@article{ author = {Ramachandran, T.V.}, title = {Environmental thoron (220Rn) : A review}, abstract ={Ever since studies on uranium miners established the presence of a positive risk coefficient for the occurrence of lung cancer in miners exposed to elevated levels of 222Rn and its progeny, there was a great upsurge of interest in the measurement of 222Rn in the environment and considerable data is generated on the levels of 222Rn in the environment across the worlds and is periodically reported by UNSCEAR. In contrast to this, data pertaining to 220Rn in indoors and workplace environment is scare due to the general perception that its levels are negligible due to its shorter half life, and subsequently its contribution to the total inhalation dose is ignored, in the presence of other significant sources of natural radiation. Many locations have higher levels of natural background radiation due to elevated levels of primordial radio-nuclides in the soil and their decay products like radon (222Rn), and thoron (220Rn) in the environment. It is estimated inhalation of 222Rn, 220Rn and their short lived progenies contribute more than 54 % of the total natural background radiation dose received by the general population. This component is not adequately estimated for any country so far on a national level. 220Rn problem will also be a problem in industries which uses thorium nitrate. Including India, lamps using throated gas mantles are being still used for indoor and outdoor lighting and hawkers in rural as well as urban areas. Considering the fact that large amount of thorium nitrate is being handled by these industries, contribution to the inhalation dose of workers from 220Rn gas emanated and build up of the progeny in ambient air may also be quite significant. In this article current status of 220Rn levels in the indoor environment and workplaces as well as in other industries where large amount of 232Th is being handled, is being summarized. Iran. J. Radiat. Res., 2010 8 (3): 129-147}, Keywords = {Background radiation, radon, thoron, inhalation dose.}, volume = {8}, Number = {3}, pages = {129-147}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-644-en.html}, eprint = {http://ijrr.com/article-1-644-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Sivakumar, R.}, title = {A study on radon and thoron progeny levels in dwellings in South India}, abstract ={Background: Decay products of radon and thoron present in indoor environment are the most important sources of radiation from natural sources which affect human beings, since general public spend at lest 80% of their time in indoor. Materials and Methods: Air samples were collected for measuring the concentration of radon and thoron daughter products from various indoor environments during four different seasons of the year from the Gudalore taluk of Nilgiri Biosphere using high volume air sampler. The concentration of decay products of radon and thoron were estimated using an alpha counter. Results: Studies have revealed that the annual average potential alpha energy concentrations of radon and thoron progeny in dwellings of Gudalore were recorded as 3.54 and 2.65 mWL respectively. It was also observed that the potential alpha energy concentration (PAEC) values for radon progeny undergo dramatic change with the change of season perhaps due to different aerosol contents in the air. The maximum 222Rn (3.93 mWL) and 220Rn (3.10 mWL) progeny concentrations were observed during winter months and the minimum values (222Rn 3.14 mWL and 220Rn 2.20 mWL) were observed during summer. Conclusion: Studies have shown that the dwelling with mud wall registered high value of radon and thoron progenies (5.49 mWL and 3.88 mWL). While low values were observed in dwellings with vinyl floor. High concentrations of radon and thoron progeny were observed between 3.00 to 5.00 Hrs, while low values were observed at 14.00 hrs. Studies suggest that radiation emission from radon and thoron daughter in the study area were remained well below the recommended level. Iran. J. Radiat. Res., 2010 8 (3): 149-154}, Keywords = {Radon, thron, progeny, seasonal variation, diurnal variation etc.}, volume = {8}, Number = {3}, pages = {149-154}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-645-en.html}, eprint = {http://ijrr.com/article-1-645-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Tavakoli, M.B. and Monsef, S. and Hashemi, M. and Emami, H.}, title = {Assessment of patients skin dose undergoing coronary angiography and Percutaneous Transluminal Coronary Angioplasty (PTCA)}, abstract ={Background: Practice of interventional cardiology procedures such as Coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) has largely increased in recent years and is now changing to a matter of routine in many hospitals. The purpose of this study was to measure skin and organ doses in patients undergoing CA and PTCA and to find a probable relation with cardiologist's work experience. Materials and Methods: A group of 57 patients who were admitted to Nour and Chamran hospitals, Isfahan, Iran, either for CA (n=37) or PTCA (n=20) was checked for skin, eyes and thyroid gland radiation dose. Skin dose measurement was carried out with thermoluminescent dosimeters (TLD-100) placed at three different positions on the patients' bodies. Also the thyroid and eye doses were measured using the same procedure. Results: Mean median, standard deviation and maximum doses for these results are presented. Maximum values found for skin in CA, PTCA, thyroid gland and eyes were 41.00, 73.90, 3.10 and 1.43 cGy, respectively. Average exposure time for CA and PTCA was 4.2±2.6 and 10.8±8.2 minutes, respectively. Radiation dose to the critical areas in each procedure in addition to its relation to the type of procedure was studied. Correlation between maximum skin dose and cardiologists' work experience was also investigated. Conclusion: 85% of the cases in CA and 78% of cases in PTCA received maximum skin dose of lower than 25cGy well below the threshold of 2 Gy suggestions for transient erythema. Iran. J. Radiat. Res., 2010 8 (3): 155-160}, Keywords = {Coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA), skin dose, work experience, TLD.}, volume = {8}, Number = {3}, pages = {155-160}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-646-en.html}, eprint = {http://ijrr.com/article-1-646-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Bouzarjomehri, F. and Tsapaki, V.}, title = {Evaluation of cancer risk of the patients undergoing coronary angiography in Yazd, Iran}, abstract ={Background: Coronary angiography is a commonly performed diagnostic procedure with life saving benefits for the patient. However, this procedure involves relatively high radiation dose. The purpose of this study was to determine the average effective dose of patients undergoing coronary angiography and to estimate the associated radiation risk in terms of fatal malignancy. Materials and Methods: Radiation doses received by 103 patients who underwent coronary angiography (CA) at one hospital of Yazd province in Iran were measured in terms of Kerma Area Product (KAP). KAP values were then used to determine the effective dose and the organ doses using the NRPB-S262 conversion factors and to estimate the radiation cancer risk based on the population averaged probability coefficients given in ICRP-60 and BEIR-VII report. Results: A mean KAP value was found to be 29.15 ± 16.97Gy.cm2 and the estimated mean values of effective dose was 5.0 ± 3.18mSv. The dose of lung, esophagus, bone marrow, skin, stomach and female breast were 24.99±14.93 mSv, 14.01±9.47 mSv, 3.72±2.61 mSv, 2.9±1.8 mSv, 2.17±1.62 mSv and 1.46±0.32 mSv, respectively. The estimated total annual collective dose and caput dose were 17.52 man-Sv and 0.018mSv respectively. The frequency of examinations per 1000 population in Yazd was 3.5 which is lower than UK and the health care level I countries. Taking into account the ICRP risk factors, radiation dose arising from CA examinations could lead to 239 fatal cancers per million cases. Conclusion: Although the mean values of effective dose found in this study was lower than most of the published results, however CA examinations should be justified. Iran. J. Radiat. Res., 2010 8 (3): 161-167}, Keywords = {Coronary angiography, Kerma-area product, effective dose, radiation risk.}, volume = {8}, Number = {3}, pages = {161-167}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-647-en.html}, eprint = {http://ijrr.com/article-1-647-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Gupta, U. and Chaudhary, R. and Goyal, P.K.}, title = {Post-treatment effects of Alstonia scholaris extract against radiation-induced biochemical alterations in Swiss albino mice}, abstract ={Background: This study has been undertaken to find out the possible radioprotective potential of the Alstonia scholaris extract (ASE). Materials and Methods: For experimental study, healthy Swiss albino male mice were selected from an inbred colony and divided in four groups. Group I (normal) did not receive any treatment. Group II was orally supplemented ASE once daily at the dose of 100 mg/ kg.b.wt/day for 5 consecutive days. Group III (control) received distilled water orally equivalent to ASE for 5 days then exposed to 7.5 Gy of gamma radiation. Group IV (experimental) was administered orally ASE for 5 consecutive days once daily and exposed to single dose of 7.5 Gy of gamma radiation. Mice were sacrificed at different autopsy intervals viz. 12 hrs. 1, 3,7,15 and 30 days, and their liver and blood were taken for various biochemical estimations viz. lipid peroxidation (LPO), reduced glutathione (GSH), protein and cholesterol. Results: Radiation induced augmentation in lipid peroxidation and cholesterol was significantly ameliorated by ASE extract and deficit produced in protein and glutathione content by radiation was checked. Conclusion: Alstonia scholaris extract pretreatment hence renders protection against radiation-induced biochemical alterations in mice. Iran. J. Radiat. Res., 2010 8 (3): 169-177}, Keywords = {Alstonia scholaris, gutathione, lipid peroxidation, radioprotection, mice.}, volume = {8}, Number = {3}, pages = {169-177}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-648-en.html}, eprint = {http://ijrr.com/article-1-648-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Arya, S. and Sharma, J.}, title = {Modulation of radiation induced changes in nucleic acid content of liver of Swiss albino mouse by Tinospora cordifolia (Miers)}, abstract ={Background: Radiotherapy is the main modality of cancer treatment. There are many chemical radioprotectors which unfortunately have lethal or toxic effect. Therefore the search is on to find out natural plant based radioprotectors. A well known medicinal plant,which is more acceptable to the body, Tinospora cordifolia, was tested in animal tissues against gamma radiations. Radioprotective effects of Tinospora cordifolia (Miers) extract against radiation induced biochemical changes in liver of Swiss albino mouse were investigated. Materials and Methods: For experimental study, healthy swiss albino mice were selected from an inbred colony and divided into six groups and exposed to 6Gy and 8Gygamma radiation (control) or 6Gy and 8Gy gamma radiation with 5mg/ kg body weight of TC extract (experimental), sham irradiated (Normal) and plant extract only. Mice were sacrificed at various post irradiation intervals and liver was removed for quantitative estimation of DNA and RNA. Results: On the first day post irradiation in control group (6Gy and 8Gy both). DNA content decreased significantly as compared to the sham irradiated controls. Then there was continuous increase uptill 28th day but it remained below the normal. Decrease in DNA content of liver in the experimental group (6Gy) was observed on 1st day but the values were higher than that of the controls. RNA content increased in the control animals treated with 6Gy and 8Gy which was maximum at day 3, followed by a decrease at the subsequent intervals. Increase in the amount of RNA was recorded in the experimental animals also. Then came down to the normal on 10th day in the experimental groups (P<0.01). Conclusion: These results indicate that TC is able to protect nucleic acids the liver of Swiss albino mouse against gamma radiation. Iran. J. Radiat. Res., 2010 8 (3): 179-185}, Keywords = {Radioprotection, tinospora cordifolia, liver, DNA, RNA.}, volume = {8}, Number = {3}, pages = {179-185}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-649-en.html}, eprint = {http://ijrr.com/article-1-649-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Ghiasi, H. and Mesbahi, A.}, title = {Monte Carlo characterization of photoneutrons in the radiation therapy with high energy photons: a Comparison between simplified and full Monte Carlo models}, abstract ={Background: The characteristics of secondary neutrons in a high energy radiation therapy room were studied using the MCNPX Monte Carlo (MC) code. Materials and Methods: Two MC models including a model with full description of head components and a simplified model used in previous studies were implemented for MC simulations. Results: Results showed 4-53% difference between full and with the simplified model in the neutron fluence calculation. Additionally, in full MC model, increase in the field size decreased the neutron fluence but for simplified model, increase in the field size led to increase in neutron fluence. In calculating the neutron and capture gamma ray dose equivalent, simplified model overestimated (9-47%) and (20-61%) respectively in comparison to the full simulated model. However, a close agreement was seen between two models, for field size of 10×10 cm2. Conclusion: for MC modeling of photoneutrons and capture gamma in radiotherapy rooms, the detailed modeling of linac head instead of simplified model is recommended. Iran. J. Radiat. Res., 2010 8 (3): 187-193}, Keywords = {Photoneutron, capture gamma rays, Monte Carlo simulation, Linac head modeling.}, volume = {8}, Number = {3}, pages = {187-193}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-650-en.html}, eprint = {http://ijrr.com/article-1-650-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} } @article{ author = {Solimanian, A. and Ghafoori, M.}, title = {Standard calibration of ionization chambers used in radiation therapy dosimetry and evaluation of uncertainties}, abstract ={Background: Absolute dosimetry of external beam radiotherapy is carried out by the use of ionization chambers. These chambers must be calibrated at a standard dosimetry laboratory before any use in clinical dosimetry. The secondary standard dosimetry laboratory of Iran (SSDL) has the duty of calibrating the ionization chambers used in radiotherapy centers in Iran. Materials and Methods: The present work has described traceability of SSDL radiation measurement standards to relevant international standards, and calibration of therapy level ionization chambers in terms of air kerma and absorbed dose to water against 60Co gamma radiation, as well as uncertainty evaluation of calibration coefficients. Results: The expanded uncertainties in the determination of air kerma and absorbed dose to water are estimated to be 2% and 2.3% at approximately 95% confidence level, respectively. Conclusion: In order to maintain the requirement of ±5% accuracy in the dose delivery, the combined standard uncertainty of the other factors in the dose delivery i.e., dose measurement set-up, dose calculations, treatment planning, patient set-up, etc, should be less than 2.3%. Iran. J. Radiat. Res., 2010 8 (3): 195-199}, Keywords = {Dosimetry, ionization chamber, calibration, uncertainty.}, volume = {8}, Number = {3}, pages = {195-199}, publisher = {Dr. Hossein Mozdarani}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijrr.com/article-1-651-en.html}, eprint = {http://ijrr.com/article-1-651-en.pdf}, journal = {International Journal of Radiation Research}, issn = {2322-3243}, eissn = {2345-4229}, year = {2010} }