Displaying publications 101 - 120 of 239 in total

Abstract:
Sort:
  1. Fulltext Deliberate self-harm in a patient with hyperthyroidism with acute psychosis
    Wong HH, Pang NTP
    BMJ Case Rep, 2021 Oct 14;14(10).
    PMID: 34649855 DOI: 10.1136/bcr-2021-242333
    A woman in her 30s with underlying Graves' disease, who recently completed radioactive iodine treatment, presented with 2 weeks of acutely altered behaviour associated with auditory hallucinations and religious preoccupations. Laboratory investigation demonstrated elevated free thyroxine levels and suppressed thyroid-stimulating hormone levels. Additionally, there was a presence of antithyroid peroxidase antibodies consistent with autoimmune thyroid disease. She responded to antipsychotics and achieved biochemical euthyroidism. Subsequently, antipsychotic was tapered off during outpatient follow-up at the patient's own request, with supplement thyroxine continuing. After 1 week, acute hallucinations and religious preoccupations re-emerged, driving her to inflict self-injuries by swallowing coins and nails and banging her head against the wall, sustaining laceration wounds. Furthermore, she hammered a roofing nail into the external genitalia, embedded in the symphysis pubis. After supplemental thyroxine was stopped and olanzapine was started, she achieved biochemical euthyroid followed by remission of psychosis within 1 week. This case illustrates the importance of elucidating organic causes of psychosis as they are easily and swiftly reversible.
    Matched MeSH terms: Iodine Radioisotopes
  2. 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: Potassium Radioisotopes/analysis*; Radioisotopes/analysis
  3. The presence of natural radioactivity and 137Cs in the South China Sea bordering peninsular Malaysia
    Amin YM, Mahat RH, Nor RM, Khandaker MU, Takleef GH, Bradley DA
    Radiat Prot Dosimetry, 2013 Oct;156(4):475-80.
    PMID: 23584496 DOI: 10.1093/rpd/nct097
    The presence of natural radioactivity and (137)Cs has been investigated in fresh media obtained from South China Sea locations off the coast of peninsular Malaysia. The media include seafood, sea water and sediment. The samples were collected some weeks prior to the devastating 2011 Tōhoku earthquake and associated tsunami, the occurrence of which precipitated the Fukushima incident. All samples showed the presence of naturally occurring (226)Ra, (228)Ra and primordial (40)K, all at typically prevailing levels. The concentrations of natural radioactivity in molluscs were found to be greater than that of other marine life studied herein, the total activity ranging from 337 to 393 Bq kg(-1) dry weight. The total activity in sea water ranged from 15 to 88 Bq l(-1). Sediment samples obtained at deep sea locations more than 20 km offshore further revealed the presence of (137)Cs. The activity of (137)Cs varied from ND to 0.5 Bq kg(-1) dry weight, the activity increasing with offshore distance and depth. The activity concentrations presented herein should be considered useful in assessing the impact of any future radiological contamination to the marine environment.
    Matched MeSH terms: Cesium Radioisotopes/analysis*; Potassium Radioisotopes/analysis*
  4. Radionuclide emissions from a coal-fired power plant
    Amin YM, Khandaker MU, Shyen AK, Mahat RH, Nor RM, Bradley DA
    Appl Radiat Isot, 2013 Oct;80:109-16.
    PMID: 23891979 DOI: 10.1016/j.apradiso.2013.06.014
    Current study concerns measurement of radioactivity levels in areas surrounding a 2420 MW thermal power plant fueled predominantly by bituminous coal. The concentrations of (226)Ra, (232)Th and (40)K in onsite bottom-ash were found to be 139 Bq/kg, 108 Bq/kg and 291 Bq/kg, respectively, the levels for these radiolnuclides in soil decreasing with distance from the power plant. At the plant perimeter the respective radionuclide concentrations were 87 Bq/kg, 74 Bq/kg and 297 Bq/kg. In a nearby town, the corresponding concentrations were 104 Bq/kg, 52 Bq/kg and 358 Bq/kg, suggestive of use of TENORM affected soils. The mean radium equivalent activities (Raeq) in soil and ash sample in the town were 205 Bq/kg and 316 Bq/kg, respectively. The Kapar plant ash/slag appears to contain a higher level of TENORM than the world average. The degree of contamination is much higher inside the town where slag has been mixed with topsoil as landfill or as simple domestic waste. For the prevailing levels of exposure and a worst case senario, the predicted committed effective dose due to ingestion and inhalation for intake durations of 1- and 30 years would be 4.2 μSv and 220 μSv, respectively.
    Matched MeSH terms: Radioisotopes
  5. A strategy for bioremediation of nuclear contaminants in the environment
    Li Z, He Y, Sonne C, Lam SS, Kirkham MB, Bolan N, et al.
    Environ Pollut, 2023 Feb 15;319:120964.
    PMID: 36584860 DOI: 10.1016/j.envpol.2022.120964
    Radionuclides released from nuclear contamination harm the environment and human health. Nuclear pollution spread over large areas and the costs associated with decontamination is high. Traditional remediation methods include both chemical and physical, however, these are expensive and unsuitable for large-scale restoration. Bioremediation is the use of plants or microorganisms to remove pollutants from the environment having a lower cost and can be upscaled to eliminate contamination from soil, water and air. It is a cheap, efficient, ecologically, and friendly restoration technology. Here we review the sources of radionuclides, bioremediation methods, mechanisms of plant resistance to radionuclides and the effects on the efficiency of biological adsorption. Uptake of radionuclides by plants can be facilitated by the addition of appropriate chemical accelerators and agronomic management, such as citric acid and intercropping. Future research should accelerate the use of genetic engineering and breeding techniques to screen high-enrichment plants. In addition, field experiments should be carried out to ensure that this technology can be applied to the remediation of nuclear contaminated sites as soon as possible.
    Matched MeSH terms: Radioisotopes
  6. Assessment of radioactivity level and associated radiological hazard in fertilizer from Dhaka
    Siraz MMM, Al Mahmud J, Alam MS, Rashid MB, Hossain Z, Osman H, et al.
    Environ Monit Assess, 2024 Jan 23;196(2):192.
    PMID: 38263472 DOI: 10.1007/s10661-024-12328-4
    Miners, factory workers, traders, end-users, and foodstuff consumers all run the risk of encountering health hazards derived from the presence of elevated levels of radiation in fertilizers, as these groups often come into direct or indirect contact with fertilizers as well as raw materials throughout various linked processes such as mineral extractions, fertilizer production, agricultural practices. A total of 30 samples of various kinds of fertilizer produced in different factories in Dhaka megacity were analyzed to quantify the concentrations of primordial radionuclides using HPGe detector. Among the analyzed samples, average (range) concentration of 40K was found to be 9920 ± 1091 (8700 ± 957-11,500 ± 1265), 9100 ± 1001 (8600 ± 946-9600 ± 1056), 2565 ± 282 (2540 ± 279-2590 ± 285), and 3560 ± 392 (2620 ± 288-4500 ± 495) Bq/kg in the samples of Muriate of Potash Fertilizer, Sulphate of Potash Fertilizer, Humic Acid Fertilizer, and NPKS Fertilizer, respectively. Elevated concentration of 226Ra was found in Triple Super Phosphate Fertilizer with a mean (range) of 335 ± 37 (290 ± 32-380 ± 42) Bq/kg. The higher activity of 40K can be linked to the greater levels of elemental potassium in phosphate fertilizer. Elevated concentrations of radionuclides may also result from variations in chemical processes as well as the local geology of the mining areas where the raw materials were extracted for fertilizer production. Numerous fertilizer brands surpass prescribed limits for various hazardous parameters, presenting significant health risks to factory workers, farmers, and consumers of agricultural products. This study provides baseline information on the radioactivity of fertilizers, which could be used to develop mitigation methods, establish national fertilizer usage limits, justify regulatory frameworks, and raise public awareness of fertilizer overuse. The findings of the study could potentially help to explore the impact of fertilizer on the food chain.
    Matched MeSH terms: Radioisotopes
  7. Monte Carlo simulations and analysis of transmitted gamma ray spectra through various tissue phantoms
    Moradi F, Khandaker MU, Alrefae T, Ramazanian H, Bradley DA
    Appl Radiat Isot, 2019 Apr;146:120-126.
    PMID: 30769172 DOI: 10.1016/j.apradiso.2019.01.031
    Studies of radiation interactions with tissue equivalent material find importance in efforts that seek to avoid unjustifiable dose to patients, also in ensuring quality control of for instance nuclear medicine imaging equipment. Use of the Monte Carlo (MC) simulation tool in such characterization processes allows for the avoidance of costly experiments involving transmitted X- and γ-ray spectrometry. Present work investigates MC simulations of γ-ray transmission through tissue equivalent solid phantoms. Use has been made of a range of radionuclide gamma ray sources, 99mTc, 131I, 137Cs, 60Co (offering photons in the energy range from a few keV up to low MeV), popularly applied in medicine and in some cases for gauging in industry, obtaining the transmission spectra following their interaction with various phantom materials and thicknesses. In validation of the model, the simulated values of mass attenuation coefficients (μ/ρ) for different phantom materials and thicknesses were found to be in good agreement with reference values (NIST, 2004) to within 1.1% for all material compositions. For all of the primary photon energies and medium thicknesses of interest herein, results show that multiple scattering peaks are generally located at energies lower than 100 keV, although for the larger phantom thicknesses it is more difficult to distinguish single, double and multiple scattering in the gamma spectra. Transmitted photon spectra investigated for water, soft tissue, breast, brain and lung tissue slab phantoms are demonstrated to be practically independent of the phantom material, while a significant difference is observed for the spectra transmitted through bone that was proved to be due to the density effect and not material composition.
    Matched MeSH terms: Radioisotopes/adverse effects; Radioisotopes/therapeutic use
  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: Potassium Radioisotopes; Radioisotopes/analysis*
  9. Analytical GC-FID Method for the Determination of Organic Solvents in Radiopharmaceuticals
    Hassan H, Othman MF, Zakaria ZA, Saad FFA, Abdul Razak HR
    Curr Radiopharm, 2021;14(2):131-144.
    PMID: 33115398 DOI: 10.2174/1874471013999201027215704
    BACKGROUND: Organic solvents play an indispensable role in most of the radiopharmaceutical production stages. It is almost impossible to remove them entirely in the final formulation of the product.

    OBJECTIVE: In this presented work, an analytical method by gas chromatography coupled with flame ionization detection (GC-FID) has been developed to determine organic solvents in radiopharmaceutical samples. The effect of injection holding time, temperature variation in the injection port, and the column temperature on the analysis time and resolution (R ≥ 1.5) of ethanol and acetonitrile was studied extensively.

    METHODS: The experimental conditions were optimized with the aid of further statistical analysis; thence, the proposed method was validated following the International Council for Harmonisation (ICH) Q2 (R1) guideline.

    RESULTS: The proposed analytical method surpassed the acceptance criteria including the linearity > 0.990 (correlation coefficient of R2), precision < 2%, LOD, and LOQ, accuracy > 90% for all solvents. The separation between ethanol and acetonitrile was acceptable with a resolution R > 1.5. Further statistical analysis of Oneway ANOVA revealed that the increment in injection holding time and variation of temperature at the injection port did not significantly affect the analysis time. Nevertheless, the variation in injection port temperature substantially influenced the resolution of ethanol and acetonitrile peaks (p < 0.05).

    CONCLUSION: The proposed analytical method has been successfully implemented to determine the organic solvent in the [18F]fluoro-ethyl-tyrosine ([18F]FET), [18F]fluoromisonidazole ([18F]FMISO), and [18F]fluorothymidine ([18F]FLT).

    Matched MeSH terms: Fluorine Radioisotopes/analysis; Fluorine Radioisotopes/chemistry*
  10. Fulltext Transient hypothyroidism following I131 treatment for thyrotoxicosis
    Zaini A, Ngan A, Paramsothy M, Khoo BH, Ch'ng SL
    Med J Malaysia, 1983 Dec;38(4):331-3.
    PMID: 6599994
    Matched MeSH terms: Iodine Radioisotopes/adverse effects*; Iodine Radioisotopes/therapeutic use
  11. Release, deposition and elimination of radiocesium ((137)Cs) in the terrestrial environment
    Ashraf MA, Khan AM, Ahmad M, Akib S, Balkhair KS, Bakar NK
    Environ Geochem Health, 2014 12;36(6):1165-90.
    PMID: 24804829 DOI: 10.1007/s10653-014-9620-9
    Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is (137)Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium's high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that (137)Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of (137)Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.
    Matched MeSH terms: Cesium Radioisotopes/adverse effects; Cesium Radioisotopes/analysis
  12. Fulltext Optimization of integrated impeller mixer via radiotracer experiments
    Othman N, Kamarudin SK, Takriff MS, Rosli MI, Engku Chik EM, Adnan MA
    ScientificWorldJournal, 2014;2014:242658.
    PMID: 24741344 DOI: 10.1155/2014/242658
    Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, V dead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and V dead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization.
    Matched MeSH terms: Radioisotopes/analysis*; Radioisotopes/chemistry*
  13. Fulltext Therapeutic radionuclides in nuclear medicine: current and future prospects
    Yeong CH, Cheng MH, Ng KH
    J Zhejiang Univ Sci B, 2014 Oct;15(10):845-63.
    PMID: 25294374 DOI: 10.1631/jzus.B1400131
    The potential use of radionuclides in therapy has been recognized for many decades. A number of radionuclides, such as iodine-131 ((131)I), phosphorous-32 ((32)P), strontium-90 ((90)Sr), and yttrium-90 ((90)Y), have been used successfully for the treatment of many benign and malignant disorders. Recently, the rapid growth of this branch of nuclear medicine has been stimulated by the introduction of a number of new radionuclides and radiopharmaceuticals for the treatment of metastatic bone pain and neuroendocrine and other malignant or non-malignant tumours. Today, the field of radionuclide therapy is enjoying an exciting phase and is poised for greater growth and development in the coming years. For example, in Asia, the high prevalence of thyroid and liver diseases has prompted many novel developments and clinical trials using targeted radionuclide therapy. This paper reviews the characteristics and clinical applications of the commonly available therapeutic radionuclides, as well as the problems and issues involved in translating novel radionuclides into clinical therapies.
    Matched MeSH terms: Radioisotopes/therapeutic use*; Radioisotopes/chemistry*
  14. Fulltext Preparation, Characterization, and Radiolabeling of [68Ga]Ga-NODAGA-Pamidronic Acid: A Potential PET Bone Imaging Agent
    Ashhar Z, Yusof NA, Ahmad Saad FF, Mohd Nor SM, Mohammad F, Bahrin Wan Kamal WH, et al.
    Molecules, 2020 Jun 09;25(11).
    PMID: 32526838 DOI: 10.3390/molecules25112668
    Early diagnosis of bone metastases is crucial to prevent skeletal-related events, and for that, the non-invasive techniques to diagnose bone metastases that make use of image-guided radiopharmaceuticals are being employed as an alternative to traditional biopsies. Hence, in the present work, we tested the efficacy of a gallium-68 (68Ga)-based compound as a radiopharmaceutical agent towards the bone imaging in positron emitting tomography (PET). For that, we prepared, thoroughly characterized, and radiolabeled [68Ga]Ga-NODAGA-pamidronic acid radiopharmaceutical, a 68Ga precursor for PET bone cancer imaging applications. The preparation of NODAGA-pamidronic acid was performed via the N-Hydroxysuccinimide (NHS) ester strategy and was characterized using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MSn). The unreacted NODAGA chelator was separated using the ion-suppression reverse phase-high performance liquid chromatography (RP-HPLC) method, and the freeze-dried NODAGA-pamidronic acid was radiolabeled with 68Ga. The radiolabeling condition was found to be most optimum at a pH ranging from 4 to 4.5 and a temperature of above 60 °C. From previous work, we found that the pamidronic acid itself has a good bone binding affinity. Moreover, from the analysis of the results, the ionic structure of radiolabeled [68Ga]Ga-NODAGA-pamidronic acid has the ability to improve the blood clearance and may exert good renal excretion, enhance the bone-to-background ratio, and consequently the final image quality. This was reflected by both the in vitro bone binding assay and in vivo animal biodistribution presented in this research.
    Matched MeSH terms: Gallium Radioisotopes/pharmacokinetics*; Gallium Radioisotopes/chemistry
  15. Thyroid eye disease--medical or surgical therapy?
    Khalid BA, Ng ML
    Ann Acad Med Singap, 1991 Mar;20(2):273-6.
    PMID: 1883189
    Thyroid eye disease is autoimmune in nature and associated with Graves' Disease. Autoantibodies to the 64 kDa antigen in thyroid membranes cross-react to the 64 kDa proteins in human eye muscle membranes. Antibody dependent cell mediated cytotoxicity against eye muscle cells are also found in patients with thyroid eye disease. The purpose of this paper is to review the treatment available and to share the authors' experience using cyclosporin A. In the majority of cases, thyroid eye disease is mild, manifest only as bilateral or unilateral proptosis, with/without grittiness of the eyes. This is usually treated conservatively with eye drops. If proptosis is more severe and there is incomplete closure of eyelids, epiphora and conjunctival injection, then lateral tarrsorrhaphy is usually effective, combined with use of eye pads and eye drops. The problem of diplopia can be treated conservatively with special lenses, or with surgical correction of tethered muscles. However when proptosis is severe, with raised intraocular pressure, severe chemosis and danger of blindness, then the choice of therapy is controversial: rapid decompression by surgical means or use of high doses of prednisolone. Most prefer prednisolone therapy initially, surgical decompression if it fails. Various other methods have been tried, aimed at the immunological nature of the disease, namely plasmapheresis, radiotherapy and immunosuppressive drugs such as cyclosporin, with variable success. Our experience with cyclosporin had been mixed and inconclusive.
    Matched MeSH terms: Iodine Radioisotopes/administration & dosage; Iodine Radioisotopes/therapeutic use
  16. Fulltext 10Po, 210Pb and 210Po/210Pb in sediment core from surrounding Sungai Linggi estuary
    Zal U’yun Wan Mahmood, Mei, Wo Yii, Abdul Kadir Ishak
    Jurnal Sains Nuklear Malaysia, 2016;28(1):1-8.
    MyJurnal
    This study was performed to observe the variation in the distribution of 210Po,210Pb and 210Po/210Pb activity ratio throughtheir vertical profile of the sediment cores takenat surrounding Sungai Linggi estuary. Five sediment cores were takenin February 2011 and were cutto an intervalof 2 cm layer. Activity concentrations of 210Po and 210Pb were determined using alpha radiochemical analysis and gamma direct measurement, respectively. Generally, the measured activity of 210Po, 210Pb and 210Po/210Pbwere in the ranges of 22.73 –139.06 Bqkg-1dw., 37.88 –176.24 Bqkg-1dw.and 0.23 –1.34, respectively. The variation in the distribution profile for the radionuclides are believed to be influencedby human activities such as agriculture, fertilizer, vehicles, burned fuel fossil and forest, industrialand others via river input from land-base.Other factor is due to organic mattercontent played importantrole as the geochemical carrier to transportthose radionuclides at study area. It was provedthat hasa strong correlation between the radionuclide distribution and the sedimentcomposition of organic matter.Furthermore, in those rangesreflectedthat 210Pb activities were higher than210Po with an activity ratio average of 0.79. This is probably due to dramatic increase of excess 210Pb supplied from atmospheric deposition, in situ decay of 226Ra and as a result of diagenetic remolibilazationof 210Pbin deeper layesof the sediment column. Thus, thosefactors are majorcontributions on thevariation of 210Po and 210Pb in the sediment core at surrounding Sungai Linggi estuary.
    Matched MeSH terms: Lead Radioisotopes
  17. Fulltext The minimum amount of fluids needed to achieve the fastest time to reach permissible level for release in well-differentiated thyroid patients undergoing high-dose I-131 therapy
    Cheen Hoe AK, Fong LY, Halim FNA, Fatt QK, Hamzah F
    World J Nucl Med, 2018 7 24;17(3):182-187.
    PMID: 30034283 DOI: 10.4103/wjnm.WJNM_59_17
    Radioiodine (131I) therapy is the mainstay of treatment for patients who had undergone total thyroidectomy for well differentiated thyroid carcinoma. Increased fluid intake has always been encouraged to minimize the risk of non-target organ exposure to I-131radiation. This study aimed to determine the minimum amount of fluids needed for patients to have the fastest time to achieve permissible level for release after high dose I-131therapy.

    METHODOLOGY: All the patients who were treated with high dose I-131from 18th January 2016 till 31st December 2016 in Hospital Pulau Pinang, Malaysia were recruited. The data from 126 patients on thyroxine hormone withdrawal (THW) group and 18 patients on recombinant human thyroid stimulating hormone (rhTSH) group were analysed. There is no change in patient management in terms of preparation, dose or post therapy whole-body scan. Fluid intake of patients were monitored strictly and whole-body retention of I-131are measured using ionizing chamber meter immediately after ingestion of I-131then at 1 hour, 24 hours, 48 hours, 72 hours and 96 hours.

    RESULTS: The median time to achieve permissible release limit (50 μSV/hr at 1 meter) was 21.6 hours and 22.1 hours post-ingestion of I-131in the THW and rhTSH group respectively. The minimum amount of fluid needed to reach permissible release limit in the fastest time was 2,103 ml and 2,148ml for the THW and TSH respectively.

    CONCLUSION: Clinicians would be able to evidently advise their patient on the amount of fluid to consume and utilize their isolation wards faster to treat more patients.

    Matched MeSH terms: Iodine Radioisotopes
  18. Fulltext Assessment of the genetic variability and fibre composition of Gamma Ray induced mutant lines of Ginger (Zingiber Officinale Roscoe)
    Nor Yusliza Kamaruddin, Shamsiah Abdullah
    Pertanika Journal of Science & Technology, 2017;25(103):325-334.
    MyJurnal
    This study looked at mutagenic effectiveness of gamma rays d on two varieties of Zingiber officinale Roscoe: Bentong and Tanjung Sepat. The rhizomes were exposed to different doses (0, 5, 7, 9, 11, 13 and 15 Gy) using Caesium-137 as source of the gamma rays. The effect of different gamma doses on the crude fibre composition of irradiated ginger was studied and genetic variability was assessed using molecular marker technique, RAPD. Findings showed different doses of gamma rays could induce variability in these two ginger varieties and the effect was found to be variety-dependent. Bentong variety irradiated with 9 Gy recorded 8.53% of crude fibre composition while Tanjung Sepat irradiated ginger with 5 Gy recorded 8.70% of crude fibre which gave the lowest composition compared with other irradiated ginger. A total of nine different arbitrary decamers were used as primers to amplify DNA from mutant plant material to assess their polymorphism level of ginger mutant lines. Polymorphism of all mutant lines was 97.62% indicating that there were significant changes in genetic sequences in irradiated ginger genotypes.
    Matched MeSH terms: Cesium Radioisotopes
  19. Use of a modified natural-rubber phantom for radiotherapy dosimetry measurements
    Bradley DA, Ng KH, Aziz YB
    Int J Rad Appl Instrum A, 1988;39(5):439-40.
    PMID: 2840420
    The utility of a phantom material, based on SMR(L) [Standard Malaysian Rubber] grade natural rubber and a formulation used for the proprietary rubber phantom-material, Temex, has been examined for the 1-MeV photon-Measurement has also been performed with 60-keV photons using the radionuclide 241Am. At photon-therapy energy levels the measured response, when compared with tabulated central-axis percentage depth doses for the defined measuring conditions, produces everywhere (in the range 1-19 cm depth) better than 2% deviation. The favourable measured response characteristics combined with the ease of processing and casting the phantom material provide the basis for useful radiotherapy machine calibration and anthropomorphic dosimetry measurements. The measured mass-attenuation coefficient, at 60keV, of 0.204 cm2 g-1 (+/- 3%) is in close agreement with tabulated values for water (0.2055 cm2 g-1).
    Matched MeSH terms: Cobalt Radioisotopes
  20. Natural dead sea salt and retrospective dosimetry
    Wahib NB, Abdul Sani SF, Ramli A, Ismail SS, Abdul Jabar MH, Khandaker MU, et al.
    Radiat Environ Biophys, 2020 08;59(3):523-537.
    PMID: 32462382 DOI: 10.1007/s00411-020-00846-x
    Accidents resulting in widespread dispersal of radioactive materials have given rise to a need for materials that are convenient in allowing individual dose assessment. The present study examines natural Dead Sea salt adopted as a model thermoluminescence dosimetry system. Samples were prepared in two different forms, loose-raw and loose-ground, subsequently exposed to 60Co gamma-rays, delivering doses in the range 2-10 Gy. Key thermoluminescence (TL) properties were examined, including glow curves, dose response, sensitivity, reproducibility and fading. Glow curves shapes were found to be independent of given dose, prominent TL peaks for the raw and ground samples appearing in the temperature ranges 361-385 ºC and 366-401 ºC, respectively. The deconvolution of glow curves has been undertaken using GlowFit, resulting in ten overlapping first-order kinetic glow peaks. For both sample forms, the integrated TL yield displays linearity of response with dose, the loose-raw salt showing some 2.5 × the sensitivity of the ground salt. The samples showed similar degrees of fading, with respective residual signals 28 days post-irradiation of 66% and 62% for the ground and raw forms respectively; conversely, confronted by light-induced fading the respective signal losses were 62% and 80%. The effective atomic number of the Dead Sea salt of 16.3 is comparable to that of TLD-200 (Zeff 16.3), suitable as an environmental radiation monitor in accident situations but requiring careful calibration in the reconstruction of soft tissue dose (soft tissue Zeff 7.2). Sample luminescence studies were carried out via Raman and Photoluminescence spectroscopy as well as X-ray diffraction, ionizing radiation dependent variation in lattice structure being found to influence TL response.
    Matched MeSH terms: Cobalt Radioisotopes
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links