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  1. Fulltext Neutron-activated biodegradable samarium-153 acetylacetonate-poly-L-lactic acid microspheres for intraarterial radioembolization of hepatic tumors
    Wong YH, Tan HY, Kasbollah A, Abdullah BJJ, Acharya RU, Yeong CH
    World J Exp Med, 2020 Mar 30;10(2):10-25.
    PMID: 32266125 DOI: 10.5493/wjem.v10.i2.10
    BACKGROUND: Liver cancer is the 6th most common cancer in the world and the 4th most common death from cancer worldwide. Hepatic radioembolization is a minimally invasive treatment involving intraarterial administration of radioembolic microspheres.

    AIM: To develop a neutron-activated, biodegradable and theranostics samarium-153 acetylacetonate (153SmAcAc)-poly-L-lactic acid (PLLA) microsphere for intraarterial radioembolization of hepatic tumors.

    METHODS: Microspheres with different concentrations of 152SmAcAc (i.e., 100%, 150%, 175% and 200% w/w) were prepared by solvent evaporation method. The microspheres were then activated using a nuclear reactor in a neutron flux of 2 × 1012 n/cm2/s1, converting 152Sm to Samarium-153 (153Sm) via152Sm (n, γ) 153Sm reaction. The SmAcAc-PLLA microspheres before and after neutron activation were characterized using scanning electron microscope, energy dispersive X-ray spectroscopy, particle size analysis, Fourier transform infrared spectroscopy, thermo-gravimetric analysis and gamma spectroscopy. The in-vitro radiolabeling efficiency was also tested in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.

    RESULTS: The SmAcAc-PLLA microspheres with different SmAcAc contents remained spherical before and after neutron activation. The mean diameter of the microspheres was about 35 µm. Specific activity achieved for 153SmAcAc-PLLA microspheres with 100%, 150%, 175% and 200% (w/w) SmAcAc after 3 h neutron activation were 1.7 ± 0.05, 2.5 ± 0.05, 2.7 ± 0.07, and 2.8 ± 0.09 GBq/g, respectively. The activity of per microspheres were determined as 48.36 ± 1.33, 74.10 ± 1.65, 97.87 ± 2.48, and 109.83 ± 3.71 Bq for 153SmAcAc-PLLA microspheres with 100%, 150%, 175% and 200% (w/w) SmAcAc. The energy dispersive X-ray and gamma spectrometry showed that no elemental and radioactive impurities present in the microspheres after neutron activation. Retention efficiency of 153Sm in the SmAcAc-PLLA microspheres was excellent (approximately 99%) in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.

    CONCLUSION: The 153SmAcAc-PLLA microsphere is potentially useful for hepatic radioembolization due to their biodegradability, favorable physicochemical characteristics and excellent radiolabeling efficiency. The synthesis of the formulation does not involve ionizing radiation and hence reducing the complication and cost of production.

    Matched MeSH terms: Spectrometry, Gamma
  2. Perubahan Kepekatan Aktiviti Ra-226 dan Ra-228 di Sepanjang Sungai Langat dan Sungai Semenyih, Selangor (Variation in Concentration of Ra-226 and Ra-228 Activities Along Langat and Semenyih River, Selangor)
    Phuah CS, Che Abd Rahim Mohamed, Zaharuddin Ahmad
    Sains Malaysiana, 2004;33.
    Concentration of Ra-226 and Ra-228 activities in water and sediment samples were measured using the Liquid Scintillation Counter (LSC) and High Purity Germanium Gamma Spectrometry (HPGe). respectively. Concentrations of Ra-226 activity in sediment samples range from 18.93 Bg/ kg to 236.06 Bq/kg and for Ra-228 activity range from 12.59 Bg/kg to 410.60 Bq/kg. Meanwhile, concentrations of Ra-226 activity obtained in water samples range from 0.064 Bg/L to 0.199 Bq/L. These data indicate, that the distribution of Ra-228 and Ra-226 in the study area were varied from one sampling stations to another and is probably related to the contents of suspended particles.
    Penentuan kepekatan aktiviti Ra-226 dan Ra-228 dalam sampel air dan sedimen dilakukan masing-masing dengan Pembilang Sintilasi Cecair (LSC) dan Spektrometri Gamma Germanium Lampau Tulen (HPGe). Kepekatan aktiviti Ra-226 dalam sampel sedimen adalah berjulat dari 18.93 Bg/kg hingga 236.06 Bq/kg dan kepekatan aktiviti Ra-228 berjulat dari 12.59 Bg/kg hingga 410.60 Bq/kg. Kepekatan aktiviti Ra-226 dalam sampel air yang diperolehi pula berjulat dari 0.064 Bg/L hingga 0.199 Bq/L. Ini menunjukkan taburan Ra-228 dan Ra-226 di kawasan kajian adalah berubah mengikut lokasi kajian dan berkemungkinan dipengaruhi oleh sifat kandungan bahan terampai.
    Matched MeSH terms: Spectrometry, Gamma
  3. Activity Determination of 137Cs in NPL’s Ampoule Using a Point Source
    Supian Bin Samat
    Sains Malaysiana, 1997;26.
    The activity of two liquid mixed radionuclide sources in NPL'S standard glass ampoules were determined by gamma-ray spectrometry measurement using a standard point source placed at 38.5 cm axially above the detector. A radio nuclide 137Cs was chosen, Results obtained were within 3% agreement with the calculated value. The same degree of deviation was obtained when the NPL standard source of equal geometry, chemical composition and density was used.
    Keaktifan dua sumber radionuklid campuran cecair yang terkandung dalam bekas kaca piawai NPL ditentukan dengan kaedah pengukuran spektrometri sinar-gama menggunakan satu sumber titik piawai diletakkan pada 38.5 em di atas pengesan, Satu sumber radionuklid 137Cs dipilih. Keputusan yang diperoleh bersetuju dalam lingkungan 3% dengan nilai yang dikira. Darjah simpangan yang sama diperoleh apabila sumber piawai NPL yang sama dari segi geometri, komposisi kimia dan ketumpatan digunakan,
    Matched MeSH terms: Spectrometry, Gamma
  4. Determination of peak-to-total ratio versus gamma-ray energy of a HPGe detector
    Supian Samat, Lee YK
    Sains Malaysiana, 2006;35:57-60.
    This note describes a method for the determination of the peak-to-total ratio, P/T versus gamma-ray energy of range 59.54-1836.03 keV of a HPGe detector. Results show that this ratio decreases with energy. To check the validity of these results, two approaches of results comparison, namely with the ratio reported by Cesana and Terrani in year 1989 and with the shape of total efficiency reported by Debertin and Helmer in year 1988 were taken. lt is shown that this method gives satisfactory results since the obtained values of P/T and the shape of the total efficiency curve were in good agreement with the reported works. The precautional step that need to be taken when dealing with energy 59.54 keV 241Am source and the reason for taking the total efficiency as the evaluation tool are given.
    Matched MeSH terms: Spectrometry, Gamma
  5. Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia
    Alnour IA, Wagiran H, Ibrahim N, Hamzah S, Elias MS, Laili Z, et al.
    Radiat Prot Dosimetry, 2014 Jan;158(2):201-7.
    PMID: 23965286 DOI: 10.1093/rpd/nct206
    The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.
    Matched MeSH terms: Spectrometry, Gamma/methods*
  6. Measurement of ²³⁸U,²³²Th and ⁴⁰K in boreholes at Gosa and Lugbe, Abuja, north central Nigeria
    Maxwell O, Wagiran H, Ibrahim N, Lee SK, Sabri S
    Radiat Prot Dosimetry, 2013 Dec;157(2):271-7.
    PMID: 23754832 DOI: 10.1093/rpd/nct140
    The purpose of this project is to evaluate the suitability of different sites as locations for obtaining underground water for consumption. The analysis of ²³⁸U, ²³²Th and ⁴⁰K from rock samples from each layer of borehole at a depth of ∼50 m at Site A borehole, S3L1-S3L6 in Gosa and 40 m at Site B borehole, S4L1-S4L5 in Lugbe, Abuja, north central Nigeria is presented. The gamma-ray spectrometry was carried out using a high-purity germanium detector coupled to a computer-based high-resolution multichannel analyzer. The activity concentrations at Site A borehole for ²³⁸U have a mean value of 26 ± 3, ranging from 23 ± 2 to 30 ± 3 Bq kg⁻¹, ²³²Th a mean value of 63 ± 5, ranging from 48 ± 4 to 76 ± 6 Bq kg⁻¹ and ⁴⁰K a mean value of 573 ± 72, ranging from 437 ± 56 to 821 ± 60 Bq kg⁻¹. The activity concentrations at Site B borehole for ²³⁸U have a mean value of 20 ± 2, ranging from 16 ± 2 to 23 ± 2 Bq kg⁻¹, ²³²Th a mean value of 46 ± 4, ranging from 43 ± 4 to 49 ± 4 Bq kg⁻¹, ⁴⁰K a mean value of 915 ± 116 and ranging from 817 ± 103 Bq kg⁻¹ to 1011 ± 128 Bq kg⁻¹. It is noted that the higher activity concentrations of ²³²Th and ²³⁸U are found in Site A at Gosa. Site B has lower radioactivity, and it is recommended that both sites are suitable for underground water consumption.
    Matched MeSH terms: Spectrometry, Gamma
  7. Radiometric analysis of construction materials using HPGe gamma-ray spectrometry
    Khandaker MU, Jojo PJ, Kassim HA, Amin YM
    Radiat Prot Dosimetry, 2012 Nov;152(1-3):33-7.
    PMID: 22887119 DOI: 10.1093/rpd/ncs145
    Concentrations of primordial radionuclides in common construction materials collected from the south-west coastal region of India were determined using a high-purity germanium gamma-ray spectrometer. Average specific activities (Bq kg(-1)) for (238)U((226)Ra) in cement, brick, soil and stone samples were obtained as 54 ± 13, 21 ± 4, 50 ± 12 and 46 ± 8, respectively. Respective values of (232)Th were obtained as 65 ± 10, 21 ± 3, 58 ± 10 and 57 ± 12. Concentrations of (40)K radionuclide in cement, brick, soil and stone samples were found to be 440 ± 91, 290 ± 20, 380 ± 61 and 432 ± 64, respectively. To evaluate the radiological hazards, radium equivalent activity, various hazard indices, absorbed dose rate and annual effective dose have been calculated, and compared with the literature values. Obtained data could be used as reference information to assess any radiological contamination due to construction materials in future.
    Matched MeSH terms: Spectrometry, Gamma/methods*
  8. NATURAL RADIONUCLIDES IN SOIL AND ROOT VEGETABLES IN MALAYSIA: TRANSFER FACTORS AND DOSE ESTIMATES
    Al Mutairi AMM, Kabir NA
    Radiat Prot Dosimetry, 2020 Jun 12;188(1):47-55.
    PMID: 31711202 DOI: 10.1093/rpd/ncz256
    Tapioca and sweet potato are the fourth and fifth most consumed crops in Malaysia. The activity concentrations of natural radionuclides in these vegetables were assessed from two regions in Malaysia (Kedah and Penang) along with soil samples using gamma ray spectroscopy. The transfer factors of 226Ra, 232Th and 40K from soil to vegetables were calculated, and a dose assessment was performed. The activity concentrations of 226Ra, 232Th and 40K in soil samples did not show a significant variation with the regions investigated, and the average values obtained, in Bq/kg, (±SD) were as follows: 80 ± 41, 56 ± 12, 516 ± 119, respectively. The respective average activity concentrations in vegetables were as follows, in Bq/kg: (±SD) 2.0 ± 0.5, 6 ± 2, 153 ± 49. The corresponding transfer factors were calculated to be 0.03, 0.11 and 0.31 for 226Ra, 232Th and 40K, respectively. The average annual effective doses due to the exposure from soil and ingestion of vegetables were found to lie within the worldwide ranges.
    Matched MeSH terms: Spectrometry, Gamma
  9. A STUDY OF NATURAL RADIOACTIVITY IN SOME BUILDING MATERIALS IN NIGERIA
    Maxwell O, Emmanuel JS, Olusegun AO, Cyril EO, Ifeanyi AT, Embong Z
    Radiat Prot Dosimetry, 2019 May 01;183(3):332-335.
    PMID: 30085254 DOI: 10.1093/rpd/ncy121
    Building materials of different brands were assessed for the concentrations of 226Ra, 232Th and 40K using HPGe detector. The activity concentrations in the measured samples ranged from 27 ± 8 to 82 ± 8 Bq kg-1 for 226Ra, 41 ± 4 to 101 ± 8 Bq kg-1 for 232Th and 140 ± 8 to 940 ± 19 Bq kg-1 for 40K, respectively. The Radium equivalent (Raeq) activity from the samples was found to be <370 Bq kg-1 as the recommended value for construction materials. This study will set a baseline data for significant standards on radiation exposure of the measured radionuclides in the selected building materials used in Nigeria.
    Matched MeSH terms: Spectrometry, Gamma
  10. ASSESSMENT OF NATURAL RADIOACTIVITY IN MAIZE AND ESTIMATION OF CONCOMITANT DOSE TO NIGERIAN VIA INGESTION PATHWAY
    Yarima MH, Khandaker MU, Nadhiya A, Olatunji MA
    Radiat Prot Dosimetry, 2019 Oct 01;184(3-4):359-362.
    PMID: 31089715 DOI: 10.1093/rpd/ncz115
    Uranium, thorium and potassium are the most abundant naturally occurring radioactive materials (NORMs) found in soils and other environmental media including foodstuffs. Since the human exposures to NORMs is an unavoidable phenomenon, in such a way that they can easily find their way to human being via food chain, detailed knowledge on their presence in foodstuffs is necessary to assess the radiation dose to the population. Thus, the present study concerns the assessment of natural radioactivity in maize, a staple foodstuff for Nigerian, via HPGe gamma-ray spectrometry. Activity concentrations (Bq/kg) in the maize samples were found to be in the range of 6.1 ± 0.6-8.2 ± 1.3, 2.2 ± 0.4-5.1 ± 0.7 and 288 ± 16-401 ± 24 for 226Ra, 232Th and 40K, respectively. Measured data for 226Ra and 232Th show below the world average values of 67 Bq/kg and 82 Bq/kg, respectively, while the activity of 40K exceeds the global average of 310 Bq/kg. The annual effective dose via the maize consumption was found to be far below the UNSCEAR recommended ingestion dose limit of 290 μSv/y, and the estimated lifetime cancer risk show lower than the ICRP (1991) cancer risk factor of 2.5 × 10-3 based on the additional annual dose limit of 1 mSv for general public, thus pose no adverse health risk to the Nigerian populace.
    Matched MeSH terms: Spectrometry, Gamma
  11. Fulltext The presence of radioactive heavy minerals in prospecting trenches and concomitant occupational exposure
    Hanfi MYM, Masoud MS, Sayyed MI, Khandaker MU, Faruque MRI, Bradley DA, et al.
    PLoS One, 2021;16(3):e0249329.
    PMID: 33788889 DOI: 10.1371/journal.pone.0249329
    Uranium, perhaps the most strategically important component of heavy minerals, finds particular significance in the nuclear industry. In prospecting trenches, the radioactivity of 238U and 232Th provides a good signature of the presence of heavy minerals. In the work herein, the activity concentrations of several key primordial radionuclides (238U, 232Th, and 40K) were measured in prospecting trenches (each of the latter being of approximately the same geometry and physical situation). All of these are located in the Seila area of the South Eastern desert of Egypt. A recently introduced industry standard, the portable hand-held RS-230 BGO gamma-ray spectrometer (1024 channels) was employed in the study. Based on the measured data, the trenches were classified as either non-regulated (U activity less than 1000 Bq kg-1) or regulated (with 238U activity more than 1000 Bq kg-1). Several radiological hazard parameters were calculated, statistical analysis also being performed to examine correlations between the origins of the radionuclides and their influence on the calculated values. While the radioactivity and hazard parameters exceed United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) guided limits, the mean annual effective doses of 0.49 and 1.4 mSv y-1 in non-regulated and regulated trenches respectively remain well below the International Commission on Radiological Protection (ICRP) recommended 20 mSv/y maximum occupational limit. This investigation reveals that the studied area contains high uranium content, suitable for extraction of U-minerals for use in the nuclear fuel cycle.
    Matched MeSH terms: Spectrometry, Gamma
  12. Fulltext Assessment of Natural Radioactivity Levels and Potential Radiological Risks of Common Building Materials Used in Bangladeshi Dwellings
    Asaduzzaman K, Mannan F, Khandaker MU, Farook MS, Elkezza A, Amin YB, et al.
    PLoS One, 2015;10(10):e0140667.
    PMID: 26473957 DOI: 10.1371/journal.pone.0140667
    The concentrations of primordial radionuclides (226Ra, 232Th and 40K) in commonly used building materials (brick, cement and sand), the raw materials of cement and the by-products of coal-fired power plants (fly ash) collected from various manufacturers and suppliers in Bangladesh were determined via gamma-ray spectrometry using an HPGe detector. The results showed that the mean concentrations of 226Ra, 232Th and 40K in all studied samples slightly exceeded the typical world average values of 50 Bq kg(-1), 50 Bq kg(-1) and 500 Bq kg(-1), respectively. The activity concentrations (especially 226Ra) of fly-ash-containing cement in this study were found to be higher than those of fly-ash-free cement. To evaluate the potential radiological risk to individuals associated with these building materials, various radiological hazard indicators were calculated. The radium equivalent activity values for all samples were found to be lower than the recommended limit for building materials of 370 Bq kg(-1), with the exception of the fly ash. For most samples, the values of the alpha index and the radiological hazard (external and internal) indices were found to be within the safe limit of 1. The mean indoor absorbed dose rate was observed to be higher than the population-weighted world average of 84 nGy h(-1), and the corresponding annual effective dose for most samples fell below the recommended upper dose limit of 1 mSv y(-1). For all investigated materials, the values of the gamma index were found to be greater than 0.5 but less than 1, indicating that the gamma dose contribution from the studied building materials exceeds the exemption dose criterion of 0.3 mSv y(-1) but complies with the upper dose principle of 1 mSv y(-1).
    Matched MeSH terms: Spectrometry, Gamma/methods
  13. 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: Spectrometry, Gamma
  14. Fulltext Preparation and In Vitro Evaluation of Neutron-Activated, Theranostic Samarium-153-Labeled Microspheres for Transarterial Radioembolization of Hepatocellular Carcinoma and Liver Metastasis
    Wong YH, Tan HY, Kasbollah A, Abdullah BJJ, Yeong CH
    Pharmaceutics, 2019 Nov 12;11(11).
    PMID: 31718079 DOI: 10.3390/pharmaceutics11110596
    INTRODUCTION: Transarterial radioembolization (TARE) has been proven as an effective treatment for unresectable liver tumor. In this study, neutron activated, 153Sm-labeled microspheres were developed as an alternative to 90Y-labeled microspheres for hepatic radioembolization. 153Sm has a theranostic advantage as it emits both therapeutic beta and diagnostic gamma radiations simultaneously, in comparison to the pure beta emitter, 90Y.

    METHODS: Negatively charged acrylic microspheres were labeled with 152Sm ions through electrostatic interactions. In another formulation, the Sm-labeled microsphere was treated with sodium carbonate solution to form the insoluble 152Sm carbonate (152SmC) salt within the porous structures of the microspheres. Both formulations were neutron-activated in a research reactor. Physicochemical characterization, gamma spectrometry, and radiolabel stability tests were carried out to study the performance and stability of the microspheres.

    RESULTS: The Sm- and SmC-labeled microspheres remained spherical and smooth, with a mean size of 35 µm before and after neutron activation. Fourier transform infrared (FTIR) spectroscopy indicated that the functional groups of the microspheres remained unaffected after neutron activation. The 153Sm- and 153SmC-labeled microspheres achieved activity of 2.53 ± 0.08 and 2.40 ± 0.13 GBq·g-1, respectively, immediate after 6 h neutron activation in the neutron flux of 2.0 × 1012 n·cm-2·s-1. Energy-dispersive X-ray (EDX) and gamma spectrometry showed that no elemental and radioactive impurities were present in the microspheres after neutron activation. The retention efficiency of 153Sm in the 153SmC-labeled microspheres was excellent (~99% in distilled water and saline; ~97% in human blood plasma), which was higher than the 153Sm-labeled microspheres (~95% and ~85%, respectively).

    CONCLUSION: 153SmC-labeled microspheres have demonstrated excellent properties for potential application as theranostic agents for hepatic radioembolization.

    Matched MeSH terms: Spectrometry, Gamma
  15. Fulltext The Effect of Various Waste Materials' Contents on the Attenuation Level of Anti-Radiation Shielding Concrete
    Azeez AB, Mohammed KS, Abdullah MMAB, Hussin K, Sandu AV, Razak RA
    Materials (Basel), 2013 Oct 23;6(10):4836-4846.
    PMID: 28788363 DOI: 10.3390/ma6104836
    Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised (137)Cs and ⁶⁰Co radioactive elements with photon energies of 0.662 MeV for (137)Cs and two energy levels of 1.17 and 1.33 MeV for the ⁶⁰Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10(-3) for (137)Cs and 0.92 ± 1.57 × 10(-3) for ⁶⁰Co. Substantial improvement in attenuation performance by 20%-25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%-30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.
    Matched MeSH terms: Spectrometry, Gamma
  16. Assessment of natural radioactivity and gamma-ray dose in monazite rich black Sand Beach of Penang Island, Malaysia
    Shuaibu HK, Khandaker MU, Alrefae T, Bradley DA
    Mar Pollut Bull, 2017 Jun 15;119(1):423-428.
    PMID: 28342594 DOI: 10.1016/j.marpolbul.2017.03.026
    Activity concentrations of primordial radionuclides in sand samples collected from the coastal beaches surrounding Penang Island have been measured using conventional γ-ray spectrometry, while in-situ γ-ray doses have been measured through use of a portable radiation survey meter. The mean activity concentrations for 226Ra, 232Th and 40K at different locations were found to be less than the world average values, while the Miami Bay values for 226Ra and 232Th were found to be greater, at 1023±47 and 2086±96Bqkg̶ 1 respectively. The main contributor to radionuclide enrichment in Miami Bay is the presence of monazite-rich black sands. The measured data were compared against literature values and also recommended limits set by the relevant international bodies. With the exception of Miami Bay, considered an elevated background radiation area that would benefit from regular monitoring, Penang island beach sands typically pose no significant radiological risk to the local populace and tourists visiting the leisure beaches.
    Matched MeSH terms: Spectrometry, Gamma
  17. A pioneering study of the radiological mapping in the world's largest mangrove forest (the Sundarbans) and implications for the public and environment
    Al Mahmud J, Siraz MMM, Alam MS, Dewan MJ, Rashid MB, Khandaker MU, et al.
    Mar Pollut Bull, 2024 May;202:116349.
    PMID: 38604081 DOI: 10.1016/j.marpolbul.2024.116349
    Coastal Mangroves are facing growing threats due to the harmful consequences of human activities. This first-ever detailed study of natural radioactivity in soil samples collected from seven tourist destinations within the Sundarbans, the world's largest mangrove forest, was conducted using HPGe gamma-ray spectrometry. Although the activity levels of 226Ra (11 ± 1-44 ± 4 Bq/kg) and 232Th (13 ± 1-68 ± 6 Bq/kg) generally align with global averages, the concentration of 40K (250 ± 20-630 ± 55 Bq/kg) was observed to surpass the worldwide average primarily due to factors like salinity intrusion, fertilizer application, agricultural runoff, which suggests the potential existence of potassium-rich mineral resources near the study sites. The assessment of the hazard parameters indicates that the majority of these parameters are within the recommended limits. The soil samples do not pose a significant radiological risk to the nearby population. The results of this study can establish important radiological baseline data before the Rooppur Nuclear Power Plant begins operating in Bangladesh.
    Matched MeSH terms: Spectrometry, Gamma
  18. Fulltext Natural radioactivity content and radionuclides lechability of bricks containing industrial waste
    Zalina Laili, Mohd Zaidi Ibrahim, Muhamat Omar
    Jurnal Sains Nuklear Malaysia, 2013;25(2):50-60.
    MyJurnal
    A study has been carried out using a gamma-ray spectrometric system to determine the natural
    radioactivity level in bricks made from industrial waste and their associated radiation hazard.
    Brick-1 and brick-2 contained waste from coal power plant and granite industry, respectively. The
    leachability of radionuclides from these bricks was also investigated. The activity concentration
    values of 226Ra,
    228Ra,
    232Th, and 40K are 64.25, 63.15, 67.9 and 254.19 Bq/kg, respectively in brick-
    1, and 193, 164.48, 164.63 and 1348.75 Bq/kg, respectively in brick-2. The radiation hazard
    indexes such as radium equivalent activities (Raeq), representative level index (Iγr), external hazard
    index (Hex) and internal hazard index (Hin) were calculated and compared with the internationally
    approved values. Results indicate that brick-1 showed less radiological hazard than brick-2. This
    suggested that brick-1 could be used in building construction without exceeding the proposed
    criterion level.The leachability of 226Ra for bricks showed the activity concentration slightly
    exceeded 1 Bq/L which is the limit generally used for industrial wastewater.
    Matched MeSH terms: Spectrometry, Gamma
  19. Fulltext A comparison technique of alpha and gamma spectrometry to measure 210Pb activity in marine sediment core
    Zal Uyun Wan Mahmood, Yii, Mei-Wo, Che Abd. Rahim Mohamed, Norfaizal Mohamed @ Mohamad, Abdul Kadir Ishak
    Jurnal Sains Nuklear Malaysia, 2013;25(2):61-67.
    MyJurnal
    The most commonly used techniques of alpha and gamma spectrometry were performed to measure
    210Pb activity in marine sediment core as a comparison. Alpha analytical technique measured the
    activity of 210Pb from it’s in-grow grand-daughter 210Po after a chemical separation, assuming
    radioactive equilibrium between the two radionuclides. Meanwhile, gamma analysis technique
    allows direct measurement, non-destructive and no preliminary chemical separation. Through the
    comparison, it is found that both alpha and gamma analysis techniques were slightly difference.
    Overall, the results from alpha analytical technique were basically higher than those from the
    gamma analytical techniques. Some logical argument had been discussed to explain this situation.
    In routine analysis, the analytical technique used should be chosen carefully based on advantages
    and disadvantages of the each technique and analysis requirements. Therefore, it is recommended to
    determine exactly the needs and purpose of analysis and to know the sample history before decide
    the appropriate analytical technique
    Matched MeSH terms: Spectrometry, Gamma
  20. Fulltext Measurement of 226ra in iaea soil-6 using gamma spectrometry system: Comparison between manual and software calculation
    Mei-Wo, Yii, Kamarozaman Ishak, Nooruzainah Abu Hassan, Maziah Mahmud, Khairul Nizam Razali
    Jurnal Sains Nuklear Malaysia, 2012;24(1):102-112.
    MyJurnal
    IAEA Soil-6 is a reference material with a certified value for 226Ra fall between 69.6 – 93.4 Bq/kg at 95% confidence level. This material has been used as a sample and performed repeat measurement weekly between years 2006 – 2009 using a same gamma spectrometry system. The activity concentration of this material is calculated automatically using the operational commercial software and compared with activity obtained from the manual calculation. Study found that only 76.9%, 64.1%, 56.3%, and 79.3% of the results from the software calculation lie within the confidence level for year 2006, 2007, 2008 and 2009, respectively. However, u-score calculation revealed that 94.9 %, 89.7%, 79.2% and 84.9% data set have no significant bias (u < 2.58) for year 2006, 2007, 2008 and 2009, respectively. On the other hand, all manual calculation data were found to be within the 95 % confidence level. Factors suspected to cause differences between these two approaches were discussed here. Manually peak search, marking and calculation still remains as the preferred option for calculating the gamma radionuclides activity unless limitations of the spectrum analysis software, as described in this paper can be resolved/improved upon.
    Matched MeSH terms: Spectrometry, Gamma
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