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Showing 41 results for Ge
S. Vatankhah, K. Moosavi, J. Salimi, L. Geranpayeh, H. Peyrovani, Volume 1, Issue 1 (6-2003)
Abstract
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.
Dr. P. Gehlot, Dr. P.k. Goyal, Volume 5, Issue 2 (9-2007)
Abstract
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.
Dr. M. Allahverdi, Gh. Geraily, M. Esfehani, A. Sharafi, A. Shirazi, Volume 6, Issue 1 (6-2008)
Abstract
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
L.a. Sathish, K. Nagaraja, H.c. Ramanna, V. Nagesh, S. Sundareshan, Volume 7, Issue 1 (6-2009)
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
Dr. S. Murugesan, S. Mullainathan, V. Ramasamy, V. Meenakshisundaram, Volume 8, Issue 4 (3-2011)
Abstract
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
Dr. T. Alrefae, T.n. Nageswaran, T. Al-Shemali, Volume 10, Issue 3 (12-2012)
Abstract
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
Dr. B. Goswami, S. Mitra, S. Banerjee, A. Shiva B, P. Nagendran, P. Kumari, P. Goswami, A. Chakraborty, S. Mukherjee, Volume 11, Issue 4 (10-2013)
Abstract
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.
Gh. Geraily, M. Mirzapour, Dr. S.r. Mahdavi, M. Allahverdi, A. Mostaar, M. Masoudifar, Volume 12, Issue 3 (7-2014)
Abstract
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.
Dr. G.k. Gedik, S. Gedik, B.e. Koktekir, L. Kebapcilar, P.o. Kara, Volume 12, Issue 4 (10-2014)
Abstract
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.
Gh.r. Fallah Mohammadi1, Dr. N. Riyahi Alam, Gh. Geraily, R. Paydar, Volume 14, Issue 4 (10-2016)
Abstract
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.
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