Samples of natural and manufactured building materials collected from Algiers have been analysed for 226Ra, 232Th and 40K using a high-resolution HPGe gamma-spectrometry system. The specific concentrations for 226Ra, 232Th and 40K, from the selected building materials, ranged from (12-65 Bq kg(-1)), (7-51 B qkg(-1)) and (36-675 Bq kg(-1)), respectively. The measured activity concentrations for these natural radionuclides were compared with the reported data of other countries and with the world average activity of soil. Radium-equivalent activities were calculated for the measured samples to assess the radiation hazards arising from using those materials in the construction of dwellings. All building materials showed Ra(eq) activities lower than the limit set in the OECD report (370 Bq kg(-1)), equivalent to external gamma-dose of 1.5 mSv yr(-1).
The present study concerns measurement of the radon concentration in drinking and irrigation waters obtained from the eastern part of Oman, in particular in regard to water quality assessment of the region. The samples were collected from different places covering most types of water sources in the region. A passive and time-integrated track etch detector (LR-115 type II) combined with a high-resolution optical microscope has been used to obtain the radon concentration in the studied samples. Values of dissolved radon in water varied among the water sources; the highest concentration of radon was found to be 363 Bq m-3 in a drinking water sample while well water used for irrigation showed the lowest value, at 140 Bq m-3. Measured data for all water sources are below the permissible limit of 11.1 kBq m-3 recommended by the US-EPA. Annual effective doses for the studied samples were in the range 0.38-0.99 μSv y-1 which is significantly less than the action level recommended by the WHO (0.1 mSv y-1), indicating that the water sources in the Jalan BBH region of Oman are safe to use. The obtained data may serve as a reference for any future radiological study of the waterbody of this region.
Age-related Macular Degeneration (AMD) affects the central vision of aged people. It can be diagnosed due to the presence of drusen, Geographic Atrophy (GA) and Choroidal Neovascularization (CNV) in the fundus images. It is labor intensive and time-consuming for the ophthalmologists to screen these images. An automated digital fundus photography based screening system can overcome these drawbacks. Such a safe, non-contact and cost-effective platform can be used as a screening system for dry AMD. In this paper, we are proposing a novel algorithm using Radon Transform (RT), Discrete Wavelet Transform (DWT) coupled with Locality Sensitive Discriminant Analysis (LSDA) for automated diagnosis of AMD. First the image is subjected to RT followed by DWT. The extracted features are subjected to dimension reduction using LSDA and ranked using t-test. The performance of various supervised classifiers namely Decision Tree (DT), Support Vector Machine (SVM), Probabilistic Neural Network (PNN) and k-Nearest Neighbor (k-NN) are compared to automatically discriminate to normal and AMD classes using ranked LSDA components. The proposed approach is evaluated using private and public datasets such as ARIA and STARE. The highest classification accuracy of 99.49%, 96.89% and 100% are reported for private, ARIA and STARE datasets. Also, AMD index is devised using two LSDA components to distinguish two classes accurately. Hence, this proposed system can be extended for mass AMD screening.
Radon exists naturally in the air. It can accumulate inside the buildings which may affect the indoor air quality. Radon is a radioactive gas that produces alpha particles during decay time. The alpha particles might cause harm to the human lungs and stomach. Inhalation of radon is one of the causes of lung cancer disease. Samples of inhaled radon in different rooms at the workplace were taken hourly through a passive diffusion chamber. The detection method was done using Alpha Spectrometry. The short term measurement was applied in the study to monitor the average weekly radon reading in different rooms in the Medical Imaging Laboratory of the University of Selangor (UNISEL). All tested rooms showed the existence of radon gas with different concentrations. Some of them showed the maximum reading of radon concentration which was higher than the radon action level of 148Bq/m3 or 4pCi/l. Their weekly average of radon concentration is contributing almost 50% of the accumulated radon concentration in the laboratory. It is highly recommended that monitoring the concentration of radon in indoor air is performed to ensure it is at a safe and healthy level.
The aim of this study is to design radon irradiation technique in the field of hematology for an invitro study. In addition, deposit of alpha particles into the human blood surface and its effects on the thrombocytopenia estimated using nuclear track detectors (NTDs). In this technique, amount of radon gas (2210±5.1Bq/m 3 ) collected in a tight PVC container with the appropriate engineering dimension using two sources of radium (5μCi). Blood samples (10 male and 10 female) and CR-39NTDs (40 pieces) are exposed to radon gas at various exposure time. Complete blood test and the computer scanning for each piece of CR-39NTDs before and after exposure has done. The results show that the present technique has a good efficiency (96%) to the invitro exposure of human blood. When the radon gas moved on the surface of blood sample, alpha tracks registered into CR-39NTDs. Thus, this technique improved that the comparative method to evaluate alpha particle density into exposure blood samples is an effective way; this depended on the geometry of design and the sensitivity of CR-39NTDs to track registration. Radon detector version 7 (RAD7) used to make a certain suitability of CR- 39NTDs. Amount of radon concentration losses during the exposure process, in the present work it was variable from 0.41% to 1.4%. Radon concentration effected on the thrombocytopenia; this depended on time of exposure and alpha energy loss into the blood and CR-39 through the atomic displacements. At the time of exposure of 10 minutes, rate of absorption dose was 2.255±0.11μSv (39%), and the platelet (PLT) cont reduced rapidly (high effected on reduce PLT, this makes thrombocytopenia.
Many studies were carried out throughout the world on radon measurement in water especially drinking water for it can cause problem to human health. This study is an attempt to measure the level of radon present in water collect from rivers and lakes. Data gathered from this study provides important information about radiation levels in water at selected sites, because radon gas is the largest contributor to natural radioactive radiation exposure to humans. Exposure to radon gas can cause lung cancer. Liquid scintillation counting (LSC) has been applied to determine the activity concentration of radon ( 222 Rn) in water. Water samples were collected from, ex-mining lake in Perak, Sok River in Kelantan, Tembeling River in Pahang. Water samples were prepared in polyethylene bottles mixed with liquid scintillator and stored for 3 weeks to allow 222 Rn and its progeny to reach the equilibrium, and the activity concentrations ranged from 0.24-1.27 Bq/L, and 0.029 – 0.155 Bq/L for radon and radium respectively.
Ground water contain natural radioactivity associated with uranium and thorium that present naturally in rocks and soils. Humans may be exposed to the emission of energetic alpha particle from supported radon decaying process in this water when it is inhaled or ingested. Assessment of supported radon in ground water was carried out using fourteen ground water samples from Cameron Highlands. The measurement was accomplished by degassing the water samples using pump and then allowing the gas to flow into specially constructed 0.0191 m8 metal chamber. The activity concentration of supported radon in water sample was measured using continuous radon monitor inside the radon chamber. Measurement was carried out at one hour interval for twenty four hours. The hourly supported radon concentration was found to stabilize after about 8 hours. The stabilized concentration was used to determine supported radon activity concentration in the water samples. Results of the study show that depending on the sampling location, the activity concentrations of supported radon are in the range from 0.09 - 0.48 Bq/L which is lower than the activity concentration of radon in drinking water as proposed by USEPA (11 Bq/L).
Radon gas has been known as one of the main factors that cause breathing complications which lead to lung cancer, second only after smoking habit. As one of the most commonly found Naturally Occurring Radioactive Materials (NORM), its contribution to background radiation is immense, and its contributors, Uranium and Thorium are widely available on Earth and have been in existence for such a long time with long half-lives. Indoor radon exposure contributed by building materials worsens the effects. The probability of inhaling radon-polluted air and being surrounded by it in any buildings is very high. This research is focused on the detection of radon emanation rate from various building materials which are commonly being used in Malaysia. Throughout this research, common building materials used in constructions in Malaysia were collected and indoor radon exposure from each material was measured individually using Tight Chamber Method coupled to a Continuous Radon Monitor, CRM 1029. It has been shown that sand brick is the biggest contributor to indoor radon compared to other samples such as sand, soil, black cement, white cement, and clay brick. From the results, materials which have high radon emanation could be reconsidered as building materials and mitigation action can be chosen, suitable to its application.