth filter was suggested for quantitative analysis as it is greatly dependent on both, image quality and size accuracy. Iran. J. Radiat. Res., 2009; 6 (4): 173­182

Concentration of radon, thoron and their progeny levels in different types of floorings, walls, rooms and building materials

Abstract: Background: Radon, thoron and their progenies are the most important contributions to human exposure from natural sources. Radon exists in soil gas, building materials, Indoor atmosphere etc. Among all the natural sources of radiation dose to human beings, inhalation of radon contributes a lot. The work presented here emphasizes the long term measurements of radon, thoron and their progeny concentrations in about 100 dwellings using solid state nuclear track detectors. Materials and Methods: Measurements were made using dosimeters and the concentrations were estimated by knowing the track density of films through spark counter, and sensitivity factor for bare, filter and membrane films. Results: Presence of radon and thoron in houses is the effect of several aspects such as the activity concentrations of uranium, radium and thorium in the local soil, building materials, ventilation of houses and also entry of radon into houses through the cracks in floor/wall. Conclusion: The observations reveal that the concentrations of radon and/or thoron are relatively higher in granite than in concrete, cement and bricks. In continuation to this the concentration observed in bathrooms is more compared to kitchen, bedroom and living rooms. This study discloses that the residential rooms of good ventilation will avoid the health hazards due to radon and its rich materials. Iran. J. Radiat. Res., 2009; 7 (1): 1­9

Gonad, bone marrow and effective dose to the population of more than 90 towns and cities of Iran, arising from environmental gamma radiation

Abstract: Background: Since 1996 the assessment of environmental gamma radiation dose in residential areas of Iranian towns and cities has been accomplished for 10 counties. As a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. The location of individual station was studied closely to comply with recommended conditions in the literature. Materials and Methods: RDS-110 was employed to measure gamma dose rate for one hour. Average annual dose rates plus conversion coefficients were employed to estimate gonad, bone marrow, equivalent and effective dose. Result: Minimum and maximum annual bone marrow and gonad dose equivalent attributed to environmental gamma are 0.24 mSvy -1 (for both tissues) and 1.44 and 1.46 mSvy-1, respectively. Conclusion: Average gonad and bone marrow doses for North Khorasan, Boshehr and Hormozgan provinces were less than the corresponding values for normal area. Iran. J. Radiat. Res., 2009; 7 (1): 41­47

Iranian physicians' knowledge about radiation dose, received by patients in diagnostic radiology

Abstract: Background: Although ionizing radiation is widely used to diagnose many diseases, the relevant hazards are known to be as an important limitation of its application. It is believed that the awareness of ionizing radiation dose values is one of the main stages in patient's radiation protection. The purpose of this study has been to investigate the level of physicians' knowledge about radiation doses received by patients in radiological examinations. Materials and Methods: A questionnaire was designed and the most commonly requested radiological investigations were listed. Participants (155 physicians) were asked to identify the average dose of radiation received by patients when they underwent a posterior-anterior hand X-ray. Then, it was utilized to represent a single dose of radiation, and physicians were asked to estimate the equivalent doses of radiation for other radiological examinations. Several questions were also included about dose measurement's units and low exposure risk investigations. Results: The results indicated that only 58.3% of physicians know the units of radiation absorb dose measurement units. Most of them could not correctly estimate the amount of radiation dose received by patients in a routine radiography of hand and majority of them underestimated the radiation dose of other radiological examinations. Conclusion: Despite of passing medical physics course, during studentship, it does seem that most of medical doctors did not have enough knowledge about the amount of radiation received by patients led for diagnostic radiology investigations. Iran. J. Radiat. Res., 2009; 6 (4): 207­212

Effect of ionizing radiation on development process of t-cell population lymphocytes in chernobyl children

Abstract: Background: The aim of preliminary study was determined development process status of T-cell population lymphocytes in Ukrainian children after 22 years from Chernobyl accident for next feasibility study. Material and Method: 150 participants aged 6 to 16 years are included in three groups: Group I (n=65), 30 to 60 km from center accident at zone 3th, Group II (n=65) 60 to 90 km from same location at zone 4th and control group (n=20) from Kiev, 100 km from same location. Peripheral blood leukocytes from buffy coats were analyzed for T-lymphocytes population such as T-lymphocytes (CD3), T-helper (CD4) and T-cytotoxic (CD8) by roseting method using erythrocytes that conjugated with monoclonal antibody against CD3, CD4, and CD8 receptors; then CD4/CD8 ratio were calculated. Results: Percentage of CD3 and CD4 in groups II and I decreased significantly in compared to control group at P<0.001. Percent of CD8 decreased significantly in group I compared to control group at P <0.001. CD4/ CD8 ratio decreased significantly in-group I comparison to control group at P=0.02. Leucocytes count in groups II and I have not changed significantly in comparison to control group (P=0.09,P=0.4) but in group II, it was significantly different in comparison to group I at P <0.008. Conclusion: Our data show that after 2 decade of Chernobyl accident, ionizing radiation may have affected the developmental processes of T-cell population. Iran. J. Radiat. Res., 2009; 7 (3): 127­133

Simulation of the shielding effects of an applicator on the aapm tg-43 parameters of cs-137 selectron ldr brachytherapy sources

Abstract: Background: The dose rate distribution delivered by a low dose rate 137Cs pellet source, a spherical source used within the source trains of the Selectron gynecological brachytherapy system, was investigated using the MCNP4C Monte Carlo code. Materials and Methods: The calculations were performed in both water and Plexiglas and the absolute dose rate distribution for a single pellet source and the AAPM TG-43 parameters were computed. A spherical phantom with dimensions large enough (60 cm) was used to provide full scattering conditions. In order to score dose at different distances from the source centre, this sphere was divided into a set of 600 concentric spherical shells of 0.05 cm thickness. The calculations were performed up to a distance of 10 cm from the source centre. To calculate the effect of the applicator and dummy pellets on dose rate constant and radial dose function, a single pellet source was simulated inside the vaginal applicator, and spherical tally cells with radius of 0.05 cm were used in the simulations. The F6 tally was used to score the absolute dose rate at a given point in the phantom. Results: The dose rate constant for a single active pellet was found to be 1.102±0.007 cGyh -1 U -1 , and the dose rate constant for an active pellet inside the applicator was 1.095±0.009 cGyh-1U-1. The tabulated data and 5th order polynomial fit coefficients for the radial dose function along with the dose rate constant are provided for both cases. The effect of applicator and dummy pellets on anisotropy function of the source was also investigated. Conclusion: The error resulting from ignoring the applicator was reduced using the data of a single pellet. The results indicate that F(r, θ) decreases towards the applicator. Iran. J. Radiat. Res., 2009; 7 (3): 135­140

Targetry for cyclotron production of no-carrieradded cadmium-109 from natag (p,n)109cd reaction

Abstract: Background: Solid targets that consist of powder and electrodeposited targets are used commonly to produce radionuclides by accelerators. Since silver is easily electrodeposited in cyanide baths and has a very excellent thermal conductivity, the electrodeposited target is preferable to produce 109 Cd. To avoid cracking or peeling of the target during bombardment, it should have a level surface and a good adhesion to substrate. Hence, suitable targetry has extraordinary importance for the interested radionuclide production. Materials and Methods: Excitation function of cadmium-109 via nat Ag (p,n) 109 Cd reaction was investigated by using ALICE-91 code. The required thickness of the silver deposit was calculated by SRIM code. Theoretical yield was calculated by means of Simpson numerical integral method. Silver was electrodeposited on copper backing by the cyanide bath. The prepared targets were examined with morphology and thermal shock tests. Results: The most favorable beam energy was determined as 15 MeV. The desired thickness was determined to be up to 48 µm; the theoretical calculated yield was 2.69 µCi/µA·h. Scanning electron microscope (SEM) photomicrographs and thermal shock tests represented excellent quality of the electrodeposited target. Conclusion: The present study suggested a good potentiality of cadmium-109 production by induced proton on electrodeposited silver targets. Iran. J. Radiat. Res., 2009; 6 (4): 201­206

Verifying the accuracy of dose distribution in Gamma Knife unit in presence of inhomogeneities using PAGAT polymer gel dosimeter and MC simulation

Abstract: Background: Polymer gel dosimetry is still the only dosimetry method for direct measuring of threedimensional dose distributions. MRI Polymer gel dosimeters are tissue equivalent and can act as a phantom material. In this study the obtained isodose maps with PAGAT polymer gel dosimeter were compared to those calculated with EGSnrs for singleshot irradiations of 8 and 18 mm collimators of Gamma Knife (GK) unit in homogeneous and inhomogeneous phantoms. Materials and Methods: A custom-built, 16 cm diameter spherical Plexiglas head phantom was. Inside the phantom, there was one cubic cutout for insertion of gel phantoms, and another cutout for inserting the inhomogeneities. The phantoms were scanned with a Siemens clinical 1.5 T MRI scanner. The multiple spin-echo sequence with 32 echoes was used for the MRI scans. Results: The results of measurement and simulation in homogeneous and inhomogeneous phantoms showed that the presence of inhomogeneities in head phantom could cause spatial uncertainty higher than ±2 mm and dose uncertainty higher than 7%. Conclusion: the presence of inhomogeneities could cause dose differences which were not in accordance with accuracy in treatment with GK radiosurgery. Moreover, the findings of Monte Carlo calculation revealed that the applied simulation code (EGSnrc) was a proper tool for evaluation of 3D dose distribution in GK unit. Iran. J. Radiat. Res., 2009; 7 (1): 49­56

Does whole body exposure to GSM-950 MHz electromagnetic fields affect acquisition and consolidation of spatial information in rats?

Abstract: Background: This study was planned to examine the effects of whole-body exposure to GSM-950 MHz electromagnetic fields (EMFs) on acquisition and consolidation of spatial memory in rats using a water maze task. Materials and Methods: In experiment 1, the animals were given two blocks of five trials per day for three consecutive days in a water maze task. The interval between blocks was 4h. Before each training session, the animals were exposed to 950 MHz EMFs for 45 min with lower- (0.835 mW/cm2) or higher-power (1.166 mW/cm 2 ) densities. In experiment 2, the animals were given two blocks of 5 trials with a 3 min interval between blocks. Immediately after the last trial, they were exposed to EMFs for 45 min with lower- or higher-power densities. In both experiments, 48 h after the last training day a 60 s probe test was done. Results: Results from experiment1 (pre-training exposure to EMFs) indicated no significant differences in performances of exposed and non-exposed groups either during acquisition (learning) or during probe test (memory retention). Results from experiment 2 (posttraining exposure to EMFs) also indicated no significant differences among groups during acquisition or probe test. Conclusion: In these experiments, no effect of exposure to 950 MHz on acquisition or consolidation of spatial navigation of rats in a water maze was detected. Iran. J. Radiat. Res., 2009; 7 (1): 57­62

Seasonal variation of radon, thoron and their progeny levels in dwellings of Haryana and Western Uttar Pradesh

Abstract: Background: Radon and thoron are invisible, odorless, heavy and radioactive gases which are ubiquitously present in dwellings and in the environment. In the present work, seasonal variation of indoor radon, thoron and their progeny concentrations has been studied in the dwellings of industrially polluted cities in District Faridabad, Haryana and District Mathura in Uttar Pradesh. Materials and Methods: LR -115, Type- II (Kodak Pathe, France), peelable, plastic track detectors commonly known as solid state nuclear track detectors (SSNTDs) were used to measure the radon thoron concentration over long integrated times. The measurements were carried out in the mixed field of radon and thoron and the detectors were exposed for about 90 days. Results: The average value of radon and thoron concentration in the dwellings varied from 23.5 Bq/m3 to 65.2 Bq/m3 and 9.8 Bq/m 3 to 18.7 Bq/m 3 respectively in different seasons. The average annual exposure and annual effective dose in living rooms due to radon and thoron progeny was estimated to be 0.195 WLM (working level month) and 0.74 mSv respectively. The average life time fatality risk of lung cancer from the chronic radon and thoron progeny exposure was estimated to be 5.8 ´ 10-3 (0.58%). Conclusion: The seasonal variations of measured radon levels in the environment of LPG bottling plant, radon-thoron levels and inhalation dose due to radon and thoron and their progeny in dwellings indicate that the levels were higher in winter (October to January) than in summer (April to July). Iran. J. Radiat. Res., 2009; 7 (2): 79­84

Shielding evaluation of a typical radiography department: a comparison between NCRP reports No.49 and 147

Abstract: *Corresponding author: Dr. Asghar Mesbahi, Department of Medical Physics, Medical School, Tabriz university of Medical Sciences, Tabriz, Iran. Fax: +98 411 3364660 E-mail: asgharmesbahi@yahoo.com Background: Designing and shielding of an appropriate radiography room has been one of the major concerns of radiation scientists since the first decade after the invention of X-rays. Recently, report No.147 of National Council on Radiation Protection and Measurements (NCRP) has been published. In this study the researchers have investigated the effect of new report recommendation on primary and secondary barriers thicknesses in comparison to NCRP 49, and 116 recommendations. Materials and Methods: To calculate the walls thickness of a conventional radiography room, the workload of a radiography room of a university hospital was determined by recording the number of exposures, mAs and kVp for each patient during six months. Three types of calculations were done: (1) Using NCRP 49 formulations and dose limits (2) Using the NCRP 49 formulations and NCRP116 dose limits and (3) Using the NCRP 147 recommendations. Results: The estimated workload was 172 mA min wk-1 for the studied radiography room which was slightly lower than the workload recommended by NCRP147. The results showed that using the NCRP49 formulation and NCRP116 dose limits, the barriers thickness increases substantially. Moreover, the dose limits were lower in NCRP 147, using the third method. The primary barrier thickness is decreased considerably in comparison to two other methods. For the secondary barrier the results of the two methods (1) and (3) did not differ and remained the same. Conclusion: Application of NCRP 49 and NCRP116 dose limits for radiography room shielding (second method) overestimated the primary and secondary barriers thickness, significantly. But, applying NCRP 147, not only the new dose limits were considered, but also the cost of primary barrier construction was reduced. Iran. J. Radiat. Res., 2009; 6 (4): 183­188

Rheological properties of blood after whole body gamma-irradiation

Abstract: Background: The study of rheological properties of blood has special interest; since it is a circulating fluid exposed to shear rates during its life time. This work aims to investigate the influence of whole body gamma irradiation on the rheological properties of rat’s blood. The applied shear rate was from 12 to 375 s -1 . Low shear viscosity (up to 100 s -1 ) depends mainly on the erythrocytes aggregation while the high shear viscosity depends on the erythrocytes deformability. Materials and Methods: Adult male rats were exposed to 1, 2.5, 3.5, 5, 7 and 9 Gy single doses. The consistency index, apparent viscosity, yield stress and aggregation index were increased after exposure to gamma radiation. The dielectric properties of the erythrocytes, in the low frequency range (60 Hz to 40 kHz), were measured in order to investigate the changes in the membrane surface charge. Results: The results obtained indicate that the viscosity, consistency index and yield stress increased after the exposure to the lowest dose taken; 1 Gy, and continued to increase as the exposure dose increased up to dose 7 Gy and then decrease after exposure to 9 Gy. The relative permittivity and relaxation time showed significant decrease after exposure to the lowest dose and continue to decrease as the dose increased. Conclusion: The obtained results can be attributed to the decrease of membrane surface charge after exposure to gamma radiation. The decrease in the membrane surface charge is known to decrease the repulsion between the cells and increase blood viscosity. Iran. J. Radiat. Res., 2009; 7 (1): 11­17

Patient dose values during interventional cardiology examinations in Yazd hospital, Iran

Abstract: Background: The number of interventional cardiology (IC) procedures has increased rapidly. coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) are now widely performed as a matter of routine, and they are considered safe procedures for experienced cardiologists. However, it is also known that these procedures are associated with high radiation doses due to long fluoroscopy time (T), and large number of cineradiography frames (F). These levels of radiation may even lead to radiation skin injuries under certain conditions. Materials and Methods: A detailed study of radiation doses received by 168 patients who underwent coronary angiography (CA), and 84 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) using 3 angiography X-ray systems in two hospitals of Yazd-Iran is presented. An air kerma-area product (KAP) meter was used for patient dosimetry. KAP, fluoroscopy time and total number cine frames for CA and PTCA procedures were recorded for each patient. Results: Mean ± SD of KAP in CA and PTCA were 33 Gy.cm2 ± 18.8 Gy.cm2 and 80.3 Gy.cm2 ± 65.6 Gy.cm2 respectively. The comparison showed that CA KAP (33Gy.cm 2 ), fluoroscopy time (2.7±2.4min), and cine frames number (571±149) except of on case, were lower than (P<0.001) the results of other studies and mean KAP due to PTCA procedures, except for three cases, were not significatly different from the other references’ results. Conclusion: The high level expert cardiologists couldn't have a significant effect on the decrease of patient dose since they should also teach angiography examinations to medicine students. With increasing patient BMI the value of KAP increased, but the fluoroscopy time and cineframes number did not change significantly. In addition, the results showed that the use of flat panel detector was not sufficient for decreasing patient dose, and system's adjustment was more important. Iran. J. Radiat. Res., 2008; 6 (4): 167­172

Effect of low dose gamma-radiation upon Newcastle disease virus antibody level in chicken

Abstract: Background: The specific antibody response against Newcastle disease virus (NDV) in the blood serum of chickens hatched from eggs exposed to low dose gamma-radiation was studied. Materials and methods: Two groups of eggs of commercial meat chicken lines were irradiated with the dose of 0.30 Gy 60 Co gamma-rays before incubation and on the 19 th day of incubation, respectively. The same number of eggs unexposed to gamma-radiation served as controls. After hatching the group of chicken hatched from eggs irradiated on the 19th day of incubation was not vaccinated while the group of chicken hatched from eggs irradiated before incubation was vaccinated on the 14 day. Specific serum anti-NDV antibodies were quantified by the hemagglutination inhibition assay with 4 HA units of NDV La Sota strain. Result: Specific antibody titres against NDV in the blood serum of chickens hatched from eggs irradiated before incubation and vaccinated on the 14th day significantly increased on the 28th day. Specific antibody titre against NDV in the blood serum of chickens hatched from eggs irradiated on the 19th day of incubation and non-vaccinated was significantly higher on the 1 st and 14 th day. Conclusion: Acute irradiation of heavy breeding chicken eggs with the dose of 0.30 Gy 60 Co gammarays before incubation and on the 19th day of incubation could have a stimulative effect on humoral immunity in chickens. Iran. J. Radiat. Res., 2009; 7 (1): 27­31

Measurement of 137Cs in soils of Tehran province

Abstract: Background: An amount of artificial radionuclide has been released into the environment as fallout, resulting from atmospheric nuclear weapon tests, nuclear accidents such as Chernobyl and together with air currents have polluted the world. Materials and Methods: 37 surface soil samples of Tehran province were collected in the period between June and September 2008, by implementing methods and standard instruments. The concentration of the artificial radionuclides (137Cs) in the soils of Tehran province were determined by gamma spectroscopy (HPGe), and the data were analyzed both quantitatively and qualitatively. The results have been compared with other radioactivity measurements. Results: The concentration of 137 Cs found in top soils (0-5 cm), in the depth of (12.5-17.5 cm) and in the depth of (27.5- 32.5 cm), ranged from 0.29-28.82 Bq.kg -1 , 0.3-19.81 Bq.kg -1 , 0.8-7.43 Bq.kg -1 , respectively. The total average of 137Cs activity, in the above depths was, 11.30, 4.87 and 1.8 Bq.kg-1, respectively. Conclusion: Considering the obtained results from high average values of 137Cs in Europe and its relation to Chernobyl accident, and the higher average concentration of 137 Cs in Tehran province, can also be attributed to Chernobyl accident due to the proximity of Iran to the place of the accident's occurrence. Iran. J. Radiat. Res., 2009; 7 (3): 141­149

Three different procedures in labeling of Ubiquicidin with technetium 99m: a comparative study

Abstract: *Corresponding author: Dr. M. Gandomkar, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran, Tehran, Iran. E-mail: msgandomkar@yahoo.com Background: UBI 29-41 (a derivative of antimicrobial peptide ubiquicidin) labelled with 99mTc is reported to discriminate between bacterial infections and sterile inflammatory processes. In this study, three lyophilized kit were performed, one of them based on the direct labelling with only SnCl2 as reducin g agen t , and o ther two based on 6 hydrazinopyridine-3-carboxylic acid (HYNIC) and tricine as a coligands with or without ethylenediamine -N,N’-diacetic acid (EDDA). Materials and Methods: Synthesis of UBI 29-41 was performed on solid phase using a standard Fmoc strategy. BOC-HYNIC was conjugated with peptide in solution. Three lyophilized kits were prepared as follows: kit 1: 40 μg UBI 29-41, 5 μg SnCl2, pH = 9; kit 2: 40 μg UBI 29-41, 40 μg SnCl2, 20 mg tricine, pH = 5.2; kit 3: 40 μg UBI 2941, 40 μg SnCl2, 15 mg tricine, 5 mg EDDA, pH = 7. With addition of 99mTcO4solution, kits were labeled under specific conditions, and the radiochemical purity was evaluated by ITLC and HPLC methods. Stability and protein binding in human serum followed by in vitro binding to bacteria were assessed. Biodistribution of radiopeptides in staphylococcus aureus infected rats muscles were studied using ex vivo counting and scintigraphy. Results: Radiochemical analysis indicated rapid and high labeling yield (>95%) for the three kits. Binding to bacteria for kit 2 was to some extent higher than that was obtained for the two other kits. Specific accumulation in infected thigh muscles, as indicated by T/NT ratios was 3.29, 4.6 and 3.77 for kit 1, 2 and 3, respectively. Conclusion: The HYNIC-UBI 29-41 labeled in presence of tricine as coligands (kit 2) showed the most promising results for further in vivo evaluation. Iran. J. Radiat. Res., 2009; 7 (2): 97­104

The role of Rad51 protein in radioresistance of spheroid model of DU145 prostate carcinoma cell line

Abstract: Background: Rad51 is a protein with critical role in double strand break repair. Down-regulation of this protein has a significant effect in radiosensitivity of some cell lines like prostate carcinoma. Compared to monolayer cell culture model, the spheroids are more resistant to radiation. The aim of the current study was to determine the Rad51 protein level in DU145 spheroids, and monolayer cells before and after exposure to gamma irradiation. Materials and Methods: In the present study, western blot was used to determine the level of Rad51 protein in DU145 cell line grown as monolayer and spheroid. Results: Western blot analysis showed that in the spheroid cells, Rad51 had an elevated level before and after radiation in comparison with monolayer cells. Higher doses of radiation induced elevated expression of Rad51 protein in both culture models. The level of at protein after exposure to gamma rays had been timedependent. Conclusion: Rad51 might act as a mediator of radiation resistance in tumor cells. Repression of Rad51 activity could be a prominent strategy to overcome radiation resistance of tumors. Iran. J. Radiat. Res., 2009; 7 (1): 19­25

Acquiring molecular interference functions of X-ray coherent scattering for breast tissues by combination of simulation and experimental methods

Abstract: Background: Recently, it has been indicated that X-ray coherent scatter from biological tissues can be used to access signature of tissue Some scientists are interested in studying this effect to get early detection of breast cancer Since experimental methods for optimization are time consuming and expensive, some scientists suggest using simulation Monte Carlo (MC) codes are the best option for radiation simulation; however, one permanent defect with MC codes has been the lack of a sufficient physical model for coherent (Rayleigh) scattering, including molecular interference effects Materials and Methods: It was decided to obtain molecular interference functions of coherent X-ray scattering for normal breast tissues by combination of modeling and experimental methods A Monte Carlo simulation program was written to simulate the angular distribution of scattered photons for the normal breast tissue samples Moreover, experimental diffraction patterns of these tissues were measured by means of energy dispersive X-ray diffraction (EDXRD) method The simulation and experimental data were used to obtain a tabulation of molecular interference functions for breast tissues Results: With this study a tabulation of molecular interference functions for normal breast tissues was prepared to facilitate the simulation diffraction patterns of the tissues without any experimental Conclusion: The method may lead to design new systems for early detection of breast cancer Iran J Radiat Res, 2009; 7 (2): 113­117

Solar ultraviolet-B radiation monitoring in Khorram Abad city in Iran

Abstract: Background: The increasing evidences show that global depletion of stratospheric ozone layer is caused by pollutant and growing incidence of the skin cancer and cataract is related to the amounts of solar UV radiation reaching the earth׳s surface. Therefore, the main driving force behind such efforts has been the lack of an appropriate network in scope monitoring of the terrestrial UV radiation. Materials and Methods: The present work was performed at Khorram Abad province, Lorestan, Iran. Khorram Abad (48˚, 21΄ E and 30˚, 23΄ N) is approximately 1171m above the mean sea level. UV radiation was measured using a UV-Biometer Model 501, from November 2005 till November 2006. Results: Hourly average UV- index, the effective power and other parameters such as effective UV dose have been "moderate" from April until the end of August 2006 and very low from November till January 2006. However, in some days, the maximum UVI was in the range of "High" , especially in May. Conclusion: It was observed that the monthly average hourly UV index values in Khorram Abad were never at the extreme range. Chronic UVB exposure could be the major cause of eye's and skin disease in months from April to August, during which most people's activities were performed outdoor in the province of Lorestan. Iran. J. Radiat. Res., 2009; 7 (3): 171­175

Radioresponse of human lymphocytes pretreated with boron and gadolinium as assessed by the comet assay

Abstract: Background: Boron and gadolinium are among the nuclides that hold a unique property of being a neutron capture therapy agent. Neutron beams have often a considerable portion of gamma rays with fast neutrons. Gamma rays, as beam contaminants, can cause considerable damage to normal tissues even if such tissues do contain high boron concentrations. Materials and Methods: The modification of radioresponse in human lymphocytes pretreated with boron or gadolinium compound was studied by assessing the DNA damage using single cell gel electrophoresis (SCGE), the comet assay. The lymphocytes from the human peripheral blood were irradiated with 0, 1, 2 and 4 Gy of gamma rays from a 60 Co isotopic source with or without pretreatment of boron or gadolinium compound for 10 minutes at 4�( . Post-irradiation procedures included slide preparation, cell-lysing, unwinding and electrophoresis, neutralization, staining, and analytic steps, gel electrophoresis. Results: The results indicate that pretreatment with boron compound (50 nM or 250 nM of 10B) is effective in reducing the radiosensitivity of the lymphocyte DNA. Conversely, pretreatment with gadolinium compound (50 nM) led to a dose-dependent increase in the radiosensitivity, most prominently with a dose of 4 Gy (P<0.001). Furthermore, when the lymphocytes were pretreated with a combined mixture (1:1) of boron (250 nM) and gadolinium (50 nM) compounds, the reduced radiosensitivity was also observed. Iran. J. Radiat. Res., 2009; 7 (2): 63­68

Micro-pixe analysis in invasive ductal carcinoma tissues after treatment of astaxanthin

Abstract: Background: Trace elements play an important role in a number of biological processes. Astaxanthin (ASX), a carotoid pigment found in certain marine plant and animals, has shown anti cancer and anti free radical properties. This work intended to understand the effect of Astaxanthin in breast cancer (invasive ductal carcinoma, IDC) by using micro-pixe method. For this aim the concentration of trace elements were compared in healthy, cancerous and cancer treated with astaxanthin in the breast and liver tissues of breast cancer bearing mice, using proton induced X-ray emission (PIXE). Materials and Methods: Proton induced X-ray emission (PIXE) was used in a study intending to compare the concentration of trace elements in breast and liver tissues of mice bearing tumor, three groups of mice: healthy, cancerous, and cancerous treated by astaxanthin, were considered. Astaxanthin was supplied from Research Institute of women, Alzahra University. Results: Comparing the untreated tumor tissue, treatment with Astaxanthin significantly decreased the amount Fe, P, S, and Ca elements level in tumor tissue of the breast cancer. It is also found that the concentrations of those elements in liver of the untreated mice and the liver of treated mice with astaxanthin were fairly equal. Astaxanthin significantly decrease the accumulation of elements in the site of tumor, and caused the breast cancer cell membrane to lose their desire to collect the elements from healthy tissues. Conclusion: The micro -pixe technique could calculate elemental concentrations in tissues. Changes in metallic elements may affect microenvironment and cell functions, which might led lead to cell degeneration or death, the results shows that astaxanthin reduces vital element concentration in tumor site, thus it could be used as an anti tumor agent. Iran. J. Radiat. Res., 2009; 7 (1): 33­39

Induction of micronuclei in a transplantable murine tumor after multimodality treatment with cis-platin, radiation and hyperthermia

Abstract: Background: Tumor response after multimodality treatment using combination of radiation, chemotherapeutic drugs and hyperthermia usually assessed by parameters such as tumor growth delay, volume doubling time and regression response. The study herein was conducted to investigate the usefulness of micronucleus assay for assessing the multimodality treatment. Materials and Methods: The induction of micronuclei (MN) in a transplantable solid tumor grown in inbred Balb/c mice was analyzed after treating the tumors with cis-platin (cDDP), radiation (RT) and hyperthermia (HT). Results: The MN frequency in tumor was measured at 1, 3, 5 and 7 days of post-treatment. On day 1, all the cDDP and RT groups, except HT treatment produced significantly higher MN counts from that of the untreated tumors. Cis-platin treatment resulted in a dose-dependent linear increase in the frequency of MN induction on day one. Combination of radiation with cDDP or HT, as bimodality treatment further increased the MN counts. In the tri-modality group (cDDP+RT+HT) the MN counts were not significantly higher than the bi -modality treatments, however there was an immediate tumor shrinkage indicating the contribution of other forms of cell death. Although, MN counts were declined after day five post-treatment, remained significantly higher than the control on day seven-post treatment in hyperthermia alone or its combination with RT and RT+ cDDP groups. Conclusion: Micronucleus assay may be useful for assessing the post-treatment regression response of resistant tumors, while monitoring the response of sensitive tumors the parameters such as apoptosis and necrosis may also contribute considerably to tumor cell loss contributing immediate tumor regression.

Preparation and quality control of radiolabeled streptokinase for Thrombosis imaging

Abstract: Background: In order to diagnose the site of thrombi, radiolabeled streptokinase can be prepared. The radiolabeled compound can be used in imaging of thrombi in many cardiovascular diseases. Materials and Methods: Streptokinase was successively labeled with [67Ga]-gallium chloride using cyclic DTPA-dianhydride. The conjugation with DTPA was optimized for concentration, time and temperature followed by size exclusion chromatography using G-50 Sephadex. The radiochemical purity of the tracer was checked using HPLC and ITLC methods. The biodistribution studies were performed in normal rats up to 167 h using tissue counting and preliminary SPECT studies up to 2 h. Results: The radiolabeled enzyme was prepared in 60 minutes after incubation at room temperature, with the radiochemical purity of >95% (HPLC) and >99% (ITLC) methods. The radioactivity was accumulated in lung, intestine and liver as shown by scarification and SPECT (Single Photon Emission Computed Tomography) methods. Conclusion: Radiolabeled Streptokinase was prepared in suitable radiochemical purity and its biodistribution is comparable to other radiolabeled proteins. Further studies are required to investigate the imaging properties of the tracer in appropriate animal model. Iran. J. Radiat. Res., 2009; 6 (4): 195­ 200

Construction of a dose - response curve by induction of premature chromosome condensation for biological dosimetry

Abstract: *Corresponding author: Mr. Aziz Mahmoudzadeh Emamchai, Novin Medical Radiation Institute, Tehran, Iran. Fax: +98 21 88086782 E-mail: mehdi_53@email.com Premature Chromosome Condensation (PCC) appears to have a possible utility for biological dosimetry purposes. The PCC technique may be adapted for cases of suspicion of overexposure where sampling is performed at least one day after an accident. For this purpose, human blood samples were exposed in vitro to 60Co up to 10 Gy and the PCC technique was performed immediately after irradiation. Analysis of excess PCC fragments distribution showed an over dispersion and the doseeffect relationship was best characterized by linear regression. Iran. J. Radiat. Res., 2009; 6 (4): 213­218

Preparation and Biodistribution of [67Ga]-labeled- oxytocin for SPECT purposes

Abstract: Background Oxytocin (OT) is a paracrine hormone with various biological activities and many sex organs in both sexes, as well as many tumor cells have shown to have related receptors. In this study the development of a receptor imaging tracer for possible tumor imaging has been described. Materials And Methods OT was successively labeled with [67Ga]-gallium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 ml of a OT pharmaceutical solution (2 mg/ml, in phosphate buffer, pH=8) to a glass tube pre-coated with DTPA-dianhydride (0.02 mg) at 25°C with continuous mild stirring for 30 min. Radiochemical purity (RCP) of the labeled compound was determined, using RTLC and ITLC followed by stability tests and animal biodistribution studies. Results Radiolabeling took about 60 minutes with a RCP higher than 98 % at optimized conditions (specific activity = 1000 Ci/mM, labeling efficiency 80%). The stability of the tracer at room temperature was significant, up to an hour. Preliminary in vivo studies in normal female rat model showed ovary/blood and ovary/muscle ratio uptake of the tracer in 60 minutes to be 4.53 and 9.18, respectively. The result was consistent with the reported OT receptor distribution in normal female mammals. Conclusion The radiolabeled oxytocin, prepared in this study, was a possible fast acting tracer for OT receptor imaging; studies however, more studies are required to determine the best imaging conditions especially in larger mammal animals.

YCF and YAP gene expressions in yeast cells after irradiation combined with mercury treatment

Abstract: Background: All aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species (ROS). These are highly reactive and capable of damaging cellular constituents such as DNA, lipids and proteins. Consequently, cells from many different organisms have evolved mechanisms to protect their components against ROS. It is known to have some genes for resistance to heavy metals and ionizing radiation (IR). Materials and Methods: Saccharomyces cerevisiae is an ideal model organism for deducing biological processes in human cells. In this work, cell viability and gene expression was investigated in yeasts treated with IR, HgCl2, and IR combined with HgCl2. Cell viability was measured by colony forming unit (CFU) method in an YPD medium. Gene expression was analyzed by the Real-time PCR. Results: The viability was lower at the higher dose. At a dose above a certain level, the viability came down to zero. The combined treatment decreased the viability, as well. Metal resistance genes were expressed in the cells treated with HgCl2. In a similar way, irradiation also triggered the expression of some radiation resistance genes. YCF and YAP genes were induced consecutively with the HgCl2 concentration, and also with a higher total dose under a lower dose rate condition. These two genes were, however, expressed differently under the 0.2 mM HgCl2 treatment condition. In the cells treated with 0.1-0.2 mM HgCl2, the viability was higher than with any other concentrations. Conclusion: The results demonstrated that the higher dose induced more expression of oxidative stress resistance genes related to cell survival mechanism. Combined treatment of radiation with mercury chloride resulted in synergistic effects leading to a higher expression of the genes than treatment of a single stressor alone. Iran. J. Radiat. Res., 2009; 6 (4): 161­166

Synthesis and radioprotective study of novel amino-alkyldithiocarbamic acid derivatives against γ-irradiation in mice

Abstract: Background: The aim of this study was to evaluate the radioprotective capacity of some novel aminoalkylated dithiocarbamic acid potassium salts against γ-irradiation in mice. Materials and Methods: Eight compounds containing 2-aminoethyl-, 3aminopropyl-, 4-aminobutyl-, 5-aminopentyl-, 6aminohexyl-, 7-aminoheptyl-, 8-aminooctyl and 9aminononyl of dithiocarbamate derivatives were prepared. Male NMRI mice were injected intraperitoneally (IP) with a geometric progression of doses (300 -1000 mg/kg), through the dose response range for lethal toxicity. To evaluate the radioprotecive activity, one-half of the toxic LD50 of each compound were injected IP to groups of twenty mice, 30 minutes prior to γ-irradiation. The treated animals were kept for 30 days, and the lethality was recorded each day. Results: Among Eight compounds of alkyl dithiocarbamic acid derivatives, 5-aminopentyl, 7-aminoheptyl, 8-aminooctyl and 9-aminononyl dithiocarbamic acid mono potassium salts are new compounds. All evaluated compounds showed a concentrationdependent effect on the survival in mice. The LD50 values were found to be more than 599 mg/kg. The percentages of 30-day survival of mice for 2aminoethyl, 7-aminoheptyl and 8-aminooctyl dithiocarbamic acid derivatives were 7%, 40% and 13.5%, respectively, when injected 30 minutes before γirradiation. Other compounds had no radioprotective effects. Statistical analysis showed a significant difference between the treated and control groups for the 7-aminoheptyl derivative (p<0.05). Conclusion: Among the compounds investigated in this study, 7aminoheptyl dithiocarbamate derivative showed more radioprotective effects in comparison with the others. Although it seems that the radioprotective effects in these derivatives correlate with the size of the alkyl chain, more experiments are required to support this hypothesis. Iran. J. Radiat. Res., 2009; 7 (2): 91­96