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Background: A powerful and improved technique, Proton Induced X-ray Emission (PIXE) has been performed-yielding the elemental composition of 17 samples of surgically excised malignant and normal tumors of breast tissue. The samples without any further process as thick targets were put on capton foil backing. There are no homogenizing processes. The PIXE spectra analysis was performed using he non-linear least square fitting code AXIL and GUPIX.

Materials and Methods: The samples are taken from patients in the wide range of age and are bombarded by 2.0 Me v energy proton beams produced by van de graff accelerator in vacuum. The quantitative comparison between two types of tissues was evaluated by assessing the presence of c alcium, Potassium, Iron, Copper and Zinc, as minor and trace elements.

Results: Results in this study indicate that relative values of Cu / Zn, P / K and also Ca and S in benign type were higher than those in malignant type, but the concentration of Fe and Zn in cancerous tissues was significantly higher than those for benign type.

Conclusion: Results suggest significant elevation of Zinc in the pathological tissues. Cu/Zn ratio for both type of tissues are evaluated. The results show that this ratio in patients with breast cancer is significantly lower than the normal group. Selenium and Arsenic was not obtained in any of 17 samples. Most of the tissues of benign kind (Fibrocystic and Fibro adenoma) contain Cadmium. Calcium concentration in normal tissues is significantly higher than tumorous tissues. Iran . J. Radiat. Res., 2003 1(1): 23 - 27.

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Background: From the time immemorial man has been exposed to ionizing radiation from the environment in which he lives. Radiation protection concepts and philosophy have been evolving over the past several decades. Materials and Methods: The radioprotective of effect of Aloe vera leaf extract (1000 mg /kg b.wt. orally for 15 consecutive days) has been studied against 6 Gy of gamma radiation in the intestine of Swiss albino mice at various post - irradiation intervals viz. 12 hrs, 24 hrs. and 3, 5, 10, 20 and 30 days. Results: Crypt survival, villus length, apoptic cells, mitotic figures and goblet cells in jejunum were studied after irradiation. Irradiaton produced a significant decrease in crypt survival, mitotic figures and villus length whereas goblet and apoptic cells showed a significant increase from sham irradiated animals. The major changes were observed on day 3 after irradiation. AVE pre-treated irradiated animals resulted in a significant increase in the number of crypt cells, mitotic figures and villus length whereas the counts of apoptic and goblet cells showed a significant decrease from respective control group at all the autopsy intervals. Irradiated animals resulted in the elevation in lipid peroxidation and a reduction in glutathione acitivity. On contrary, AVE treatment before irradiation caused a significant depletion in lipid peroxidation and elevation in glutathione activity. Conclusion: The present study suggests the possible radioprotective ability of Aloe vera leaf extract.

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Background: Total Body Irradiation (TBI) is different from standard radiotherapy in many aspects, so it is not easy to predict the delivered dose to the patient under TBI treatment. Diode dosimetry procedures for surface dose reading can help to define variations of the actually delivered dose from the prescribed one. The aim of this study was to describe the measurements made to calibrate diodes in order to implement as a dosimeter for TBI tratment. An algorithm was also proposed based on diode dosimetry in order to determine the midplane dose. Materials and Methods: In this study, four p-type diodes connected to a MULTIDOSE electrometer were implemented as dosimeter. For diode calibration a water phantom with dimension of 30×30×32cm3 along with a 0.6 cc Farmer ion chamber were used. Directional dependence of diodes, the effects of thickness correction factor and complete backscatter factor were studied. Three algorithms, arithmetic, geometric mean and proposed algorithm were used to investigate midplane dose determination in TBI condition. Results: It was found by measurements that the effect of angle incident on diode response was significant and should have been taken into account. Variation in thickness correction factor was found about 0.7%. The accuracy in midplane dose determination in the arithmetic, geometric mean and proposed algorithm was about 3.8, 12.5 and 3.3%, respectively. Conclusion: Diode dosimetry is very useful as a check of midplane dose delivered to patients under TBI treatment. When the calibration and correction factors are carefully determined, high precision can be obtained. The proposed algorithm by this study seems to be useful in order to midplane dose determination in TBI condition. Iran. J. Radiat. Res., 2008 6 (1): 43-50

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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

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Background: Natural radiation is constantly present in the environment and is emitted from a variety of natural and artificial sources. It affects human body and environment. Materials and Methods: The activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K have been determined by Gamma ray spectrometer with an HPGe detector in sediments of Cauvery River, Tamilnadu, India. Results: The absorbed dose rate, radium equivalent concentration, external (Hex) and internal (Hin) hazardous indices are calculated from criteria formula and compared with the international recommended limits. The radioactive heat production rate and activity concentration index are also calculated. The observed dose rate measurements from ERDM (Environmental Radiation Dosi Meter) at 1m above the ground level at each site of the both rivers are measured and correlated with calculated absorbed dose rate. Conclusion: From the various parameters and correlation between them, the Cauvery River does not pose a radiological hazard except the site no. 21, 22, 23, 30, 31 and 35. Iran. J. Radiat. Res., 2011 8(4): 211-222

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Background: Breakfast cereal is a nutritious type of food that is widely consumed by various age groups in Kuwait. This study investigates the presence of long-lived gamma emitters in breakfast cereal, and estimates annual effective doses to various age groups. Materials and Methods: Breakfast cereal samples were collected from the Kuwaiti local market. The samples originated from different countries. After proper lab treatment, the samples underwent gamma spectroscopy, where the targeted radionuclides were ²²⁶Ra, ²³²Th, and ⁴⁰K. Results: While ⁴⁰K was detected in all samples, ²²⁶Ra and ²³²Th were detected in most samples. The activity concentration of each targeted radionuclide varied from one sample to another. The annual effective dose from consumption of breakfast cereal is estimated to be 129, 185, and 351 μSv for the adult, child, and infant age groups respectively. Conclusion: The obtained activity concentrations are found to agree with those reported in the literature. Moreover, the estimated annual effective doses are found to be safe. Iran. J. Radiat. Res., 2012 10(3‐4): 117‐122

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Background: Identify the optimal technique of radiotherapy for patients with high grade glioma. Our initial year of experience with RapidArc radiation therapy. Materials and Methods: Planning CT scans of 50 patients with grade IV glioma were reviewed and three plan sets by 3D Conformal Radiotherapy (3DCRT), Intensity Modulated Radiotherapy (IMRT) and Rapid Arc (RA) were generated and the plans were compared. Results: Planning target Volume (PTV) coverage is comparable. However IMRT and RA give better sparing of critical structures. Treatment time and Monitor Units (MU) for Rapid Arc is much less compared to IMRT. Conclusion: If PTV is near to the Organs at Risk (OAR), then IMRT gives good result in comparison to 3DCRT plans. Rapid Arc is faster than IMRT and 3DCRT for same dose prescription to PTV and constraints of OAR.

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Background: Physical wedges are still widely used as beam modifiers in external beam radiotherapy. However the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. The aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value layer, mean energy and tissue–phantom ratio. Materials and Methods: The effect of physical wedges on the photon beam quality of a 6-18MV Varian 2100C/D accelerator was studied with the BEAMnrc Monte Carlo code. Good agreements were obtained between measured and calculated depth doses and beam profiles for open and wedged photon beams at both energies. Results: It was noticed that for 6 MV photon beams, physical wedges have more significant effects on beam quality than for 18 MV. Also it was obtained that at 18 MV photon beam as the wedge angle increased, the effect of wedge on beam quality becomes reversed and beam softening occurred. Conclusion: According to these results, it is recommended that beam hardening and softening of physical wedges should be considered in treatment planning systems in order to increase the accuracy in dose delivery.

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Background: The therapeutic administration of ¹³¹I for thyroid remnant ablation and for metastases comes up with some adverse effects. This study was conducted to investigate whether single high dose radioiodine therapy affects lacrimal gland functions or not. Materials and Methods: Seventy-eight eyes of 39 patients, who were diagnosed as differentiated thyroid carcinoma, were objectively tested with Schiermer’s test and tear film break-up time test before and 1 and 6 months after high dose (&ge 3700 MBq) ¹³¹I therapy. Results: The median values of pre-treatment Schiermer’s test were 10.00 mm and 9.60 mm for right and left eyes, respectively. At the post-treatment first and sixth months, no significant change was observed in the median values of Schiermer’s test in both eyes (p= 0.189 and p=0.085, respectively, Friedman test). The median values of pre-treatment tear film break-up time test were 9.15 sn and 9.20 sn for right and left eyes, respectively. The median values of post-treatment tear film break-up times reduced at first and sixth months and the difference between the pre-treatment and post-treatment values were significant in both eyes (p=0.020 and p=0.022 for right and left eyes, respectively, Friedman test). Conclusion: Impairment of goblet cell function occurs early after administration of single high dose ¹³¹I application. However, reduction in tear secretion from lacrimal gland is not observed.

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Background:  This study presents patient specific and organ dose estimation in computed tomography (CT) imaging of thorax directly from patient CT image using Monte Carlo simulation.  Patient's CT image is considered as the patient specific phantom and the best representative of patient physical index in order to calculate specific organ dose. Materials and Methods: EGSnrc /BEAMnrc Monte Carlo (MC) System was used for CT scanner simulation and DOSXYZnrc was used in order to produce patient specific phantom and irradiation of photons to phantom in step and shoot mode (axial mode). In order to calculate patient thorax organ dose, patient CT image of thorax as voxelized phantom was divided to a 64x64x20 matrix and 6.25 x 6.25 x 6.25 mm³ voxel size and this phantom was imported to DOSXYZnrc code. MC results in unit of Gy/particle were converted to absorbed dose in unit of mGy by a conversion factor (CF). We calculated patient thorax organ dose in MC simulation from all irradiated slices, in 120 kV and 80 kV photon energies. Results: Effective dose was obtained from organ dose and organ weighting factor. Esophagus and spinal cord received the lowest, and bone received the highest dose. In our study, effective dose in CT of thorax was 7.4 mSV and 1.8 mSv in 120 and 80 kV, respectively. Conclusion: The results of this study might be used to provide the actual patient organ dose in CT imaging and calculation of real effective dose based on organ dose.