Dose In Air Research Articles

Improving the approach to calculating shielding in computed tomography rooms

The study assessed the acceptability of the currently existing approach to calculating shielding in computed tomography rooms and formulated proposals for its improvement, taking into account the parameters of research in domestic medical practice. It is proposed to use the dose-length product as the main measured parameter in the new approach to calculating shielding. Typical tomograph workload values of dose-length product, typical for examinations in the Russian Federation, were assessed. Using thermoluminescent detectors, the experimental assessment of the distribution of absorbed dose in the air in a computed tomography room was carried out. The experimental results showed that the distribution of of X-ray exposure in the central plane is not isotropic. Due to the attenuation of exposure by the gantry design, “shadow” zones are observed, where the absorbed dose reduction in the air reaches 10-13 times compared to its level in the direction of couch movement. Based on the results of measurements of the distribution of absorbed dose in air, the relative scatter coefficients were calculated. The workload was determined for 7 tomographs (1 in St. Petersburg and 6 in Moscow). For each tomograph, the average weekly number of head and body examinations and the values of dose-length product for these areas were assessed, taking into account the number of multiphase examinations. The obtained workload values turned out to be one or two orders of magnitude higher than those currently used in calculating shielding. Based on the results of the study and literature data, the work proposes a new approach to calculating shielding in computed tomography rooms, based on the value of measured dose-length product during the examination and allowing to take into account the specifics of the operation of the device.

Дозы на весь организм и их неопределенность при облучении мышей на гамма-радиобиологической установке ИГУР-1М

In the experimental department of the Urals research center for radiation medicine (Chelyabinsk, Russia) the radiobiological studies are carried out with the IGUR-1M gamma installation. In this study, the numerical experiment has been performed to specify the radiation doses in experimental mice and corresponding uncertainties. We evaluate the factors converting the dose in air measured by the ionization chamber to the dose to an organism, which is dependent on the height of the cage with the animals. The relative standard uncertainties of radiation doses for mice under 7 days of age do not exceed 7%. For more active older animals, the uncertainty of the delivered radiation doses can reach 10%.

High-performing structural optimization of graphene quantum dots as glyphosate herbicide photoluminescent probes: real case studies and mechanism insights

The widespread usage of the herbicide glyphosate calls for urgent action, aiming at the development of new, simple, low-cost, and eco-friendly detection approaches. In the last decade, investigation of graphene quantum dots (GQDs) as potential optical probes for various pollutants rapidly grew, thanks to their easy-manipulative structure, remarkable photoluminescence (PL) in the visible part of the spectrum, good dispersibility, biocompatibility, and non-toxicity, as well. Herein, a fast, simple, and environmentally friendly method for GQDs structural modification is presented. GQDs raw powder was exposed to γ- rays at three different doses (100, 200, and 300 kGy) in air, without any solvent or reagents. Irradiation of dots under such affordable conditions led to the additional incorporation of oxygen-containing moieties in the GQD structure. For the first time, oxygen-rich GQDs irradiated at a 300 kGy dose were successfully applied as direct turn-off PL probe for glyphosate detection. The high coefficient of determination (R-squared (R2) = 0.99) and very low limit of detection (3.02 μmol L-1) reveal good linearity between the potential sensor and analyte, as well as sensitivity. Glyphosate was successfully detected in celery samples, with a recovery value of 107 ± 0.85%. To evaluate the biological safety of the proposed sensing probe, [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) and the hemolysis assays were performed. Obtained results show that irradiated and non-irradiated GQDs did not cause the death of MRC-5 cells, and hemolysis of erythrocytes. The obtained results demonstrate that GQDs irradiated in an air medium can be potentially applied for glyphosate detection.

Assessment of NORMs (238U, 232Th, 40K) and radiation hazard indices in Beldih apatite mine region of Purulia district, West Bengal, India.

The radiation arising from naturally occurring radioactive materials (NORMs) is the foremost contributor to the collective dose received by the global population. The present study aims to measure the natural background radiation level and the associated gamma radiation dose in air in the Beldih apatite mine region of Purulia district, India. This study is primarily focused on the determination of 238U, 232Th and 40K activities in the sub-surface soil of the study area. The measurements were carried out using a High Purity Germanium (HPGe) detector-based gamma-ray spectrometer with a relative efficiency of 80%. To achieve uniformity in exposure estimations, radium equivalent activity has been calculated. Additionally, the internal hazard index, external hazard index, radioactivity level index and gamma dose rates have been evaluated to estimate the radiation hazard levels in the study area. The comparison of obtained concentrations and hazard indices with global data (UNSCEAR. (2008). Sources, effects and risks of ionizing radiation. United nations scientific committee on the effects of atomic radiation (report to the general assembly, with Annexes).) suggests that this region lies in a relatively high background radiation zone.

A NEW DOSE DETERMINATION METHOD FOR HP(3) AND DP LENS FOR BETA REFERENCE RADIATION QUALITIES.

For the purpose of obtaining the smaller uncertainties for Hp(3) and Dp lens in 90Sr/90Y beta reference fields, a new dose determination method based on the Monte-Carlo simulation was proposed. The conversion coefficients from the absorbed dose in air, at the reference point of the extrapolation ionisation chamber, Dair, det to Hp(3; α) and the conversion factors from Dair, det to Dp lens(α) were calculated with EGSnrc, respectively, for the irradiation angles from 0° to 60°. Compared with the dose determination method in International Organization for Standardization (ISO) 6980 standard, the uncertainty reductions of 7.7-52.8% for Hp(3; α) and 7.9-55.0% for Dp lens(α) were achieved, respectively. In addition, for the conversion coefficients from the reference absorbed dose DR to Hp(3; α), the calculations were performed for more irradiation conditions, which are not included in the current ISO 6980 standard. For the calculations of the conversion factors from DR to Dp lens(α), the eye and head phantoms with Chinese characteristics were utilised, which makes the conversion factors more suitable for use in China.

Auto-commissioning of a Monte Carlo electron beam model with application to photon MLC shaped electron fields

Objective. Presently electron beam treatments are delivered using dedicated applicators. An alternative is the usage of the already installed photon multileaf collimator (pMLC) enabling efficient electron treatments. Currently, the commissioning of beam models is a manual and time-consuming process. In this work an auto-commissioning procedure for the Monte Carlo (MC) beam model part representing the beam above the pMLC is developed for TrueBeam systems with electron energies from 6 to 22 MeV. Approach. The analytical part of the electron beam model includes a main source representing the primary beam and a jaw source representing the head scatter contribution each consisting of an electron and a photon component, while MC radiation transport is performed for the pMLC. The auto-commissioning of this analytical part relies on information pre-determined from MC simulations, in-air dose profiles and absolute dose measurements in water for different field sizes and source to surface distances (SSDs). For validation calculated and measured dose distributions in water were compared for different field sizes, SSDs and beam energies for eight TrueBeam systems. Furthermore, a sternum case in an anthropomorphic phantom was considered and calculated and measured dose distributions were compared at different SSDs. Main results. Instead of the manual commissioning taking up to several days of calculation time and several hours of user time, the auto-commissioning is carried out in a few minutes. Measured and calculated dose distributions agree generally within 3% of maximum dose or 2 mm. The gamma passing rates for the sternum case ranged from 96% to 99% (3% (global)/2 mm criteria, 10% threshold). Significance. The auto-commissioning procedure was successfully implemented and applied to eight TrueBeam systems. The newly developed user-friendly auto-commissioning procedure allows an efficient commissioning of an MC electron beam model and eases the usage of advanced electron radiotherapy utilizing the pMLC for beam shaping.

Assessment of environmental gamma dose in air in Ho Chi Minh city, Vietnam

Assessment of environmental gamma dose in air in Ho Chi Minh city, Vietnam

RADIOLOGICAL ASSESSMENT OF NATURAL RADIOACTIVITY IN A URANIUM DEPOSIT AREA: KÖPRÜBAŞI, TÜRKIYE.

In this study, the results of environmental radioactivity studies conducted in Köprübaşı, Manisa district, where Türkiye's uranium mineral exploration and processing studies were carried out, are shared. Because this is a populated area, there is a need for radio ecological dosimetry assessment to investigate the possible risk to the population. The region where radiological monitoring is carried out is discussed in two parts as the areas where uranium mineral exploration is performed and the settlements close to these areas. It was observed that 714-4714 nGy/h values were obtained in the outdoor absorbed dose rate in air measurements taken in the areas where mineral exploration was performed and this value reached up to 22857 nGy/h in open field mining areas. In the residential areas, it was recorded that the outdoor absorbed dose rate in air values ranged between 142 and 242 nGy/h and the indoor values ranged between 171 and 400 nGy/h. The world absorbed dose rate in air average values is 57 nGy/h (outdoor) and 75 nGy/h (indoor). The high 226Ra values in the radioactivity analyses of the soil samples draw attention. The mean values of the activity concentrations of the radionuclides 226Ra, 232Th and 40K in the soil samples are 3169, 55 and 802Bq/kg and the world averages of these values are 35, 30 and 400Bq/kg, respectively. It was determined that high 226Ra value in the soil in the areas close to the open field uranium mining area was passed on to the agricultural products. Radioactivity measurement results of drinking water samples did not exceed World Health Organization guidelines. According to the radon gas measurement results of 44 houses in Köprübaşı villages, the average radon concentrations in winter, spring, summer and autumn seasons were 72, 61, 50 and 55Bq/m3, and the annual average value was 60Bq/m3, respectively. Although these values are greater than the world average of 46Bq/m3, they are below the recommended limit value (100Bq/m3). By evaluating the data obtained, the total annual effective equivalent dose values (originating from outdoor-indoor absorbed dose in air, drinking water and indoor radon gas concentration) to which the people in the region are exposed were calculated as a 3.12mSv.

Hypoxic Conditioning in Rehabilitation and Secondary Prevention Programs in Cardiac Patients with Multimorbidity: a Review

INTORDUCTION. Patients with multiple chronic diseases are at higher risk of premature death, hospitalization, longer hospital stays, and reduced health-related quality of life compared to patients with a single disease. On the other hand, the presence of comorbid conditions limits the enrolment of traditional exercise-based cardiac rehabilitation programs. It is predicted that as life expectancy increases, the level of multimorbidity will increase, making it even more important to find new additional methods and technologies for the rehabilitation of cardiac patients with comorbidities. AIM. To analyze the data from the current publications or to define the validity and effectiveness of using different hypoxic conditioning regimens in cardiac patients with concomitant chronic pathology (arterial hypertension, obesity, diabetes mellitus, and chronic bronchopulmonary diseases) as well as in multimorbid elderly patients. MATERIAL AND METHODS. The search for relevant papers was carried out using the Medline, e-library, and Web of Science Core Collection databases, as well as the following keywords: “hypoxic conditioning”, “hypoxic training”, “hypoxic therapy”, “interval hypoxic therapy”, “intermittent hypoxia”, “hypoxic conditioning”, “interval hypoxia training”, and “hypoxic exposure”. The analysis included publications regarding the use of the hypoxic conditioning method in cardiac and elderly patients with multimorbid pathology, as well as publications on the use of the method in the rehabilitation of patients with certain nosologies to identify potential mechanisms in correcting bronchopulmonary violations and lipid and carbohydrate metabolism disorders. The last search date was April 05, 2022. RESULTS. Most of the analyzed studies proved that the hypoxic conditioning technology in passive interval exposure regimes is an effective method for non-pharmacological correction of cardiometabolic risks in cardiac patients with multimorbid pathology and can increase exercise tolerance, optimize hemodynamic parameters (HR, SBP and DBP), reduce the manifestations of bronchial obstruction and respiratory failure, and improve cognitive function and metabolic indicators. Personalized physical activity doses in oxygen-depleted ambient air appear to be promising, but require additional studies to establish optimal application protocols. CONCLUSION. The data presented may recommend hypoxic conditioning technologies for wider implementation in cardiac rehabilitation programs for patients with multimorbid pathologies.

Estimation of radiological impact of the activities of Olusosun Dump Site on workers and dwellers of Olusosun, in Lagos Southwest Nigeria.

This study assessed the potential radiological risks associated with the activities on Olusosun dump site on workers and dwellers of Olusosun community. The activity concentrations of 238U, 232Th and 40K from of soil and water samples were determined using High-Purity Germanium (HPGe) detector. The background radiation level of Olusosun dump site was measured using a portable Geiger-Müller counter-Radeye B20 survey meter. The mean value of background radiation was 1.46mSv/yr. This value is about 46% higher than the recommended reference level of 1.0mSv/yr for the public. The mean activity concentrations of 238U, 232Th and 40K in the soil samples were 19.1 ± 3.2, 29.1 ± 4.4 and 171.5 ± 6.1Bq/kg respectively which are about 45.4%, 35.3% and 59.2% lower than the world's average levels. For the water samples, the mean activity concentrations obtained for 238U, 232Th and 40K are 0.4 ± 0.4, 0.8 ± 0.2 and 0.8 ± 0.3Bq/l respectively. These are about 99.9% and 20% lower than WHO reference levels for 238U and 232Th. The mean absorbed dose rate in air (D), Annual effective dose (AED) outdoor, Radium Equivalent (Req), External hazard index (Hex) internal hazard index (Hin) and Excess lifetime cancer risk (ELCR) from soil samples were 33.6 nGy/h, 41.0μSv/yr, 73.1Bq/kg and 0.2, 0.3 and $1.4\times{10}^{-4}$, respectively. Absorbed dose in air D, AED outdoor, Req, Hex, Hin and ELCR are 41.1%, 41.4%, 80.3%, 80%, 75% and 50% lower than their corresponding world's average and references. The estimated AEDw from ingestion of water is 148.9 ± 50.4μSv/yr, this is about 49% higher than the WHO reference level of 100.0μSv/y from ingestion of water. The radiological hazard indices estimated from soil samples do not indicate any potential risks to the users. The elevated background radiation level of the dump site, and AEDw from ingestion of water, however, suggest that the activities on Olusosun dump site pose potential radiological risks on workers on the site and the public from consumption of water from Olusosun community.

PHSOR03 Presentation Time: 12:40 PM: Radiation Dosimetry of a Dual-Modality Balloon Implant for Simultaneous HDR Brachytherapy and Magnetic Nanoparticle Hyperthermia to Treat Brain Tumor Resection Cavities

<h3>Purpose</h3> Glioblastoma multiforme (GBM) is an aggressive brain tumor that generally recurs locally and has a dismal median survival of less than 18 months<i>. In vivo</i> studies have shown that simultaneous hyperthermia and radiation can enhance the radiation response by a factor of up to 5. Our group developed a novel dual-modality thermobrachytherapy (TBT) balloon device to accomplish this goal. The balloon will combine magnetic fluid hyperthermia and HDR brachytherapy, which will be delivered right after brain tumor resection, so that the at-risk tissue adjacent to the tumor resection cavity will conform to the balloon shape and receive uniform radiation and thermal dose. This abstract focuses on the possible effects of hyperthermia on radiation dosimetry as well as the effects of balloon shape. <h3>Methods</h3> The current version of our TBT balloon device consists of a balloon filled with magnetic nanoparticle solution (nanofluid) and a flexible sheath with three ports to insert the HDR catheter and fiber-optic thermal probe and inject the nanofluid. We tested the balloon in air and activated the nanofluid using an external magnetic field induced by a 133 kHz induction coil. Two balloon designs were tested: a spherical one with 4 cm diameter, and a teardrop-shaped balloon with an axial diameter of 3 cm and measuring 3.7 cm along the shaft. We used Gafchromic film and RIT imaging software to analyze the in-air dose distribution of an HDR source dwell in both types of balloons, filled with distilled water and then nanofluid, as well as without and with simultaneous hyperthermia, where the coil power was escalated until reaching intra-balloon temperatures greater than 55°C. Experimental setup and radiation dose profiles can be found in Figure 1. <h3>Results</h3> The presence of the nanofluid, magnetic field and heat up to 66°C did not affect radiation dose distribution significantly in the spherical balloon (less than 10% difference). However, the teardrop-shaped balloon dose profiles showed a notable difference (about 20%) in dose magnitude with the presence of nanofluid and/or heat. Nonetheless dose distributions looked symmetrical in all cases. <h3>Conclusions</h3> The current device design is still in progress, but this study illustrated that a spherical balloon shape may be preferential for simultaneous hyperthermia and HDR brachytherapy. Furthermore, this radiation dosimetry study demonstrated compatibility and robustness of the prototype balloon components and desirable symmetrical dose distribution.

Characterization of Radio-Photo-Luminescence (RPL) Dosimeters as Radiation Monitors in the CERN Accelerator Complex

Dosimetry is a crucial activity in irradiation campaigns to qualify electronics and materials to operate in radiation environments. In addition, it also provides means of monitoring radiation levels in accelerator environments to prevent radiation damage to the machines and improve system lifetime. Therefore, this work provides the characterization of radio-photo-luminescence (RPL) glass dosimeters as a high-level radiation monitor to be used in the mixed radiation fields observed in CERN’s accelerator environment as well as in irradiation campaigns for the qualification of electronic components and materials. Here, two methods to improve the measured dose are presented, one for the correction due to the fading of the RPL dosimeters (RPLDs), where an improvement of over 40% of the measured to the expected dose could be achieved, and one method that corrects the measured dose in mixed-particle fields to dose in water or air.

Influence of the irradiation geometry on the severity of acute radiation damage

The aim of this study was to demonstrate how the severity of radiation damage in the case of bone marrow syndrome due to acute irradiation depends on the non-uniform irradiation of the body. We used the calculation method that involves the evaluation of organism mortality as a function of bone marrow cells colony survival vs dose for different radiation profiles. It was presumed that the probability of the death for the organism is the same for the same value of survival level of the bone marrow cells regardless of the dose distribution by mass of the organ. The dose of uniform irradiation that is equivalent to the dose for the L-th case of non-uniform irradiation is calculate based on the survival level of the total marrow cells. After that the probability of the death of the organism is estimated according to the dose response curve. Dose distribution in bone marrow of computational MIRD-5-type stylized model adult man for different geometries of exposure by point source of 137Cs was evaluated. Larger non-uniformity of the dose distribution in the bone marrow at the same dose in free air in the site of human location causes a greater probability of survival due to a greater proportion of bone marrow cells that have preserved the possibility of reproduction. The values of mean 50% lethal dose for cases of approximately uniform irradiation of the body surface (point source at a distance 10m) and sharply non-uniform irradiation (point source at a distance of 0.5 m) differ approximately by the factor of 1.7 – 2.5 depending on direction of irradiation. Additionally the values of conversion coefficients from the reading of an individual dosimeter to the value of an effective dose for various geometries of irradiation of emergency workers from the 137Cs point source were calculated. The average value of the conversion coefficient from personal dose to effective dose for the considered exposure situations is 0.7 Sv Cy-1 and the 90% confidence interval is 0.49 – 0.99 Sv Gy-1.

Development of the Radiation Protective Curtain for the Dose Reduction of Caregivers during Computed Tomography Examinations

During computed tomography (CT) examinations, it may be necessary to assist the patient to maintain an appropriate body position. However, there is little protective equipment available for caregivers who approach the gantry. This study aimed to evaluate the effectiveness of novel radiation protective curtains in reducing radiation exposure to caregivers while assisting patients, especially during CT examinations of the head. The absorbed dose in air around the gantry during CT examinations of the head was measured using glass dosimeters. The measurement points from the center of the gantry were 40 to 120 cm in the front, 0 to 100 cm for each side in the right and left, and 60 to 180 cm from the floor. Measurements were performed at each 20-cm interval, and all points were accumulated 10 times. The absorbed dose in air in a CT room was compared with and without the protective curtains. Next, we assumed the height of the caregiver to be 170 cm, and measured the points for the crystalline lens, chest, and abdomen. Also, using the protective glasses and the protective apron, we measured the absorbed dose in air for the caregivers behind the protective curtains. The absorbed exposure dose in air toward the crystalline lenses, chest, and abdomen was reduced more than 90% by using the protective curtains and more than 95% by using the protective apron and protective glasses in addition to them. This study showed the usefulness of protective curtains in reducing the absorbed exposure dose in air to caregivers.

Natural Radioactivity Evaluation and Radiological Peril in some soil specimens of Al-Taimeem Area in Al-Anbar Province, Iraq

In the present work, the radioactivity of ten soil specimens has been measured, which were gathered from various sites from AL-Taimeem area in Al-Anbar province, The qualitative activity of natural radionuclides 238U, 232Th and 40K for soil specimens were evaluated by utilizing gamma-ray spectroscopy with NaI(Tl) detector of (3"×3") dimension. The results revealed that, the qualitative activity, for 238U was varied from (14.730 Bq/kg) to (28.070 Bq/kg), for 232Th was varied from (16.510 Bq/kg) to (29.480 Bq/kg), for 40K was varied from (143.820 Bq/kg) to (231.550 Bq/kg) ,with an average values of (21.152±2.98 Bq/kg) , (24.219±3.93 Bq/kg), (190.720±22.20 Bq/kg), successively. To survey the radiological peril in soil, radium effective activity, absorbed gamma dose in air, annual effective dose equivalent (inner and outer), gamma concentration level index and both (interior and exterior) radiation peril index have been computed, and all the existed results were less than recommended by the International Committee for the Radiation Protection (ICRP).

New concept of in/out air quality control in livestock buildings

The object of this research is the new concept of the original universal system for air quality and energy control in laboratory conditions (wet scrubbing system) based on the ?clean air in/out? principle. Namely, the process involves a partial or complete exchange of recirculated treated air. From the aspect of water, as a pure medium, the system is characterized by broad application in the open, semi-open, and closed air treatment systems: primarily in the breeding and accompanying agricultural facilities, industrial, cultural, sports, tourist, medical and other controlled spaces. The analysis showed that the system at its inlet unit and with the block structure and logical phase development, proved energy, environ-mental and qualitative efficiency in the removal of PM10 and PM2.5 particles from the controlled dust doses in laboratory air. The measurements of PM10 and PM2.5 concentrations were performed with two Alphasense OPC-N3 optical counters at the inlet and outlet of the system. Five operating regimes with frequency regulated number of revolutions of the turbo elements that was taken as an independent variable, achieved different degrees of removal of PM10 and PM2.5 from the treated laboratory air: 97.70-98.53% and 62.19-75.75%, respectively. The assessment of system energy use was done by parallel measuring of electric power and comparative deviations of its absolute values in the first decimal. Energy consumption for the treatment of 1m3 of air ranged from 0.00011- 0.00016 kWm?3. Statistical analysis of qualitative indicators revealed significant differences between the operating regimes and the obtained values.

Study and Characterization of Natural Radioactivity Levels and Radiological Hazards of Soil in Wasit Governorate

In this paper studied and measured the natural radioactive for agricultural soil samples surrounding Kut as well as gardens, home, casinos and others. Eighteen samples of agricultural land were taken on three deep depths the first depth 10 cm and the second 20 cm and the third 30 cm. Twenty-five samples were taken from public parks, parks, casinos and other parks. They are all measured using a system NaI (Tl) 3″ × 3″. The results that the radioactive effectiveness of uranium for all samples are ranged 17.19 to 38.68 Bq/Kg and at a rate of 30.55 Bq/Kg for all samples. Thorium series values were between 56.45 to 13.26 Bq/Kg with average 38.60 Bq/Kg. With regard to potassium, values were ranged 537.20 to 118.30 Bq/Kg at a rate of 250.25 Bq/Kg. The values of radioactive effectiveness for potassium are within the globally allowed compared with the radioactive effectiveness of the Thorium. The radium equivalent and the rate absorbed dose in air and the external and internal hazard index and the annual effective dose has been calculated and that all values are within the globally allowed limits.

Contribution of soil in the annual effective dose due to radon in the air of some dwellings in the city of Karbala, Iraq

Abstract Introduction: The radon isotopes are not as significant as (222Rn) due to the decay of the natural radionuclides (235U), (232Th) and (238U) due to their short half-life, at most. (222Rn) can be classified as among the most harmful radioactive elements in the world. Material and method: In this analysis, the closed-can technique was used with solid-state nuclear track detectors (CR-39). After forty days of closed dosimeter buried in the soil of the garden, and ninety days from the closed position in the air of some dwellings were collected dosimeter and stripped of nuclear detectors impact of closed groups. For 8 hours, CR-39 detectors were chemically etched by (6.25 N) NaOH solution at 70°C and then registered within an optical microscope. Result: The levels of soil radon concentrations ranged from 28.44±0.58 to 479.76±2.43 Bq/m3 with a mean value of 220.33±1.64 Bq/m3, while the concentration of radon in the air of certain dwellings varied from (1.95±0.27 to 46.82±0.75) Bq/m3 with an average value of 21.51±0.54 Bq/m3. In comparison, the annual effective dose attributed to radon in soil ranged from 0.71±0.09 mSv/y to 12.10±0.38 mSv/y with an average value of 5.55±0.261 mSv/y, while the annual effective dose in air differed from (0.04±0.02 mSv/y) to (1.18±0.12 mSv/y) with an average value of (0.60±0.09 mSv/y). Conclusion: Neglecting the effects of other radon sources, the percentage share of the annual effective dose due to radon in soil measured in the air home, ranged from 0.005±0.001 to 0.453±0.074 with an average value of 0.130±0.040. Weak correlation between concentrations of radon in households and soil air. But roughly speaking, one can say that in soil air every 1000 Bq/m3 and 1000 mSv/y contributes around 130 Bq/m3 and 130 mSv/y in indoor air.

Exposed Gamma Doses in air and Assessment of Cancer Risk around Gebze (Kocaeli/Turkey) Region

By this study, it is focused to assessment of inhalation quality for Kocaeli province especially Northeast side of Marmara Sea (Gebze county and its territory). In this case, radioactivity analysis in air was realized via air dose rate measurements around this region which is so closed neighbor to big city Istanbul. By measuring of the outdoor gamma dose rates on 35 stations, it was possible to get the average dose rate. Then it was calculated to annual dose in air. Besides, cancer risk was determined for Kocaeli. All these values were compared with the World’s references (UNSCEAR) and reported finally. It was measured the average dose rate as 23.90 nGyhr-1 and annual dose was calculated to 29.31 μSv. This dose is required to excess lifetime cancer risk as 1.02x10−4. These values could be compared to the similar studies which existed around the world. Finally, the average annual effective dose equivalent and excess lifetime cancer risk for Kocaeli, are less than the world average. This study would be used to a reference for further investigations, besides it will be usefull to compare with different studies for Kocaeli which, will be evaluated in the future, for example after a nuclear pollution, such as based on a reactor leakage comes from Black Sea region and neighbours, nuclear attacks, etc., too. Another benefit would be made to enlarge to find this kind of studies in literature.

Gamma-Ray Modified Polymer/Clay Composites: Synthesis, Characterization, and Formulation Optimization Using Multivariate Calculus and Graph Theory

To enhance the oxidation strength and crosslinking yield of ultrahigh molecular weight polyethylene (UHMWPE), its composites were prepared by mixing 1%, 2%, and 3% (by wt.) of magnesium silicate hydrous (sepiolite) during this study. These composites were irradiated with 25 kGy and 50 kGy of irradiation doses in the open air. Subsequent to irradiation, the composites were characterized for updates in structure, oxidation strength, and degree of crosslinking while estimating the values of oxidation index (OI), crosslink density (Gx), and percent crystallinity (Xc), respectively. The reaction of modified sepiolite (SP) on irradiating UHMWPE/SP composites was evident from the origination of peaks at Si-O, O-Si-O, Si-O-Si, and Mg-OH and stretching vibration at 974 cm−1, 1014 cm−1, and 1080 cm−1, respectively. In addition, the moderate negative correlation of OI (−0.46) and strong positive correlation of Gx (0.87) with the absorbed dose, made obvious from correlation analysis, confirmed the effectiveness of SP in enhancing the oxidation strength and crosslink density of UHMWPE. Furthermore, cluster analysis (CA) grouped the composites as low, moderate, and best based on dissimilarities, i.e., oxidation strength and crosslink density, which was further confirmed by principal component analysis (PCA). PCA also revealed that the OI, Gx, and absorbed dose were the active variables for this best group. After confirming the effectiveness of SP (as an active filler for enhancing the oxidation strength and crosslink density of UHMWPE) and recognizing the OI, Gx, and absorbed dose as active variables, the next step was to determine the necessary minimum amount of SP concentration and radiation dose required for the composite that outperforms all others. For this, a parametric graph theory and matrix approach was employed to rank the composites of the best group, revealing that the UHMWPE/SP composite with 1% (by wt.) of Si12O30Mg8(OH)4(H2O)4·8H2O and irradiated with 50 kGy of irradiation dose was the most suitable choice of all existing alternatives tested in this study. Although this is the first attempt, to the best of our knowledge, where a smart approach using multivariate calculus and decision-making tools was utilized for figuring the best UHMWPE composite formulation along with appropriate treatment dose, the results and methodology could be extended for any polymer of industrial scale, such as those used in medical implants, defense armor, bulletproof jackets, etc.