We report a computational investigation of electron scattering by anthracene (C(14)H(10)) in the gas phase. Integral and differential cross sections have been calculated by employing two distinct ab-initio quantum scattering methods: the symmetry adapted-single centre expansion method (ePOLYSCAT) and a screening corrected form of the independent atom model (IAM-SCAR) at low and high energies, respectively. After a detailed evaluation of the current results, we present a complete set of integral scattering cross sections from 0.00001 to 10,000eV.
In this study, the stopping power for electrons in toluene is reported for incident energies ranging from 10 to 10,000 eV. The present results have been obtained by combining the calculated inelastic electron scattering cross-sections with an experimental energy loss procedure. Calculations have been carried out by means of a quasifree absorption model whose reliability has been checked by comparison with empirical electron scattering total cross section data. Results have been compared with the high-energy stopping power data available in the literature. For energies below 1 keV these are the first results of the stopping power for electrons in toluene.
The thermal neutron-induced activation cross section for the (186)W(n,gamma)(187)W reaction was measured at 0.0536eV neutron energy using TRIGA Mark-II research reactor, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh. The (197)Au(n,gamma)(198)Au monitor reaction induced in a high-purity gold foil was used to determine the effective neutron beam intensity. The activities induced in sample and monitor foils were measured nondestructively by a high-resolution HPGe gamma-ray detector. The present experimental cross-section value is the first one at 0.0536eV. The obtained new cross section that amounts to 26.6+/-1.6b is 2% higher than the recently reported data in ENDF/B-VII and 5% lower than that of JENDL-3.3.
Because of angular-momentum conservation, superallowed β decay between 0(+) analog states involves only the vector part of the weak interaction, so its measured ft value can be used to determine the vector coupling constant, GV. If many such transitions are measured, then the constancy of GV can be established and several important tests made on fundamentals of the electroweak Standard Model. We have developed apparatus that allows us to measure half-lives to ±0.03% and branching ratios to ±0.1% or better, for cyclotron-produced activities with half-lives as short as 100ms. We present an overview of the equipment and a summary of more than 10 years of results.
The cross-sections of (nat)Yb (n,x)(172,173) Tm, (174)Yb(n,p) (174) Tm, (174)Yb (n,α) (171)Er, (176)Yb(n,p) (176) Tm, (176)Yb(n,α)(173) Er, and (176) Yb(n,n')(176m)Yb have been measured at 14.6±0.3MeV neutron energy, among them two cross-sections (nat)Yb (n,x)(172,173)Tm are reported for the first time. These experimental cross-sections are compared with experimental data found in the literature, with evaluated nuclear data in JENDL-4.0 and TENDL-2010 libraries and with theoretically calculated values based on nuclear reaction modular codes EMPIRE-3.0 and TALYS-1.2.
The mass energy absorption, the mass energy transfer and mass absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass energy transfer and mass absorption coefficients for gamma rays with an incident energy range between 0.4 and 10 MeV in nitrogen, silicon, carbon, copper and sodium iodide. The mass absorption and mass energy transfer coefficients for gamma rays were calculated, and the results obtained were compared with the values reported in the literature.
Cross sections of 141Pr(n,gamma) 142Pr reaction are measured at neutron energies of 0.54, 1.09 and 1.59 MeV using the activation method. The activities of the products are counted with a high resolution HPGe detector gamma-ray spectrometer. The neutron fluence is determined by 197Au(n,gamma)198 Au reaction cross sections. The errors of the measured results are +/-6-7%. The neutron capture cross sections for this reaction are also calculated with the NUNF code. Our results are compared with those of other authors. Recommendations for inclusion of data in the energy region 0.05-3.90 MeV are made, these being in good agreement with the ENDF/B-VI data.
Thermoluminescence and optically stimulated luminescence properties of phosphate glasses doped with BaO and Li(2)O at various concentrations were studied. Lithium-doped glasses show a broad TL peak in the 200-300°C region with poor dosimetric characteristics. Barium-doped glasses feature at least two TL peaks, approximately at 200 and 400°C, which were attributed to Ba(2+) ions. They also produce a fast-decaying OSL signal correlated with the lower-temperature TL peak. Responses of both TL emissions to radiation doses up to 100 Gy are linear (R² >0.99). Due to its encouraging characteristics such as acceptable batch homogeneity, good measurement reproducibility and weak signal fading, the P₂O₅-xBaO glass can be considered as a candidate material for dosimetry in the high-dose range (>10 Gy).
The simultaneous effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma photons was studied experimentally. An intense collimated beam, obtained from 6-Ci (137)Cs source, is allowed to impinge on cylindrical aluminium samples of varying diameter and the scattered photons are detected by a 51 mm x 51 mm NaI(Tl) scintillation detector placed at 90 degrees to the incident beam. The full energy peak corresponding to singly scattered events is reconstructed analytically. The thickness at which the multiply scattered events saturate is determined for different detector collimators. The parameters like signal-to-noise ratio and multiply scatter fraction (MSF) have also been deduced and support the work carried out by Shengli et al. [2000. EGS4 simulation of Compton scattering for nondestructive testing. KEK proceedings 200-20, Tsukuba, Japan, pp. 216-223] and Barnea et al. [1995. A study of multiple scattering background in Compton scatter imaging. NDT & E International 28, 155-162] based upon Monte Carlo calculations.
A new calculation of the stopping powers (SP) and inelastic mean free paths (IMFP) for electrons in toluene at energies below 10 keV has been presented. The calculation is based on the dielectric model and on an empirical evaluation approach of optical energy loss function (OELF). The reliability for the evaluated OELFs of several hydrocarbons with available experimental optical data has been systematically checked. For toluene, using the empirical OELF, the evaluated mean ionization potential, is compared with that given by Bragg's rule, and the calculated SP at 10 keV is also compared with the Bethe-Bloch prediction. The present results for SP and IMFP provide an alternative basic data for the study on the energy deposition of low-energy electrons transport through toluene, and also show that the method used in this work may be a good one for evaluating the SP and IMFP for hydrocarbons.
The preparation of no-carrier-added 18F labelled NNC 12-0817 (1-(2-[bis(4-fluorophenyl)methoxy]ethyl)-4-[4-oxo-4-(2- thienyl)butyl]piperazine) and NNC 12-0818 (1-(2[bis(4- fluorophenyl)methoxy]ethyl)-4-]4-hydroxy-4-(2-thienyl)butyl]piperazine) is described. NNC 12-0818 is the designation of the racemic mixture of two enantiomers. Fluorine-18 is introduced into 4-[18F]fluoro-4'-fluorobenzophenone from the corresponding triflate salt by a nucleophilic aromatic substitution reaction. A no-carrier-added synthesis was performed in 6 steps starting from N,N-dimethylaniline and 4-fluorobenzoyl chloride giving [18F]NNC 12-0817 and [18F]NNC 12-0818 in good yields and a radiochemical purity after HPLC-purification higher than 99%.
2-(1,1-dicyanopropen-2-yl)-6-(2-[18F]-fluoroethyl)-methylamino-naphthalene ([18F]FDDNP) was synthesized in a single step labeling procedure. The precursor, 2-(1,1-dicyanopropen-2-yl)-6-(2-tosyloxyoethyl)-methylamino-naphthalene, was fluorinated with 18F in acetonitrile. After 15 min the reaction mixture was subjected to preparative HPLC purification. The product was isolated from the HPLC eluent with solid-phase extraction, and formulated in an ascorbic acid solution to prevent formation of side products during formulation. Quantitative sticking to tubing and filters was overcome by the addition of polysorbatum-80. This formulation yielded an isotonic, pyrogen-free and sterile solution of [18F]FDDNP. The overall decay-corrected radiochemical yield was 41+/-11% (n=22). Radiochemical purity was >98% and the specific activity was 102+/-56 GBq/micromol at the end of synthesis.
1,2-Palmitoyl-3-[15-(4-iodophenyl)pentadecan-3-oyl]-rac-glycerol (MIPAG) is a new agent for the clinical evaluation of pancreatic lipase activity and has demonstrated promise in preliminary clinical studies with patients affected with pancreatic insufficiency. Iodine-131-MIPAG was initially prepared via thallium-iodide displacement. Because of the need for a simple method which is amendable for the routine clinical use of MIPAG we have investigated the preparation and radioiodination of MIPAG utilizing the tributyltin precursor, 1,2-palmitoyl-3-[15-(4-tributylstannylphenyl)pentadecan-3-oy l]-rac-glycerol (TBT-MIPAG, 2). Compound 2 was prepared via the condensation of 1,2-palmitoyl-rac-glycerol with 15-(4-tributylstannylphenyl)pentadecanoic acid (TBT-PPA) prepared from 4-bromophenylacetylene. Electrophilic radioiodination using peracetic acid with sodium iodide-125 in ethanol at 80 degrees C for 60 min afforded I-125-MIPAG in 65.9% (+/- 11.5%) yield and radiochemical purity of 94% (+/- 3.0%) after C-18 Sep-Pak purification (n = 6). This improved method for radioiodination utilizing TBT-MIPAG now provides radioiodinated MIPAG for routine clinical evaluation.
Selenium-75 (t1/2 = 120.4d; 100% EC) was prepared in no-carrier-added form by 22MeV proton-bombardment of natural arsenic(III) oxide powder held in a copper-aluminum drawer target (highest yield, 35 microCi/microAh; maximum current, 6 microA), followed by oxidation to [75Se]selenium(IV) oxide. No-carrier-added [75Se]5-ethoxycarbonyl-4-methyl-1,2,3-selenadiazole was prepared in one step from ethylacetoacetate semicarbazone with [75Se]selenium(IV) oxide in glacial acetic acid at 50 degrees C. Column chromatography of the final solution afforded the desired labeled compound in 30% yield and greater than 98% radiochemical purity.
Two 1,2,3-triazole anticonvulsants, 1-(4-methylsulfone-phenyl)-5-(4-methyl-phenyl)-1,2,3-triazole and 1-(4-methylsulfone-phenyl)-5-phenyl-1,2,3-triazole, both labeled with carbon-14 in the 5-position were prepared from para-tolunitrile-[cyano-14C] and benzonitrile-[cyano-14C], respectively.
Small conductance Ca2+-activated K+ (SKCa) channels play an important role in many functions such as neuronal communication and behavioral plasticity, secretion, and cell proliferation. SKCa channel modulation is associated with various brain, heart, and cancer diseases. N-methyl-laudanosine and its structurally related derivatives, substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums, are reversible and selective SKCa channel blockers. Carbon-11 labeled N-methyl-laudanosine and its tetrahydroisoquinolinium derivatives may serve as new probes for positron emission tomography (PET) to image SKCa channels in the brain, heart, and cancer. The key intermediates, substituted isoquinolines (3a-c), were synthesized using a modification of the Pomeranz-Fritsch procedure. The precursors, substituted 1-(3,4-dimethoxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinolines (8a-c), and their corresponding reference standards, substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums (9a-c), were synthesized from compounds 3a-c with 3,4-dimethoxybenzyl chloride (2) in multiple steps with moderate to excellent chemical yields. The precursor 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinoline (10) was commercially available, and the methylation of compound 10 with methyl iodide provided N-methyl-laudanosine (11). The target quaternary ammonium tracers, carbon-11 labeled 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums ([11C]9a-c and [11C]11), were prepared by N-[11C]methylation of the tertiary amine precursors (8a-c and 10) with [11C]methyl triflate and isolated by a simplified solid-phase extraction (SPE) purification using a SiO2 or cation-exchange CM Sep-Pak cartridge in 40-65% radiochemical yields.
Carbon-11 labeled biaryl 1,2,3,4-tetrahydroisoquinoline derivatives and conformationally flexible analogues, 2-(2-(biphenyl-4-yl)ethyl)-6-[(11)C]methoxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline ([(11)C]3); 1-(biphenyl-4-yl)methyl-6,7-dimethoxy-2-[(11)C]methyl-1,2,3,4-tetrahydroisoquinoline (N-[(11)C]7) and 1-(biphenyl-4-yl)methyl-6-[(11)C]methoxy-7-methoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline (O-[(11)C]7); and 2-(biphenyl-4-yl)-N-(3,4-dimethoxy-phenethyl)-N-[(11)C]methyl-ethanamine (N-[(11)C]10) and 2-(biphenyl-4-yl)-N-(3-methoxy-4-[(11)C]methoxy-phenethyl)-N-methyl-ethanamine (O-[(11)C]10), have been synthesized as new potential positron emission tomography (PET) glioma tumor imaging agents, either by O-[(11)C]methylation or by N-[(11)C]methylation of the appropriate precursors using [(11)C]CH(3)OTf and isolated either by a simplified solid-phase extraction (SPE) purification procedure or by HPLC method in 30-55% radiochemical yields decay corrected to EOB, 15-25 min overall synthesis time, and 4.0-6.0 Ci/mumol specific activity at EOB.
We synthesized a novel (18)F-labeled dopamine D(4) receptor antagonist (Ki=4.3 nM), 3-(4-[(18)F]fluorobenzyl)-8-methoxy-1,2,3,4-tetrahydrochromeno[3,4-c]pyridin-5-one ([(18)F]FMTP), which has exhibited high affinity and selectivity. Radiosyntheses were accomplished by the reaction of fluorine-18-labeled intermediate with 8-methoxy-1,2,3,4-tetrahydrochromeno[3,4-c]pyridin-5-one (1) followed by HPLC purification. The overall radiochemical yield of the radiosynthesis was 19.5% (decay corrected), the specific radioactivity was about 110 GBq/micromol and the radiochemical purity was greater than 99%, the time of synthesis and purification was approximately 110 min. Tissue distribution studies of the [(18)F]FMTP in rats showed that the radioactivity in the brain was concentrated in frontal cortex and medulla, the region that has a high density of D(4) receptors. Pre-treatment with nonradioactive FMTP (1.0mg/kg) produced a significant reduction of radioactivity in all the regions. About 40% of total radioactivity in plasma and 100% in rat brain extract represented unchanged radioligand at 60 min after injection as determined by HPLC. These results indicate that [(18)F]FMTP have some specific binding to the D(4) receptor.
The synthesis of two novel radiolabelled estrogen derivatives, [125I](E)-3-methoxy-17alpha-iodovinylestra-1,3,5(10),6-tetraen-17beta-ol (E[125I]IVDE) and [125I](Z)-3-methoxy-17alpha-iodovinylestra-1,3,5(10),6-tetraen-17beta-ol (Z[125I]IVDE), was carried out aiming to study the influence of the introduction of a C6-C7 double bond on the biological properties of the estradiol molecule. 3-Methoxyestra-1,3,5(10),6-tetraen-17-one was synthesised starting from a suitably protected estrone and subsequently converted into the 17alpha-ethynyl derivative. The radioiodinated derivatives were stereoselectively formed by radioiododestannylation of the corresponding tributylstannyl precursors. The biodistribution of the novel [125I]iodovinylestradiol derivatives was evaluated in immature female mice. Biological data indicated that the Z-isomer, owing to its higher in vivo uptake by the target tissue, has the preferable configuration for further development of similar compounds for estrogen receptor detection.
As a possible radioligand for SPECT visualization of the NMDA receptors in the central nervous system, 7-chloro-5-[123I]iodokynurenic acid was prepared. This paper presents the synthesis of both the radioactive and the non-radioactive product, starting from 5-bromo-7-chlorokynurenic acid and using a non-isotopic nucleophilic halogen exchange reaction in the presence of iodide (Na123I or KI). Under the best labelling conditions, the radiochemical yield was 85%. The specific activity based on UV detection was found to be higher than 1 Ci/mumol (= 37 GBq/mumol) and the chemical and radiochemical (> 95%) purity of the tracer was checked by RP-HPLC.
A radiation-sensitive compound 2,4-hexadiyn-1,6-bis(n-butyl urethane) (HDDBU) was synthesized, characterized by FTIR spectroscopy, and introduced into a thin polyvinyl butyral film to form a radiation dosimeter for industrial irradiation facilities. The monomer polymerizes under gamma radiation, inducing change in the film spectrum in the range of 200-400nm. According to XRD spectroscopy, the film contains monomeric HDDBU in a non-crystalline state. The dose response function, radiation sensitivity, and dependences of the response on environmental factors were studied. Uncertainty of dose measurements with the proposed dosimetry system was analyzed in detail.
The relative intensities of different gamma emissions produced after the reaction (115)In(n,gamma)(116)In were analyzed for the particular case of incident neutron energies around the 1.45 eV indium absorption resonance. For this purpose, a pulsed neutron source in combination with the time-of-flight method for selecting the incident neutron energy range was employed. For neutrons around the mentioned absorption resonance the prompt gamma spectrum was extended to energies below 273 keV, and the intensities of gamma emissions not reported in the literature for epithermal neutrons were determined.
The response functions of a 7.62 x 7.62 cm NaI(Tl) scintillation detector to photons from point gamma-ray sources, 10 cm from the scintillator surface, in the energy up to 1.5 MeV, were calculated using the Monte Carlo method, applying simple approximations based on the peak to total ratio and the detector resolution. The Compton continuum of the detector response function was assumed as an isotropic (rectangular) region for the photon energies up to 1 MeV. In the energies between 1 and 1.5 MeV, the Compton continuum was obtained assuming a single Compton scattering with free electrons. The photopeak of the detector response function was assumed as a line. Each determined channel of the response function was distributed to Gaussian functions. The obtained response functions were compared with the experimental values and a good agreement was found.
For the design and modeling of Accelerator Driven sub-critical System (ADS) a detailed study of response of ADS materials to the spallation neutrons is required. For this purpose reaction rates of different reactions like (n, xn) and (n, xnyp) in 209Bi, natMo, 56Fe, natNi, 55Mn, natTi and natCo materials are determined in an experiment conducted at Nuclotron of JINR, Dubna, using 1.6 GeV d-beam in the 'Energy+Transmutation' set-up. Reaction rates of various (n, xn) and (n, xnyp) reactions are studied in these samples. Results of reaction rates deduced from all the gamma peaks observed in case of 209Bi (n, xn) reactions with x=3-9, natMo (n, γ), (n, 3n), (n, 6n), 56Fe (n, p), (n, p2n), (n, p4n), natNi (n, 2n), (n, 3n), (n, p), (n, d), (n, t), 55Mn (n, γ), (n, 2n), (n, 4n), natTi (n, p), (n, d), (n, t) and natCo (n, γ), (n, xn) reactions with x=2-5 along with (n, p), (n, 2p2n), (n, 2p4n) and (n, 2p6n) are presented. The measured reaction rates for all the elements show good consistency for all the reaction channels and all observed Eγ's of the product nucleus. For all the above mentioned reactions, both experimental as well as theoretical spectrum average cross-sections (σsp.av.cs) are deduced and compared. A close agreement is found between the experimental σsp.av.cs and theoretical σsp.av.cs values.
[Carbonyl-(11)C]WAY-100635 is a potent and effective antagonist for the 5-HT(1A) receptor subtype. We aimed to assess the status of [carbonyl-(11)C]WAY-100635 and its main radio-metabolites, [carbonyl-(11)C]desmethyl-WAY-100635 and [carbonyl-(11)C]cyclohexanecarboxylic acid, on the basis of an improved radio-HPLC method. Common methods were characterized by preparative HPLC columns with long runtimes and/or high flow rates. Considering the short half-life of C-11, we developed a more rapid and solvent saving HPLC assay, allowing a fast, efficient and reliable quantification of these major metabolites.
A fully automated synthesis of the important 5HT(1A) receptor radioligand, [carbonyl-(11)C]WAY-100635 (I), was developed based on the optimized one-pot "wet" synthesis procedure. A modern automated apparatus was constructed from commercially available components and operated via LabView software. In average, (906+/-525)MBq (n=94) of (I) was obtained from 40 min bombardment at 50 microA beam current within 50 min synthesis time. The specific radioactivity (SA) at the time of injection was (50.5+/-29.3)GBq/mumol (n=94).
An improved one-pot synthesis procedure for routine production of [carbonyl-(11)C]desmethyl-WAY-100635 ([(11)C]DWAY) is described. An efficient purification of the crude product has also been developed and was accomplished by C-18 reversed-phase semi-preparative HPLC using 55/45 EtOH-NaH(2)PO(4) buffer (20 mM, pH=6.5) as the eluent. The desired product fraction was collected in a 2.0-2.5 mL volume and formulated with 11 mL of 0.9% saline. The radioligand was ready for human use in 45 min (EOB). The product was obtained with a radiochemical yield of 11.1+/-1.8% (EOB, n=15) with a radiochemical purity of >99%. Specific activity was 133.2-185.0 GBq/micromol (3.6-5.0 Ci/micromol, EOS, n=2) when ca. 37.0 GBq (ca. 1.0 Ci) of starting [(11)C]CO(2) was used. Unlabeled mass of [(11)C]DWAY was found to be 0.15-0.24 microg/mL and the precursor was present in less than 50 ng/mL in final production solution.
Aim of this work was the implementation of a generalized in-loop synthesis for (11)C-carboxylations and subsequent (11)C-acylations on the TRACERlab FxC Pro platform. The set-up was tested using [carbonyl-(11)C]WAY-100635 and, for the first time, [(11)C]-(+)-PHNO. Its general applicability could be demonstrated and both [carbonyl-(11)C]WAY-100635 and [(11)C]-(+)-PHNO were prepared with high reliability and satisfying outcome.
We report on the application of the PILATUS 100K pixel detector for medical imaging. Experimental results are presented in the form of X-ray radiographs using standard X-ray absorption contrast and a recently developed phase contrast imaging method. The results obtained with the PILATUS detector are compared to results obtained with a conventional X-ray imaging system consisting of an X-ray scintillation screen, lens optics, and a charge coupled device. Finally, the results for both systems are discussed more quantitatively based on an image power spectrum analysis.
Activation cross sections of deuteron induced nuclear reactions on enriched (100)Mo have been studied up to 50 MeV using the stacked foil irradiation technique and gamma spectroscopy. The excitation functions for production of (99m)Tc, (ind99)Mo, (ind98m)Nb, (ind97mg)Nb radioisotopes were measured for the first time and compared with the results of the ALICE-D, EMPIRE-D and TALYS codes. Production possibilities of the medically important (99m)Tc are discussed.
The quadrupole deformations for the low-lying states in the transitional nuclei 100,101Pd have been deduced through the measurement of their electric quadrupole transition probabilities using the Recoil Distance Doppler Shift Method. The nuclei were studied using a 268 MeV 80Se beam impinging on a thin, self-supporting 24Mg target. States in 100Pd and 101Pd populated by the four and three neutron evaporation channels respectively, with reaction gamma-rays detected using the SPEEDY gamma-ray detection array. The recoiling nuclei were stopped in a copper foil and gamma-ray coincidence data taken at 10 separate target-stopper distances between 35 μm and 750 μm. The mean-lifetimes for the lowest lying 2+ (in 100Pd) and 15/2- (in 101Pd) states were measured to be 13.3(9) ps and 10.8(8) ps respectively. These data are compared with predictions from nuclear Total Routhian Surface calculations, which are found to agree with the experimentally deduced values to within 10%.
Excitation functions were determined by the stacked-foil and induced radioactivity measurement technique for the reactions (100)Ru(alpha,n)(103)Pd, (101)Ru(alpha,2n)(103)Pd, (101)Ru((3)He,n)(103)Pd, and (102)Ru((3)He,2n)(103)Pd, producing the therapeutic radionuclide (103)Pd, and for the reactions (101)Ru((3)He,x)(101 m)Rh(Cum) and (102)Ru((3)He,x)(101 m)Rh(Cum), producing the medically interesting radionuclide (101 m)Rh. Data were also measured for the reactions (101)Ru((3)He,pn+d)(102 m,g)Rh, (102)Ru((3)He,p2n+dn+t)(102 m,g)Rh, (101)Ru((3)He,x)(101 g)Rh(Cum), (102)Ru((3)He,x)(101 g)Rh(Cum), (101)Ru((3)He,3n)(101)Pd, (102)Ru((3)He,4n)(101)Pd, (101)Ru((3)He,4n)(100)Pd, and (101)Ru((3)He,p3n+d2n+tn)(100)Rh, producing other palladium and rhodium isotopes/isomers. The energy ranges covered were up to 25 MeV for alpha-particles and up to 34 MeV for (3)He ions. The radioactivity of the radionuclide (103)Pd induced in thin metallic foils of the enriched ruthenium isotopes was measured by high-resolution X-ray spectrometry and the radioactivities of other radionuclides by gamma-ray spectrometry. The integral thick target yields of the radionuclide (103)Pd calculated from the excitation functions of the first four of the above-named reactions amount to 960, 1050, 50, and 725 kBq/microAh, respectively, at the maximum investigated energies of the incident particles. The integral thick target yields of the radionuclide (101 m)Rh amount to 16.1 and 2.9 MBq/microAh for (101)Ru and (102)Ru targets, respectively, at 34 MeV energy of incident (3)He ions. The integral yields of the other observed radionuclides were also deduced from the excitation functions of the above-mentioned respective nuclear reactions. The excitation functions and integral yields of some rare reaction products were also determined. The experimental excitation functions of some reactions are compared with the predictions of nuclear model calculations. In general, good agreement was obtained.
Beta-decay half-lives of the ground state and an isomer of 102Rh have been determined 207.3(17) d and 3,742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2-) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.
A new (103)Pd plastic brachytherapy source, OptiSeed(TM) Model 1032P, is being introduced by International Brachytherapy sa (IBt). Measurements of the dose distributions about the source were performed using LiF thermoluminescent dosimeters (TLD-100) in Virtual Water(TM). MCNP5 calculations were performed to determine the dose distributions in Virtual Water(TM) and liquid water. The source dose rate constant, radial dose function, anisotropy function and anisotropy factor have been determined following the updated AAPM TG-43 recommendations. The measured dose rate constant in the Virtual Water(TM) phantom was determined to be 0.727+/-6.9% cGyh(-1)U(-1), and the computed value is 0.716+/-2.1% cGyh(-1)U(-1). The Monte-Carlo simulation yielded a dose rate constant of 0.665+/-2.1% cGyh(-1)U(-1) in water. The measured dose rate constant in water is 0.675+/-7.5% cGyh(-1)U(-1). It is determined by multiplying the dose rate constant measured in the Virtual Water(TM) phantom with the ratio of the value calculated in water to that in Virtual Water(TM). The average of the measured and calculated dose rate constant is 0.670+/-5.5% cGyh(-1)U(-1). The radial dose functions of the new source were measured for distances ranging from 1 to 7 cm in a Virtual Water(TM) phantom. The anisotropy functions in Virtual Water(TM) phantom were measured for distances of 2, 3, 5, and 7 cm. The Monte-Carlo computed radial dose functions, anisotropy functions, and anisotropy factors in both Virtual Water(TM) phantom and water are reported.
Palladium 103 is a radionuclide used in brachytherapy sources for the treatment of prostate cancers and also for other medical applications. It decays through electron capture to excited levels of 103Rh. This paper describes the calculation method used to compute the detection efficiency in the framework of the triple to double coincidence ratio model. The calculation of the energy transferred to the scintillator is made by considering the various atomic events following the electron capture and the electron conversion. The energy deposited in the scintillator after the absorption of X-rays is calculated using the PENELOPE stochastic calculation code. The main contributors to the final uncertainty and their covariance matrix are discussed. As the calculation method cannot be reduced to an explicit function, this paper describes the Monte Carlo method used for the evaluation of uncertainties.
Dosimetric characteristics of the BrachySeed Pd-103, Model Pd-1 source have been determined using both theoretical and experimental methods. Dose rate constant, radial dose function, and anisotropy functions of the source have been obtained following the TG-43 recommendations. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with their 1999 Standard. Measurements were performed in Solid Water using LiF TLD chips. Theoretical simulation calculations were performed in both Solid Water and water phantom materials using MCNP4C2 Monte Carlo code using DLC-200 interaction data. The results of the Monte Carlo simulation indicated a dose rate constant of 0.65 cGyh(-1)U(-1) and 0.61 cGyh (-1)U(-1) in water and Solid Water, respectively. The measured dose rate constant in Solid Water was found to be 0.63+/-7% cGyh (-1)U(-1), which is within the experimental uncertainty of the Monte-Carlo simulated results. The anisotropy functions of the source were calculated in both water and in Solid Water at the radial distances of 1 to 7 cm. Measurements were made in Solid Water at distances of 2, 3, 5, and 7 cm. The Monte-Carlo calculated anisotropy constant of the new source was found to be 0.98 in water. The tabulated data and 5th order polynomial fit coefficients for the radial dose function along with the dose rate constant and anisotropy functions are provided to support clinical use of this source.
A method for 103Pd "molecular plating" onto the surface of a silver rod is reported. The optimal composition of the plating bath is as follows: palladium chloride 0.1 mol/l, formaldehyde 2 mol/l, nitric acid 1 mol/l, and formic acid 0.4 mol/l. The 103Pd molecular plating procedure will last 25 min at 30 degrees C. This article provides a valuable experience for the preparation of 103Pd brachytherapy seed.
ADVANTAGE Pd-103 brachytherapy source has been recently introduced by IsoAid for prostate permanent implants. Dosimetric characteristics (Dose rate constant, radial dose function, 2D-, and 1D-anisotropy functions) of this source model have been determined using both theoretical and experimental methods, following the updated TG-43U1 protocol. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with the 1999 Standards. Measurements were performed in Solid Water using LiF TLD chips and the theoretical calculations were performed in Solid Water and liquid water phantom materials using PTRAN Monte Carlo code. The results of the Monte Carlo simulation have shown a dose rate constant of 0.69 cGyh(-1) U(-1) in liquid water and 0.67 cGyh(-1) U(-1) in Solid Water medium. The measured dose rate constant in Solid Water was found to be 0.68+/-8% cGyh(-1) U(-1), which is in a good agreement (within +/-5%) to the Monte Carlo simulated data. The 2D- and 1D-anisotropy functions of the ADVANTAGE Pd-103 source were calculated for radial distances ranging from 0.5 to 5.0 cm. Radial dose function was determined for radial distances ranging from 0.2 to 8.0 cm using line source approximation. All these calculations are based on L(eff) equal to 3.61 cm, calculated following TG-43U1 recommendations. The tabulated data for 2D-anisotropy function, 1D-anisotropy function, dose rate constant and radial dose function have been produced for clinical application of this source model.
Electroplated rhodium foil was employed as the target for cyclotron production of palladium-103. An electrodissolution apparatus was found better than other dissolution methods in terms of personnel shielding and palladium-103 yield. The ion-exchange column chromatography method was simple and effective for the purification of palladium-103 and the final stripping agent of NH4Cl + NH3(1:1) was more efficient than other agents.
TG-43U1 dosimetric parameters of a new brachytherapy (103)Pd source, including dose-rate constant, radial dose function, 2D anisotropy function, 1D anisotropy function and anisotropy constant, have been determined using MCNP4C code and have been verified by measurements in Perspex phantoms, using TLD-100 dosimeters calibrated in (60)Co radiation field. The comparison of calculated and measured dosimetric parameters showed the validity of Monte Carlo calculations and experimental results. The anisotropy constant was calculated as 0.87 in water and 0.88 in Perspex; and measured as 0.92 in Perspex. Comparing dosimetric parameters of the new source with other source models showed acceptable agreement.
(103)Pd is an important radionuclide having a half-life of 16.99d, which is suitable for internal radiation therapy, especially used for the treatment of prostate cancer. Its production in no-carrier-added form is done via charged-particle-induced reactions and the data are available in EXFOR library. We evaluated six charged-particle-induced reactions, namely (nat)Ag(p,x)(103)Pd, (103)Rh(p,n)(103)Pd, (103)Rh(d,2n)(103)Pd, (100)Ru(alpha,n)(103)Pd, (101)Ru(alpha,2n)(103)Pd, and (102)Ru((3)He,2n)(103)Pd process. In the first case, analysis was done up to about 100MeV but in other cases only up to about 25 or 40MeV. Furthermore, an evaluation of the data for the (nat)Ag(p,x)(103)Ag process was also done since it may serve as a typical example for the (103)Ag-->(103)Pd precursor system. A statistical procedure supported by nuclear model calculations using the codes STAPRE, EMPIRE 2.19, and TALYS was used to validate and fit the experimental data. The recommended sets of data derived together with confidence limits are reported. The application of those data, particularly in the calculation of integral yields, is discussed. A comparison of the investigated routes from the viewpoint of practical applicability to the production of (103)Pd is given. Presently the (103)Rh(p,n)(103)Pd reaction is the method of choice.
The use of Auger emitters as potential radiopharmaceuticals is being increasingly investigated. One of the radionuclides of interest is (103m)Rh, which can be produced from (103)Ru or (103)Pd in an in vivo generator. A potential problem, however, is the recoil of the (103m)Rh out of the carrier molecule and even out of the target cell. In order to determine the likelihood of this happening in the (103)Pd/(103m)Rh, case calculations were made to prove that this does not happen. The equations were generalised for all radionuclides with an atomic mass of 10-240 as a tool for determining the recoil threshold of any beta-emitting radionuclide.
The use of Auger emitters as potential radiopharmaceuticals is increasingly investigated. One such radionuclide of interest is (103m)Rh. This can be produced from (103)Ru or from (103)Pd in an in vivo generator. A potential problem with this concept is the recoil of the (103m)Rh out of the carrier molecule and even out of the target cell. In order to determine whether this would happen in the (103)Pd/(103m)Rh case calculations were done to prove that this does not happen. From theoretical considerations it seems that the (103)Pd/(103m)Rh in vivo generator system would be possible.
It is of interest to discern the energy-dependence of American Association of Physicists in Medicine (AAPM) TG-43 brachytherapy dosimetry parameters. Using Monte Carlo calculation geometry and techniques (MCNP), dependence of these parameters was calculated as a function of photon energy, in general, and for the MED3633 103Pd source using a discretized approach. Results were weighted and summed to determine the total contribution for comparison with the 103Pd source literature. Comprehensive 2-D results are discussed, and the level of agreement with other assessments are presented.