Pakistan Institute of Nuclear Science and Technology

Islamabad, Pakistan

Pakistan Institute of Nuclear Science and Technology

Islamabad, Pakistan
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Rana M.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

Defect structure of latent tracks and their chemical etching are basic issues in solid state nuclear track detection and their advanced understanding helps to extend their applications in different disciplines of science and technology. These fundamental issues are analyzed here using computational and experimental investigations proposing physically appreciable models. A brief description of possible future directions for further extension of nuclear track detection technique is also given. Results, discussion and analysis given here present a comprehensive picture of essential aspects of nuclear track detection. © 2009 Elsevier B.V. All rights reserved.


Rana M.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

Systematically planned new experiments were performed on fission fragment and alpha particle tracks in CR-39. In the present experiments, special attention was paid to reduction of spurious variations and fluctuations during exposures, chemical etching and etched track measurements. Measurements of etch induction time (tei) for fission fragment and alpha particle (of energy 4.59-6.11 MeV) tracks were carried out. Potential of tei for alpha particle spectrometry with CR-39 detector is demonstrated. Published results of atomic force microscopy (AFM) and conductometric cell measurements of various charged particle tracks in CR-39 and similar polymers were used as a support of the present results to propose a multiplex mechanism of startup of chemical etching of charged particle tracks. Results are useful for further development in the field of nuclear tracks and technology applications including nanotechnology. © 2010 Elsevier B.V.


Abbasi I.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Medicine and Biology | Year: 2012

Objective: 99mTc-Sn-PYP (Technetium-99m labeled tin pyrophosphate) has been widely used as a radiopharmaceutical for bone scanning as well as in nuclear cardiology. It is also found in the body in trace amounts. 177Lu is presently considered as an excellent radionuclide for developing bone pain palliation agents. PYP is an analogue of MDP and MDP has been labeled with 177Lu. No study on preparing a complex of 177Lu with PYP has been reported yet. Based on these facts, it was hypothesized that a bone-seeking 177Lu-PYP (Lutetium-177 labeled Pyrophosphate) radiopharmaceutical could be developed as an agent for palliative radiotherapy of bone pain due to skeletal metastases. Methods: 177Lu was produced by irradiating lutetium foil (11mg) natural target at a flux ~1.0×1014n/cm2/s for 12h in the swimming pool type reactor. 177Lu in the form of 177LuCl3 was labeled with PYP. The radiochemical purity and labeling efficiencies were determined by paper chromatography. Labeling of 177Lu with PYP was optimized and a labeled sample was subjected to HPLC analysis. To determine the charge on the 177Lu-PYP complex, radio-electrophoresis was conducted for 1 h under a voltage of 300V and 45mA current using 0.025M phosphate buffer (pH 6.9). Bioevaluation studies with rabbit under γ-camera were also performed to verify the skeletal uptake. Results: The quality control using paper radio-chromatography has shown >99% radiochemical purity of 177Lu-PYP complex. Radio-chromatography also showed maximum labeling at ligand/metal ratio=60:1. HPLC analysis showed 1.42±0.01min retention time of 177Lu-PYP complex. No decrease in labeling was observed at higher temperatures. Gamma-camera images of 177Lu-PYP in normal rabbit at 24h post injection also showed high skeletal uptake. Conclusion: The study demonstrated that sodium pyrophosphate could be labeled with 177Lu with high radiochemical yields (>99%). Negatively charged 177Lu-PYP complex retained stability for a day and at high temperatures too. Gamma-camera images of 177Lu-PYP in normal rabbit at 24h post injection showed high skeletal uptake, suggesting that it may be useful as a bone-pain palliation agent for the treatment of bone metastases. © 2012 Elsevier Inc.


Abbasi I.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Medicine and Biology | Year: 2011

Objective: 99mTc-MDP (technetium-99m-labeled methylene diphosphonate) has been widely used as a radiopharmaceutical for bone scintigraphy in cases of metastatic bone disease. 177Lu is presently considered as an excellent radionuclide for developing bone pain palliation agents. No study on preparing a complex of 177Lu with MDP has been reported yet. Based on these facts, it was hypothesized that a bone-seeking 177Lu-MDP (lutetium-177-labeled MDP) radiopharmaceutical could be developed as an agent for palliative radiotherapy of bone pain due to skeletal metastases. Biodistribution studies after intravenous injection of 177Lu-MDP complex in rats may yield important information to assess its potential for clinical use as a bone pain palliation agent for the treatment of bone metastases. Methods: 177Lu was produced by irradiating natural Lu2O3 (10 mg) target at a thermal flux ~8.0×1013 n/cm2 per second for 12 h in the swimming pool-type reactor.177Lu was labeled with MDP by adding nearly 37 MBq (1.0 mCi) of 177LuCl3 to a vial containing 10 mg MDP. The radiochemical purity and labeling efficiencies were determined by thin layer chromatography. Labeling of 177Lu with MDP was optimized, and one sample was subjected to high-performance liquid chromatography (HPLC) analysis. Twelve Sprague-Dawley rats were injected with 18.5 MBq (0.5 mCi). 177Lu-MDP in a volume of 0.1 ml was injected intravenously and then sacrificed at 2 min, 1 h, 2 h and 22 h (three rats at each time point) after injection. Samples of various organs were separated, weighed and measured for radioactivity and expressed as percent uptake of injected dose per gram. Bioevaluation studies with rats under gamma-camera were also performed to verify the results. Results: The quality control using thin layer chromatography has shown >99% radiochemical purity of 177Lu-MDP complex. Chromatography with Whatman 3MM paper showed maximum labeling at pH=6, incubation time=30 min, and ligand/metal ratio=60:1. HPLC analysis showed 1.35±0.05 min retention time of 177Lu-MDP complex. No decrease in labeling was observed at higher temperatures, and the stability of the complex was found adequate. Biodistribution studies of 177Lu-MDP revealed high skeletal uptake, i.e., 31.29±1.27% of the injected dose at 22 h post injection. Gamma-camera images of 177Lu-MDP in Sprague-Dawley rats also showed high skeletal uptake and verified the results. Conclusion: The study demonstrated that MDP could be labeled with 177Lu with high radiochemical yields (>99%). The in vitro stability of the complex was found adequate. Biodistribution studies in Sprague-Dawley rats indicated selective bone accumulation, relatively low uptake in soft tissue (except liver) and higher skeletal uptake, suggesting that it may be useful as a bone pain palliation agent for the treatment of bone metastases. © 2011 Elsevier Inc.


Matiullah M.,Pakistan Institute of Nuclear Science and Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013

CR-39 based radon detectors are widely used in measuring indoor radon. In this regard, different groups have developed their own systems. However, before using any system for indoor radon measurements, it has, first, to be calibrated with a known source of radon. In the current study, CR-39 based NRPB type radon detector has been calibrated and presented. In this regard, about 200 holders for CR-39 were obtained from the Radiation Protection Division of the Health Protection Agency (former NRPB), UK and several thousand more similar detector holders, hereafter called NRPB type holders, were fabricated locally in Pakistan. Uranium ore samples of known grade were placed into the plastic containers of volume 5.4 × 103 cm3 and CR-39 detectors were placed in the NRPB type holders and were then installed into the containers at a distance of 25 cm from the surface of the known grade ore samples. The containers were hermetically sealed and the detectors were allowed to expose to radon for 3 weeks. After 16 h etching in 25 % NaOH at 80 C, the measured track densities were related to the radon concentration. The calibration factor of 2.563 tracks cm-2 h-1/kBq m -3 was obtained. © 2013 Akadémiai Kiadó, Budapest, Hungary.


Mushtaq A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Engineering and Design | Year: 2011

In all probability, the same criteria applied to evaluate the safety of the reactor fuel shall be used to evaluate the safety of the targets used for the production of fission molybdenum-99. Thus, neutronic and thermal hydraulics considerations will dictate the maximum power of the targets, their uranium content, and the uniformity requirements for their loading. Radiography technique is capable of characterizing both meat location and density. Specifically, target plates that meet fuel density specifications can be irradiated with little risk of power peaking and hot spots. An adequate characterization and qualification of target plate cladding is also critical, because cladding breaches will contaminate the reactor coolant. Bend testing is a dependable way of testing bond strength while Ultrasonic Testing (UT) examinations qualify both bonding homogeneity and minimum thickness of that cladding. The bonding quality is inspected by means of a blister test. Lastly, optical microscopy is applied for clad thickness, which further supports the veracity of the UT characterization method. Natural U/Al alloy plate targets have been safely irradiated in the core of Pakistan Research Reactor-1. © 2010 Elsevier B.V. All rights reserved.


Mushtaq A.,Pakistan Institute of Nuclear Science and Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2012

The demand of radioisotopes is rising due to wide-ranging applications in industry, agriculture, medicine and in research. Two sources of artificial radioisotopes are accelerators and reactors. The reactor offers large volume for irradiation, simultaneous irradiation of different samples and economy of production, whereas accelerators are generally used to produce those isotopes which can not be produced by reactor. Radioisotope production started on a significant scale in several countries with the commissioning of research reactors starting from the late 1950s. The period from 1950 to 1970 saw construction of a large number of research reactors with multiple facilities. After 1980, because of the decommissioning of many old ones, the number of operating reactors has been steadily decreasing. The research reactors used for radioisotope production could be broadly classified into swimming pool type and tank type reactors. CANDU power reactors currently produce many millions of curies per year of 60Co for MDS Nordion's use in industry and commerce. Studies related to production of other isotopes in power reactors have also been performed. Indeed, while a very few reactors have come online in the past decade, many more have been retired or may retire in coming years. After failure of MAPLE project, there has been unwillingness to built new reactors. Activism and politics has made it so difficult to build new reactors that we are left to use only the reactors we inherited from a nuclear era. Many design considerations and requirements for the production of isotopes in power reactors must be assessed, such as; operator and public safety, minimum impact on station efficiency and reactor operations, shielding requirements during reactor operation with target adjusters and removal of the target adjusters from core, transportation within the station, and finally the processing and shipment off-site. Use of power reactors for isotope production is reviewed. © 2012 Akadémiai Kiadó, Budapest, Hungary.


Matiullah,Pakistan Institute of Nuclear Science and Technology
Journal of radiological protection : official journal of the Society for Radiological Protection | Year: 2012

Indoor radon and its decay products are considered to be the second leading cause of lung cancer after cigarette smoking. This is why extensive radon surveys have been carried out in many countries of the world, including Pakistan. In this context, 25 spots were selected at workplaces in the vicinity of the uranium mining site in Dera Ghazi Khan District for indoor radon measurement. For this purpose, CR-39 based radon detectors were installed at head height and were exposed to indoor radon for 60 days. After retrieval, these detectors were etched in a 6 M solution of NaOH at the temperature of 80 °C for 16 h in order to make the alpha particle tracks visible. The observed track densities were related to the indoor radon concentration using a calibration factor of 2.7 tracks cm(-2) h(-1)/kBq m(-3). The measured indoor radon concentration ranged from ∼386 ±161 to 3028 ± 57 Bq m(-3) with an average value of 1508 ± 81 Bq m(-3) in the studied areas of Dera Ghazi Khan District. The mean annual effective dose ranged from 2.22 ± 0.93 to 17.44 ± 0.33 mSv yr(-1), with an average of 8.68 ± 0.47 mSv yr(-1). The effect of the seasonal correction factor (SCF) on the annual average radon concentration has also been considered. Results of the current study show that, for the majority of the workplaces studied, indoor radon levels exceed the action levels proposed by many world organisations.


Wasim M.,Pakistan Institute of Nuclear Science and Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

The GammaLab is a collection of computer codes, written in MATLAB, for performing calculations involved in k 0 neutron activation analysis. The main features of the program include calibrations including energy-channel, energy-FWHM and energy-efficiency for different geometries, background subtraction, nuclide identification, spectral interference correction, elemental concentration and limit of detection determination. The data input is taken from two files one is the spectrum file stored in IAEA ASCII format and other is report file containing peak energy and peak area data. The information about sample, irradiation and counting conditions, background spectra are retrieved from QAQCData database. GammaLab takes nuclear data such as gamma lines, emission probabilities, half-lives, and k 0 factors from NucData database. The sample results which contain elemental concentrations with uncertainties are stored in the QAQCData database. The program has been evaluated by analyzing several hundred spectra and results were found satisfactory. © 2010 Akadémiai Kiadó, Budapest, Hungary.


Rana M.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2012

Mechanisms and kinetics of etching and annealing of fission fragment tracks in CR-39 have been investigated. Kinetics of bulk etching and that of fission fragment track etching in CR-39 are described in a systematic manner. Activation energies of etching and annealing were determined from the experimental results through Arrhenius type, t=t oexp(E a/k BT), empirical relationships and models. The increase of free energy in fission fragment track formation in CR-39 is also determined from the measurements of track parameters. Activation barriers of bulk etching, track etching and track annealing in CR-39 are compared and discussed. This paper presents an anatomy of fission fragment tracks. Analyses of experimental results and comparison of above mentioned energies have yielded the important physics information usable in nuclear track methodologies, including nuclear geophysics and geochemistry, and radiation damage in solids. © 2012 Elsevier B.V. All rights reserved.

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