p .mehnati

Natural and artificial radioactive materials are the most important sources of radiation for human existing in all over the world, thus investigating their radioactivity is of great importance because of their ionizing properties and harmful effects on human health. Therefore, this study was conducted to measure radionuclides concentrations of 226Ra, 232Th, 40K and 137Cs in sediment samples collected from various hot springs in Kerman province and also determining received annual effective dose.

Thirteen sediment samples were collected from different hot springs and concentrations of radionuclides in sediment samples were measured via spectrometry method and using HPGe detector. To evaluate radiation hazards caused by these radionuclides, radium equivalent activity, absorbed dose rate in air, and annual effective dose of samples were calculated.

Concentrations of 226Ra, 232Th, 40K and 137Cs in sediment samples varied from 21.01±0.71 to 193.16±1.72, 16.84±1.21 to 245.92±2.69, 90.13±3.37 to 667.81±14.59 and <MDA to 5.81±0.66 Bqkg-1, respectively. Also, minimum and maximum values of annual effective dose were determined as 0.17±0.00 and 1.48±0.01 in mSvy-1, respectively.

Comparison of radionuclides concentrations and annual effective dose obtained in this study with the worlds̓ average values determined by UNSCEAR (2000) reports showed that concentrations of 226Ra and 232Th in 69% and concentration of 40K in 46% of measured samples were higher than the worlds̓ average values. Also, annual effective dose of 30% of samples was found to be higher than the worlds̓ average value.

Human exposure to Radon-222 gas is one of the most important natural radiation sources of radioactive gases, and inhalation of this gas and its decay products can cause lung cancer. Therefore, this study was conducted to measure Rn-222 concentration and determine annual effective dose of radon inhalation in the vicinity of hot springs in Kerman province, southeastern Iran.

This study was carried out on 16 hot springs of Kerman province. Concentration of Rn-222 was measured using RAD-7 electronic system. Also, annual effective dose amounts of inhalation were estimated according to the formula provided by UNSCEAR (2000).

Minimum and maximum amounts of Rn-222 concentration in the samples were equal to 0.158±0.129 and 56.100±5.680 Bql-1, respectively. Annual effective dose amounts of inhalation were determined between 0.000±0.000 to 0.177±0.017 mSvy-1. Concentration of radon was more than 11 Bql-1 (the safe limit set by the EPA) in 5 samples collected from hot springs. Annual effective dose of inhalation of radon was more than 0.1 mSvy-1 (the safe limit set by the WHO) in Jooshan hot spring.

By comparing concentration amounts of the samples with the EPA safe limit, it was concluded that, 11 hot springs were safe. Also, annual effective dose amounts of inhalation of all hot springs, except one of them were lower than the safe limit set by WHO.

Bismuth Polyurethane composite is a novel shield for breast protection while saving image quality in chest CT. Bismuth different concentrations used for constructing polymer composites breast shields in this study.

Bismuth with particle size <150 micrometer used in bismuth polyurethane composite (BPC) with a ratio of 10%, 15% and 1.1, 2.2 mm thicknesses. The BPC was examined on the female chest phantom (skin and fourth layers), 120 kV and 80 mA selected as an exposure factors in chest CT. The dose reduction was recorded by TLD and the image quality was evaluated quantitatively and quantitatively.

Using BPC shields 10% and 15% (2.2 mm) induced to breast dose reduction to 69.1% and 77.5% for skin layer and 44.7% and 52.8% for fourth layer, respectively.  The image noise Increasing in BPC for breast and mediastinum areas were 9.43% (P=0.347) and 15.44% (P=0.386), respectively.

Application of Bismuth with different weight ratios in polyurethane composite was useful shield for radiation dose reduction of the breast in chest CT.

The solar radiation consists of a vast spectrum of wavelengths such as visible light and ultraviolet radiation (UVR). The amount of UVR that reaches the Earthchr('39')s surface is very important due to its role in vitamin D synthesis and causing skin cancers. The hourly and daily mean values of solar UV type A, B, and visible light radiation were measured for the first time during the year.

The hourly and daily mean values of UVR and visible light intensity of solar radiation at Tabriz were measured and analyzed between the 2017 and 2018 years. The intensity of solar UVA and UVB radiation was measured by Hand-held Lux-UV meter device from sunrise to sunset for one hour.

The results showed that the highest values of UVA and UVB radiation, reaching the Earth were between 12 and 13 o’clock. The maximum and minimum values of UVR were recorded during the months of May and January, respectively. The maximum amounts of UVA and UVB during the whole year were 52.48 and 2.82 W/m2, respectively. Also, the lowest intensity of UVA and UVB radiation during the whole year was 22.19 and 0.79 W/m2, respectively.

Comparison of maximum and minimum UV amounts of type A and B in May was about 2.36 and 3.56 times more than in January. The measurements showed that the intensity of UVA was significantly higher than UVB amounts.

Application of CT- scanning image information and radiation physical characteristics of the biomaterials are two measurable assays for presenting modified cells.

This study presented that CT number (HU) and linear attenuation coefficient contain useful information which can be determined during usual CT scanning for the prediction of breast cancerous cells existence based on hemoglobin concentration.

This experimental study used breast phantom containing major and minor vessels with diameters of 10 and 5 mm, respectively. The major vessels are filled by water, fat, hemoglobin (Hb) as a normal and 4× concentration of hemoglobin (4×Hb) as a cancerous breast cells, then scanned by single slice CT (GE, Hi Speed) 120 kVp, 100 mA for the determination of linear attenuation coefficient (µL).

The CT numbers were for water (-7 to +7 HU), Hb (22±6 HU) and 4×Hb (80±4 HU). The difference between Hb and 4×Hb was significant (p <0.000). Minimum µL was 0.1190±0.00680 cm-1 for fat and maximum was 0.1449±0.00794 cm-1 for 4×Hb.

The study of CT number and linear attenuation coefficient of different concentration of Hb provides a possibility for early predicting of breast cancerous cells existence (4×Hb).

During interventional cardiology processes, patients especially women and children receive high radiation doses due to their sensitivity. In this study, we evaluated a pediatric patient dose separately in those undergone intervention cardiac procedure. In this cross sectional study, a public hospital with 252 patients, Entrance Skin Dose (ESD) and Dose-Area Product (DAP) were recorded. Prior to the beginning of fluoroscopic procedure, the chest thickness and Body Mass Index (BMI) of patients were measured. Furthermore, kV, mAs, angle of tube and time of angiography and angioplasty were recorded. Children ratio to all patients underwent the cardiovascular imaging was 1.8. The means of patients’ ESD, DAP and fluoroscopy time were 178.3±17 mGy, 1123.6±11 μGycm2 and 281.4±181.2 s, respectively for coronary angiography. The females were 96.8 under 30 years and their dose mean was 276±37 mGy, 368±24 μGycm2 for ESD and DAP received, respectively with 376s fluoroscopy time. Mean mAs was 359±34 and kV was 71.23±2.7. Above all, a direct and significant correlation was found between the patients’ chest thickness with kV (p=0.037, r = 0.11) and mAs (p<0.001, r = 0.28) variations. The results demonstrated that the number of children referred to the cardiology department and also the dose rate received by them during this test was higher than the data provided for children in developing countries. Paying attention to the children’s perception of high-fluorescence time is necessary in comparison with total angiography time in order to reduce the number of radiation injuries among pediatrics.