Displaying publications 41 - 60 of 238 in total

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  1. Environmental radioactivity levels in marine species from Malaysia and Fiji
    Dougherty G
    Health Phys, 1989 Jul;57(1):187-90.
    PMID: 2745081
    Matched MeSH terms: Cesium Radioisotopes/analysis*; Potassium Radioisotopes/analysis*
  2. Fulltext Estimation of (99)Mo production rates from natural molybdenum in research reactors
    Blaauw M, Ridikas D, Baytelesov S, Salas PS, Chakrova Y, Eun-Ha C, et al.
    J Radioanal Nucl Chem, 2017;311(1):409-418.
    PMID: 28111485 DOI: 10.1007/s10967-016-5036-6
    Molybdenum-99 is one of the most important radionuclides for medical diagnostics. In 2015, the International Atomic Energy Agency organized a round-robin exercise where the participants measured and calculated specific saturation activities achievable for the (98)Mo(n,γ)(99)Mo reaction. This reaction is of interest as a means to locally, and on a small scale, produce (99)Mo from natural molybdenum. The current paper summarises a set of experimental results and reviews the methodology for calculating the corresponding saturation activities. Activation by epithermal neutrons and also epithermal neutron self-shielding are found to be of high importance in this case.
    Matched MeSH terms: Radioisotopes
  3. Fulltext Power and neutron flux calculation for the puspati triga reactor using MCNP
    Mohamad Hairie Rabir, Julia Abdul Karim, Mohd Amin Sharifuldin Salleh
    Jurnal Sains Nuklear Malaysia, 2012;24(1):22-32.
    MyJurnal
    The Malaysian 1 MW TRIGA MARK II research reactor at Malaysian Nuclear Agency is designed to effectively implement the various fields of basic nuclear research, manpower training, and production of radioisotopes for their use in agriculture, industry, and medicine. This study deals with the calculation of neutron flux and power distribution in PUSPATI TRIGA REACTOR (RTP) 14th core configuration. The 3-D continuous energy Monte Carlo code MCNP was used to develop a versatile and accurate full model of the TRIGA core and fuels. The model represents in detailed all components of the core with literally no physical approximation. Continuous energy cross-section data from the more recent nuclear data as well as S (α, β) thermal neutron scattering functions distributed with the MCNP code were used. Results of calculations are analyzed and discussed.
    Matched MeSH terms: Radioisotopes
  4. Fulltext 210Po and 210Pb in cockle tissues in west coast of Peninsula Malaysia
    Che Abd Rahim Mohamed, Tee, Lee Theng, Zaharuddin Ahmad
    Journal of Nuclear and Related Technologies, 2006;2006(1):69-75.
    MyJurnal
    Natural radionuclides such as 210 Po and 210 Pb were analyzed in soft part of cockle (Anadara granosa) obtained from Kuala Selangor in the west coast Peninsular of Malaysia. The activity levels of both nuclides fluctuated within the size of cockles from 41.3 ± 2.5 Bq/kg to 114 ± 7 Bq/kg and 12.9 ± 1.7 Bq/kg to 96.8 ± 5.3 Bq/kg in dry weight (dwt) for 210 Po and 210 Pb, respectively. The level activity in wet weight (wwt) also varied from 8.60 ± 0.52 Bq/kg to 25.70 ± 1.63 Bq/kg and 2.47 ± 0.40 Bq/kg to 19.27 ± 1.05 Bq/kg for 210 Po and 210 Pb, respectively, probably related to the different of metabolic rate and growth of cockles. Activity ratio of 210 Po/ 210 Pb in dry weight also fluctuated from 0.93 to 6.41 with not related to the decay of 210 Pb.
    Matched MeSH terms: Radioisotopes
  5. Fulltext Effects of sample density in the determination of radionuclides by gamma spectrometry
    Omar, M., Laili, Z.
    Journal of Nuclear and Related Technologies, 2005;2005(2):15-22.
    MyJurnal
    The effect of sample density in the determination of radionuclides by gamma spectrometry was studied using two multinuclide standard sources of different densities. The self absorption corrections due to differences in sample matrix densities were estimated. The corrections were used in the analysis food and soil samples having packing densities between 0.2 – 1.6g/ml.
    Matched MeSH terms: Radioisotopes
  6. Fulltext Preliminary study on the effects of sample density in activities determination of 137Cs using gamma spectrometry counting system
    Yii, Mei Wo, Zaharudin Ahmad
    Journal of Nuclear and Related Technologies, 2005;2005(2):41-46.
    MyJurnal
    Gamma Spectrometry Counting System requires similar counting geometries for the calibration source, reference material and samples. The objectives of this study were to find out the effects of the sample density on 137 Cs activities measurement and propose reasonable corrections. Studies found that the activity of the samples is decreasing when the density of samples increased. Therefore, in order to have a more accurate estimation of samples activities; density corrections should be done either by performs mathematical corrections using equation or by increasing the expanded uncertainty when sample densities deviated from calibration source.
    Matched MeSH terms: Cesium Radioisotopes
  7. Fulltext Long-term responses of rainforest erosional systems at different spatial scales to selective logging and climatic change
    Walsh RP, Bidin K, Blake WH, Chappell NA, Clarke MA, Douglas I, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3340-53.
    PMID: 22006973 DOI: 10.1098/rstb.2011.0054
    Long-term (21-30 years) erosional responses of rainforest terrain in the Upper Segama catchment, Sabah, to selective logging are assessed at slope, small and large catchment scales. In the 0.44 km(2) Baru catchment, slope erosion measurements over 1990-2010 and sediment fingerprinting indicate that sediment sources 21 years after logging in 1989 are mainly road-linked, including fresh landslips and gullying of scars and toe deposits of 1994-1996 landslides. Analysis and modelling of 5-15 min stream-suspended sediment and discharge data demonstrate a reduction in storm-sediment response between 1996 and 2009, but not yet to pre-logging levels. An unmixing model using bed-sediment geochemical data indicates that 49 per cent of the 216 t km(-2) a(-1) 2009 sediment yield comes from 10 per cent of its area affected by road-linked landslides. Fallout (210)Pb and (137)Cs values from a lateral bench core indicate that sedimentation rates in the 721 km(2) Upper Segama catchment less than doubled with initially highly selective, low-slope logging in the 1980s, but rose 7-13 times when steep terrain was logged in 1992-1993 and 1999-2000. The need to keep steeplands under forest is emphasized if landsliding associated with current and predicted rises in extreme rainstorm magnitude-frequency is to be reduced in scale.
    Matched MeSH terms: Cesium Radioisotopes/analysis; Lead Radioisotopes/analysis
  8. Concentration of radiocaesium 137Cs and 134Cs in sediments of the Malaysian marine environment
    Yii MW, Zaharudin A, Norfaizal M
    Appl Radiat Isot, 2007 Dec;65(12):1389-95.
    PMID: 17697782
    The concentrations of 137Cs and 134Cs in Malaysian marine sediments were measured by gamma-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyzer. In general, the 137Cs concentration in Malaysian marine sediments has been found to be very low and less than 5 Bq/kg dry weight with the exception of those from a few sampling locations. The concentration of 134Cs was found to be less than the minimum detectable activity for the measuring condition used. Data reported in this paper were found to be comparable with results from within the region and thus can be used as reference data for the country.
    Matched MeSH terms: Potassium Radioisotopes
  9. An overview of current knowledge concerning the health and environmental consequences of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident
    Aliyu AS, Evangeliou N, Mousseau TA, Wu J, Ramli AT
    Environ Int, 2015 Dec;85:213-28.
    PMID: 26425805 DOI: 10.1016/j.envint.2015.09.020
    Since 2011, the scientific community has worked to identify the exact transport and deposition patterns of radionuclides released from the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan. Nevertheless, there still remain many unknowns concerning the health and environmental impacts of these radionuclides. The present paper reviews the current understanding of the FDNPP accident with respect to interactions of the released radionuclides with the environment and impacts on human and non-human biota. Here, we scrutinize existing literature and combine and interpret observations and modeling assessments derived after Fukushima. Finally, we discuss the behavior and applications of radionuclides that might be used as tracers of environmental processes. This review focuses on (137)Cs and (131)I releases derived from Fukushima. Published estimates suggest total release amounts of 12-36.7PBq of (137)Cs and 150-160PBq of (131)I. Maximum estimated human mortality due to the Fukushima nuclear accident is 10,000 (due to all causes) and the maximum estimates for lifetime cancer mortality and morbidity are 1500 and 1800, respectively. Studies of plants and animals in the forests of Fukushima have recorded a range of physiological, developmental, morphological, and behavioral consequences of exposure to radioactivity. Some of the effects observed in the exposed populations include the following: hematological aberrations in Fukushima monkeys; genetic, developmental and morphological aberrations in a butterfly; declines in abundances of birds, butterflies and cicadas; aberrant growth forms in trees; and morphological abnormalities in aphids. These findings are discussed from the perspective of conservation biology.
    Matched MeSH terms: Cesium Radioisotopes/analysis; Iodine Radioisotopes/analysis
  10. Thermoluminescence dating analysis at the site of an ancient brick structure at Pengkalan Bujang, Malaysia
    Sabtu SN, Mahat RH, Amin YM, Price DM, Bradley DA, Maah MJ
    Appl Radiat Isot, 2015 Nov;105:182-187.
    PMID: 26319091 DOI: 10.1016/j.apradiso.2015.08.024
    Bujang Valley is a well-known historical complex found in the north-west of peninsular Malaysia; more than 50 ancient monuments and hundreds of artefacts have been discovered throughout the area. The discovery of these suggests Bujang Valley to have been an important South East Asian trading centre over the period from the 10th to 14th centuries. Present work concerns thermoluminescence (TL) dating analysis of shards collected from a historic monument located at Pengkalan Bujang in Bujang Valley. All the shards were prepared using the fine grain technique and the additive dose method was applied in determining the paleodose of each shard. The annual dose rate was obtained by measuring the concentration of naturally occurring radionuclides (U, Th and K) in the samples and their surroundings. The TL ages of the shards were found to range between 330±21 years and 920±69 years, indicative of the last firing of the bricks and tiles from which the shards originated, some dating back to the period during which the historical complex remained active.
    Matched MeSH terms: Radioisotopes
  11. Radionuclides transfer from soil-to-tea leaves and concomitant doses to the Malaysian populace
    Khandaker MU, Mokhrizal NFB, Shuaibu HK, Sani SFA, Alzimami K, Bradley DA, et al.
    Appl Radiat Isot, 2024 Oct;212:111474.
    PMID: 39146808 DOI: 10.1016/j.apradiso.2024.111474
    One of the most well-liked energizing drinks is now tea, which is primarily used in Malaysia. The natural radioactivity in the associated soils where tea plants are cultivated plays a major role in determining the presence of radionuclides in tea leaves. The present study assesses the transfer of radionuclides from soil-to-tea leaves and then estimates the committed effective doses through tea consumption. Tea leaves and the associated soils were obtained from the largest tea plantation area, which is located in the Cameron Highlands, Malaysia. The marketed tea leaves in powdered form were obtained from the supermarkets in Kuala Lumpur. HPGe gamma-ray spectrometry was used to determine the prevailing concentrations of long-lived radioactive materials in tea leaves. Activity concentrations of 226Ra, 232Th, and 40K in tea soils ranged from 49 to 101.7 Bq kg-1, 74.5-124.1 Bq kg-1 and 79.6-423.2 Bq kg-1, respectively, while the respective values in tea leaves are 14.4-23.8 Bq kg-1, 12.9-29.5 Bq kg-1 and 297-387.5 Bq kg-1. Transfer factors of radionuclides showed typical values (<1.0) except for the 40K. The threshold tea consumption rates suggest that one should not consume more than 67 g of tea leaves per day (around 4 g of tea leaves are needed for making 1 cup of tea, so 17 cups per day) to avoid negative health effects. Committed effective doses due to tea consumption are found to be lower (5.18-6.08 μSv y-1) than the United Nations Scientific Committee on the Effects of Atomic Radiation (2000) reference dose guidance limit of 290 μSv y-1 for foodstuffs; however, it should be noted that the guidance limit is recommended for all foodstuffs collectively. Providing data on natural radioactivity in tea leaves grown in Malaysia, this study may help people manage a healthy lifestyle.
    Matched MeSH terms: Potassium Radioisotopes/analysis; Radioisotopes/analysis
  12. The Potential of Radiolabeled Bisphosphonates in SPECT and PET for Bone Imaging
    Ashhar Z, Ahmad Fadzil MF, Hassan H, Othman MF, Md Hassan MB, Chun Vui VY, et al.
    Curr Med Imaging, 2024;20:e15734056270935.
    PMID: 38874043 DOI: 10.2174/0115734056270935231113035620
    Skeletal-related events due to bone metastases can be prevented by early diagnosis using radiological or nuclear imaging techniques. Nuclear medicine techniques such as Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) have been used for diagnostic imaging of bone for decades. Although it is widely recognized that conventional diagnostic imaging techniques such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) have high sensitivity, low cost and wide availability, the specificity of both techniques is rather low compared to nuclear medicine techniques. Nuclear medicine techniques, on the other hand, have improved specificity when introduced as a hybrid imaging modality, as they can combine physiological and anatomical information. Two main radiopharmaceuticals are used in nuclear medicine: [99mTc]-methyl diphosphonate ([99mTc]Tc-MDP) from the generator and [18F]sodium fluoride ([18F]NaF) from the cyclotron. The former is used in SPECT imaging, while the latter is used in PET imaging. However, recent studies show that the role of radiolabeled bisphosphonates with gallium-68 (68Ga) and fluorine-18 (18F) may have a potential role in the future. This review, therefore, presents and discusses the brief method for producing current and future potential radiopharmaceuticals for bone metastases.
    Matched MeSH terms: Gallium Radioisotopes
  13. The quantification of PET-CT radiotracers to determine minimal scan time using quadratic formulation
    Said MA, Musarudin M, Zulkaffli NF
    Ann Nucl Med, 2020 Dec;34(12):884-891.
    PMID: 33141408 DOI: 10.1007/s12149-020-01543-x
    OBJECTIVE: 18F is the most extensively used radioisotope in current clinical practices of PET imaging. This selection is based on the several criteria of pure PET radioisotopes with an optimum half-life, and low positron energy that contributes to a smaller positron range. In addition to 18F, other radioisotopes such as 68Ga and 124I are currently gained much attention with the increase in interest in new PET tracers entering the clinical trials. This study aims to determine the minimal scan time per bed position (Tmin) for the 124I and 68Ga based on the quantitative differences in PET imaging of 68Ga and 124I relative to 18F.

    METHODS: The European Association of Nuclear Medicine (EANM) procedure guidelines version 2.0 for FDG-PET tumor imaging has adhered for this purpose. A NEMA2012/IEC2008 phantom was filled with tumor to background ratio of 10:1 with the activity concentration of 30 kBq/ml ± 10 and 3 kBq/ml ± 10% for each radioisotope. The phantom was scanned using different acquisition times per bed position (1, 5, 7, 10 and 15 min) to determine the Tmin. The definition of Tmin was performed using an image coefficient of variations (COV) of 15%.

    RESULTS: Tmin obtained for 18F, 68Ga and 124I were 3.08, 3.24 and 32.93 min, respectively. Quantitative analyses among 18F, 68Ga and 124I images were performed. Signal-to-noise ratio (SNR), contrast recovery coefficients (CRC), and visibility (VH) are the image quality parameters analysed in this study. Generally, 68Ga and 18F gave better image quality as compared to 124I for all the parameters studied.

    CONCLUSION: We have defined Tmin for 18F, 68Ga and 124I SPECT CT imaging based on NEMA2012/IEC2008 phantom imaging. Despite the long scanning time suggested by Tmin, improvement in the image quality is acquired especially for 124I. In clinical practice, the long acquisition time, nevertheless, may cause patient discomfort and motion artifact.

    Matched MeSH terms: Fluorine Radioisotopes/chemistry; Gallium Radioisotopes/chemistry; Iodine Radioisotopes/chemistry
  14. Dosimetric characterisation of the optically-stimulated luminescence dosimeter in cobalt-60 high dose rate brachytherapy system
    Rejab M, Wong JHD, Jamalludin Z, Jong WL, Malik RA, Wan Ishak WZ, et al.
    Australas Phys Eng Sci Med, 2018 Jun;41(2):475-485.
    PMID: 29756166 DOI: 10.1007/s13246-018-0647-6
    This study investigates the characteristics and application of the optically-stimulated luminescence dosimeter (OSLD) in cobalt-60 high dose rate (HDR) brachytherapy, and compares the results with the dosage produced by the treatment planning system (TPS). The OSLD characteristics comprised linearity, reproducibility, angular dependence, depth dependence, signal depletion, bleaching rate and cumulative dose measurement. A phantom verification exercise was also conducted using the Farmer ionisation chamber and in vivo diodes. The OSLD signal indicated a supralinear response (R2 = 0.9998). It exhibited a depth-independent trend after a steep dose gradient region. The signal depletion per readout was negligible (0.02%), with expected deviation for angular dependence due to off-axis sensitive volume, ranging from 1 to 16%. The residual signal of the OSLDs after 1 day bleached was within 1.5%. The accumulated and bleached OSLD signals had a standard deviation of ± 0.78 and ± 0.18 Gy, respectively. The TPS was found to underestimate the measured doses with deviations of 5% in OSLD, 17% in the Farmer ionisation chamber, and 7 and 8% for bladder and rectal diode probes. Discrepancies can be due to the positional uncertainty in the high-dose gradient. This demonstrates a slight displacement of the organ at risk near the steep dose gradient region will result in a large dose uncertainty. This justifies the importance of in vivo measurements in cobalt-60 HDR brachytherapy.
    Matched MeSH terms: Cobalt Radioisotopes/chemistry*
  15. Characterization of MOSkin detector for in vivo dose verification during Cobalt-60 high dose-rate intracavitary brachytherapy
    Jamalludin Z, Jong WL, Abdul Malik R, Rosenfeld A, Ung NM
    Phys Med, 2019 Feb;58:1-7.
    PMID: 30824140 DOI: 10.1016/j.ejmp.2019.01.010
    In vivo dosimetry in high dose-rate (HDR) intracavitary brachytherapy (ICBT) is important for assessing the true dose received by surrounding organs at risk during treatment. It also serves as part of the treatment delivery quality assurance and verification program with the use of a suitable dosimeter. Such a dosimeter should be characterized under brachytherapy conditions before clinical application to ensure the accuracy of in vivo measurement. In this study, a MOSFET-based detector, MOSkin, was calibrated and characterized under HDR Cobalt-60 (Co-60) brachytherapy source. MOSkin possessed the major advantages of having small physical and dosimetric sizes of 4.8 × 10-6 mm3 with the ability to provide real-time measurements. Using solid water and polymethyl methacrylate (PMMA) phantom, the detectors' reproducibility, linearity, angular and distance dependency was tested for its suitability as an in vivo detector. Correction factors to account for differences in depth measurements were determined. The MOSkin detector showed a reliable response when tested under Co-60 brachytherapy range of doses with an excellent linearity of R2 = 0.9997 and acceptable reproducibility. A phantom verification study was also conducted to verify the differences between MOSkin responses and treatment planning (TPS) calculated doses. By taking into account several correction factors, deviations ranging between 0.01 and 0.4 Gy were found between MOSkin measured and TPS doses at measurement distance of 20-55 mm. The use of MOSkin as the dosimeter of choice for in vivo dosimetry under Co-60 brachytherapy condition is feasible.
    Matched MeSH terms: Cobalt Radioisotopes/therapeutic use*
  16. Study of Primordial 226Ra, 228Ra, and 40K Concentrations in Dietary Palm Dates and Concomitant Radiological Risk
    Khandaker MU, Shuaibu HK, Alklabi FAA, Alzimami KS, Bradley DA
    Health Phys, 2019 06;116(6):789-798.
    PMID: 30889102 DOI: 10.1097/HP.0000000000001042
    The presence of natural radionuclides in the food chain point to a need to assess concentration levels and concomitant radiological risk. Highly popular and forming a staple part of the diet in North Africa, the Arabian Peninsula, and West Asia, palm dates growing naturally there have even greater marketability than simple satisfaction of domestic demand, the palm dates representing a valuable export item. Accurate knowledge of the levels of natural radioactivity in the fruit is thus of importance. In this study, using high-purity germanium gamma-ray spectrometry, quantification has been made of natural radionuclide concentrations in imported dates originating from Iran, Saudi Arabia, and Tunisia. Sample analyses reveal respective mean activity concentrations of 1.4 ± 0.3, 0.8 ± 0.4, and 186 ± 9 Bq kg dry weight for Ra, Ra, and K. For each nuclide, the mean concentration varies little between the dates of the three represented regions. The estimated committed effective dose resulting from the consumption of date fruits for a typical adult was found to be 29.9 μSv y, well below the global internal dose of 290 μSv y assessed by the United Nations Scientific Committee on the Effects of Atomic Radiation to be due to food and water intake. Similarly, the excess lifetime cancer risk due to naturally occurring radioactive material exposure via date fruit consumption is seen to be below the International Commission on Radiological Protection cancer risk factor of 2.5 × 10 based on the additional annual dose limit of 1 mSv for a member of the general public. The results show no significant uptake in the analyzed date fruits.
    Matched MeSH terms: Potassium Radioisotopes/analysis*
  17. Asian dust increases radiocesium retention ability of serpentine soils in Japan
    Nakao A, Tomita M, Wagai R, Tanaka R, Yanai J, Kosaki T
    J Environ Radioact, 2019 Aug;204:86-94.
    PMID: 30986719 DOI: 10.1016/j.jenvrad.2019.03.028
    Radiocesium (RCs) is selectively adsorbed on interlayer sites of weathered micaceous minerals, which can reduce the mobility of RCs in soil. Therefore, soils developed from mica-deficient materials (e.g. serpentine soils) may have a higher risk of soil-to-plant transfer of RCs. Soils were collected from three serpentine soil profiles; Udepts in Oeyama, Japan, and Udepts and Udox in Kinabalu, Malaysia. Soil was sampled every 3 cm from 0 to 30 cm depth and sieved to isolate soil particles of ≤20 μm diameter for the assessment of radiocesium interception potential (RIP) after a series of pretreatments. One subset was treated with H2O2 to remove organic matter (OM). Another subset was further treated with hot sodium citrate to remove hydroxy-Al polymers (Al(OH)x). RIPuntreated was <0.4 mol kg-1 whereas mica-K content was <0.02% by weight for ≤20-μm soil particles from Udepts and Udox in Kinabalu, Malaysia, values as low as those of non-micaceous minerals (e.g. kaolinite and smectite). Neither OM nor Al(OH)x removal resulted in a large increase in RIP value for these soils. These results clearly indicated that serpentine soils in Malaysia have very few RCs selective adsorption sites due to the absence of micaceous minerals. In contrast, soil from Udepts in Oeyama, Japan showed average RIPuntreated of 5.6 mol kg-1 and mica-K content of 0.72% by weight for the ≤20-μm particles. Furthermore, the RIP value was significantly increased to an average of 22.5 mol kg-1 after removing both OM and Al(OH)x. These results strongly suggest that weathered micaceous minerals primarily control the ability to retain RCs. These micaceous minerals cannot originate from serpentine minerals, and are probably incorporated as an exotic material, such as Asian dust. This hypothesis is supported by the δ18O value of quartz isolated from the ≤20-μm soil particles from Oeyama, Japan (+16.13‰±0.11‰), very similar to that of Asian dust. In conclusion, serpentine soils in Japan may exhibit a reduced risk of soil-to-plant transfer of RCs due to the historical deposition of Asian dust.
    Matched MeSH terms: Cesium Radioisotopes/analysis*
  18. ASSESSMENT OF NATURALLY OCCURRING RADIONUCLIDES IN MALAYSIA'S BUILDING MATERIALS
    Abdullahi S, Ismail AF, Samat S
    Radiat Prot Dosimetry, 2019 Dec 31;186(4):520-523.
    PMID: 31034551 DOI: 10.1093/rpd/ncz125
    The activity concentrations of 226Ra, 232Th and 40K radionuclides from common building materials used by Malaysian people for construction purposes were studied using High-Purity Germanium (HPGe) detector. The measured activity concentrations of the aforementioned radionuclides range from 10 ± 1 Bq kg-1 (limestone) to 155 ± 61 Bq kg-1 (feldspar), 12 ± 3 Bq kg-1 (limestone) to 274 ± 8 Bq kg-1 (kaolin) and 62 ± 19 Bq kg-1 (limestone) to 1114 ± 20 Bq kg-1 (pottery stone) for 226Ra, 232Th and 40K, respectively. The measured activity concentrations of the natural radionuclides reported herein were found to be in accordance with other previous studies. In general, the activity concentration of the natural radionuclides revealed that all the determined values were below the recommended limit.
    Matched MeSH terms: Potassium Radioisotopes/analysis*
  19. Fulltext Radiation doses to patient's relatives following radioiodine therapy
    Sulaiman BT, Clarke SE
    Med J Malaysia, 1996 Mar;51(1):131-3.
    PMID: 10967992
    A total of 10 volunteers were monitored for radiation doses, whose spouses were given radio-iodine (131I) orally. Nine of the spouses were given radio-iodine for Graves' disease and one for thyroid carcinoma. It was found that the highest radiation dose received by the volunteer was only 13.5% of the annual dose limit for individual members of the public. Hence, patients treated with radio-iodine do not pose a significant radiation hazard to the public.
    Matched MeSH terms: Iodine Radioisotopes/therapeutic use*
  20. Behaviors of 323Th, 238U, 228Ra and 226Ra on combustion of crude oil terminal sludge
    Puad HA, Noor MY
    J Environ Radioact, 2004;73(3):289-305.
    PMID: 15050361
    Crude oil terminal sludge contains technologically enhanced naturally occurring radionuclides such as (232)Th, (238)U, (228)Ra and (226)Ra, thus cannot be disposed of freely without proper control. The current method of disposal, such as land farming and storing in plastic drums is not recommended because it will have a long-term impact on the environment. Due to its organic nature, there is a move to treat this sludge by thermal methods such as incineration. This study has been carried out to determine the behaviors of (232)Th, (238)U, (228)Ra and (226)Ra present in the sludge during combustion at a certain temperature and time. The percentage of volatilization was found to vary between 2% and 70%, (238)U was the most volatile in comparison with (232)Th, (228)Ra and (226)Ra. (238)U is found to be significantly volatilized above 500 degrees C, and might reach maximum volatilization at above 700 degrees C. A mathematical model was developed to predict the percentage of volatilization of (232)Th, (238)U, (228)Ra and (226)Ra contained in the sludge. With this known percentage of volatilization, the concentration of (232)Th, (238)U, (228)Ra and (226)Ra present in the bottom and filter ashes can be calculated.
    Matched MeSH terms: Radioisotopes/analysis*
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