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Sample records for autoradiolysis

  1. After-effects of electron capture of 57Co in Fe(ClO4)2x6H2O and Fe(BF4)2x6H2O

    International Nuclear Information System (INIS)

    Moesbauer emission and absorption spectra of ferrous hexahydrates show no difference in the phase transformation temperature but the quadrupole splitting of ferrous ions is by 13% less in the emission case. Probably, this can be attributed to the autoradiolysis of water ligands resulting in the formation of a metastable state of the molecule. Time delayed coincidence Moessbauer measurements show the lifetime of this state to be in the order of 10-8-10-7s. (author)

  2. Two newly developed methods for the radioactive labeling of tetanus toxins with substances emitting beta-rays and the usefulness of the compounds thus obtained in radioimmunoassays to determine tetanus antibodies

    International Nuclear Information System (INIS)

    Described are two methods to label tetanus toxins using either 14C-formaldehyde or succinimidyl-3H- propionate as radioactive tracers. The question as to whether the labeled compounds thus obtained can be introduced into RIAs for the detection of tetanus antibodies is also discussed. The immunoreactivity of 3H-toxin is not perceptibly changed by the labeling procedure. The compound can be compared to 125I-labeled toxin, although it suffers no adverse effects from long-term due to autoradiolysis. (TRV)

  3. Preparation of 19-iodocholestrol labelled with I-125 and its study as a 'tracer' of plasma lipoprotein

    International Nuclear Information System (INIS)

    A technique of synthesis of the 19-iodocholesterol labelled with I-125, modified in some steps from other methods published previously, is described. We have obtained a product with high chemical (96%) and radiochemical (99,9%) purities. The yield was higher and the time necessary to prepare it was lower than other methods reported. The study of thermal and radiolytic stability showed that the 19-iodocholesterol-I-125 was not broken by autoradiolysis whereas the I-125 was separated from the molecule when the temperature was increased. The use of this 19-iodocholesterol-I-125 as a tracer of cholesterol of plasma lipoprotein showed some properties of LCAT and CETP and also showed the different capacity of VLDL and LDL to transport cholesteryl esters. (author) 105 refs

  4. Container for the transport and dosable removal of radioactive and/or toxic media

    International Nuclear Information System (INIS)

    The transport container can be used, e.g., to move organically bound or elemental iodine to nuclear ventilation systems where the gases are to be fed into these systems as test agents. The container accomodating the first of which, which comes next to the gas container, is designed as a shield. For this purpose, the space between the gas container and the shielding vessel is filled with lead shot. The shielding vessel is surrounded by the second protection vessel at some distance; the interior of the second vessel can be evacuated or scavenged with gas, respectively. The instruments are installed in the two protection vessels. Since the transport volume is relatively large, autoradiolysis of the test gas can be reduced. In addition, the protection vessels can be kept in a transport crate together with a wheelframe. (orig.)

  5. After-effects of electron capture of 57Co in frozen aqueous solutions of 57CoCl2

    International Nuclear Information System (INIS)

    Moessbauer spectra of 57Co in dilute frozen aqueous solutions of 57CoCl2 and in 0.11 at.% frozen aqueous solutions of CoCl2 with and without glass former have been studied. The spectra reveal the presence of a small fraction of Fe3+ ions besides the Fe2+ as a consequence of the Auger cascade following the electron capture. The addition of glycerol to the 57CoCl2 solution resulted in decreasing the fraction of Fe3+. The quadrupole splitting of the ferrous ions was found to be less by 13% than that of the Fe(H2O)62+ complex as measured in absorption geometry. This is suggested as being the consequence of the autoradiolysis of water molecules resulting in a metastable state of the complex. (orig.)

  6. Radiation and chemical stability of 2-deoxy-2-[18F]fluoro-D-glucose radiopharmaceutical. Author-review of thesis

    International Nuclear Information System (INIS)

    A qualitative and quantitative analytical technique of low-molecular components of chemical and radiation-chemical decomposition of 2-deoxy-2-[18F]fluoro-D-glucose, 2-[18F]FDG radiopharmaceutical was developed for its extended quality control by HPLC with mass-spectrometric electro-spray ionisation detector (ESI MS). The analysis constituted from the liquid chromatography on silica gel NH2 bonded column combined with mass-spectrometric, UV-VIS, refraction index and radiometric detectors. A modern LC/MS system (Agilent 1100) was demonstrated to be suitable not only for identification of unknown analytes, but also for complex analysis of solutes except [18F]F-. This was advantageous for the 2-[18F]FDG autoradiolysis assessment about which no data were published. For comparative purposes, were used a classic thin layer chromatography (TLC) on silica gel with mobile phase acetonitril: water at 95:5 v/v, and HPTLC on NH2 modified silica gel like the LC column. Mobile phase was identical as by LC/MS method (acetonitril: 4 mM aqueous solution of ammonium formate 80:20 v/v). Retention times of reference samples: fluorodeoxyglucose, glucose, mannose, arabinose, deoxyglucose, gluconic and glucuronic acids at HPLC were established. Optimal performance of the ESI MS detector was discovered in negative ions mode or single ion monitoring (SIM) regime. The most intensive signal was observed for all analyte molecules association with formate anion HCOO- and also for negative ions of deprotonised molecules. All acids appeared in the form of their lactones. FDG and Glc exhibited tendency for formation of a mixed associate charged by HCOO- anion. On the amine bond silica gel HPTLC column, FDG is poorly separated from fluoride, which even in presence of Kryptofix 2.2.2 remains on the start like on the silica gel layer. At LC-MS Kryptofix provides a very well measurable signals of associates with NH4+ a H+ ions in positive mode of ESI MS. Concentration of (19F)FDG carrier in 2-[18F

  7. Radiation and chemical stability of 2-deoxy-2-[18F]fluoro-D-glucose radiopharmaceutical

    International Nuclear Information System (INIS)

    Qualitative and quantitative analytical technique of low-molecular components of chemical and radiation-chemical decomposition of 2-deoxy-2-[18F]fluoro-D-glucose, 2-[18F]FDG radiopharmaceutical was developed for its extended QC by HPLC with mass-spectrometric electro-spray ionisation detector (ESI MS). The analysis constituted from the LC on silica gel NH2 bonded column combined with MS, UV-VIS, refraction index and radiometric detectors, and TLC on silica gel and high-performance TLC (HPTLC) on silica gel NH2 bonded as at the LC column. Condition of analysis, the composition of mobile phase at HPLC and the regime of ESI MS were optimised on the maximal intensity of the signals of analytes, which were predicted for commercial 2-[18F]FDG and its decomposition products. A modern LC/MS system was demonstrated to be suitable not only for identification of unknown analytes, but also for complex analysis of solutes except [18F]F-. This was advantageous for the 2-[18F]FDG autoradiolysis assessment about which no data were published. For comparative purposes, were used a classic TLC on silica gel with mobile phase acetonitrile: water at 95:5 v/v, and HPTLC on NH2 modified silica gel like the LC column. Mobile phase was identical as by LC/MS method (acetonitrile: 4 mM aqueous solution of ammonium formate 80:20 v/v). Retention times of reference samples: fluorodeoxyglucose, glucose, mannose, arabinose, deoxyglucose, gluconic and glucuronic acids at HPLC were established. Equal composition of the inlet sample and mobile phase was found important to avoid increased background of the MS detector and asymmetry of the chromatographic peaks. Reference substance detectability was investigated for various detectors. Characteristic ions were established for the analytes under consideration. Optimal performance of the ESI MS detector was discovered in negative ions mode or single ion monitoring (SIM) regime. The most intensive signal was observed for all analyte molecules association

  8. Gallium-67/Gallium-68-[DFO]-octreotide-a potential radiopharmaceutical for PET imaging of somatostatin receptor-positive tumors: Synthesis and radiolabeling in vitro and preliminary in vivo studies

    International Nuclear Information System (INIS)

    When labeled with gamma-emitting radionuclides, somatostatin analogs have the potential to localize somatostatin receptor-positive tumors using gamma camera scintigraphy. The authors present a somatostatin analog, [DFO]-octreotide (SDZ 216-927), that comprises desferrioxamine B coupled to octreotide via a succinyl linker. This conjugate can be labeled with either 67Ga-labeled conjugate is stable in vitro to autoradiolysis over a 24-hr period. Rats bearing a somatostatin receptor-positive pancreatic islet cell tumor were injected with 20 MBq of 67Ga[DFO] octreotide (33 GBq 67Ga/μmole). After 1 hr, the accumulation of 67Ga[DFO]-octreotide was 0.38 ± 0.08 %ID/g and the tumor-to-nontumor ratios for blood, muscle, liver and intestine were 2.5, 7.4, 1.98 and 1.6, respectively. PET studies with 68Ga[DFO]-octreotide recorded a very rapid accumulation at the tumor and a subsequent residence half-life of about 6 hr. Gallium-68-[DFO]-octreotide can be used in PET studies to diagnose receptor-positive tumors such as gastroentero-pancreatic, small-cell lung and breast tumors. 40 refs., 7 figs., 3 tabs

  9. The study of labeling with iodine-131 of monoclonal antibody anti-CD20 used for the treatment of non-Hodgkin lymphoma

    International Nuclear Information System (INIS)

    Lymphomas are malignancies of the lymphatic system, described by Thomas Hodgkin in 1932. Traditionally, lymphomas are classified in two basic groups: Hodgkin disease and non-Hodgkin lymphoma (NHL). Patients with NHL were earlier treated with radiotherapy alone or in combination with immunotherapy using monoclonal antibody anti-CD20 (ex., Rituximab-Mabthera, Roche). However, Radioimmunotherapy is a new modality of treatment for patients with NHL, in which cytotoxic radiation from therapeutic radioisotopes is delivered to tumors through monoclonal antibodies. This study focused on labeling conditions of monoclonal anti-CD20 (ex., Rituximab-Mabthera, Roche) with iodine-131, by direct radioiodination method using Chloramine-T as oxidizing agent. Labeling parameters investigated were: Radiochemical purity (RP), method of purification, incubation time, antibody mass, oxidative agent mass, stability in vitro, immunoreactivity and biological distribution performed in normal Swiss mouse. Product of high radiochemical purity was obtained with no notable difference between the methods applied. No clear evidence of direct influence of incubation time on radiochemical purity of the labeled antibody was observed. Whereas, a clear evidence of direct influence of activity on radiochemical purity of the labeled antibody was varied. After purification the labeled product presented radiochemical purity of approximately 100 %. Product of superior radiochemical yield was observed when standard condition of labeling was used. The labeled product presented variation in radiochemical purity using five different stabilizer conditions. The condition in which gentisic acid combined with freeze appears more suitable and capable of minimizing autoradiolysis of the antibody labeled with freeze appears more suitable and capable of minimizing autoradiolysis of the antibody labeled with high therapeutic activity of iodine-131. The labeled product presented low immunoreactivity when compared to the

  10. HPLC-MS technique in radiopharmaceutical research (the quality control of 18F-2-fluorodeoxyglucose as an example)

    International Nuclear Information System (INIS)

    Application of radiopharmaceuticals puts increasing demands on their quality control, considering the short half-times, high specific activities (auto-radiolytic effects), and general quality (chemical purity, apyrogenity and sterility) of pharmacy. Mostly, the radioanalytical control consists of application of several separation and instrumental analytical techniques. In this paper, perspective of the hyphenated HPLC and MS techniques is demonstrated on the example of one of the most spread radiopharmaceutical, 2-[18F]fluoro-2-deoxy-D-glucose (further as FDG). In this work, a liquid chromatography/refractive index detector/radiometric detector/mass spectrometric detector combination (HPLC/RID/RAD/MSD) was used for development of a complex routine technique. Optimization of HPLC/MS analysis was performed investigating the electrospray ionization (ESI) analytical signal of mass spectrometer as a function of various eluent composition (see this book, p. 39). Some results, illustrating the glucose and FDG ESI-MS, and also composition of FDG after autoradiolysis, which were obtained either by a TOF Mariner (Perkin Elmer) mass-spectrometer and Agilent 1100 HPLC-MS equipment with quadrupole MS detector are discussed. They give evidence of admixtures and radiolytic formation of deoxyglucose, deoxychloroglucose, erythrose, erytritol, gluconic acid, lactose, raffinose, saccharic acid, sorbitol/[19F]FDG, xylitol, and also univalent ions of C6H10O7F.H2O and C6H12O8 compounds. The results indicate that the emerging demands on radiopharmaceuticals quality control can be fulfilled in-time only by the radio-HPLC technique developed by the help of a tandem mass-spectrometric detector. (authors)

  11. Investigations of the chemical consequences of radioactive decay of iodine 125 and tritium in labelled pyrimidine bases using the double labelling technique and ESR spectroscopy

    International Nuclear Information System (INIS)

    In the present work, the chemical secondary reactions of the radioactive decay (K capture) of I 125 in solutions of the synthetic DNA forerunner iodouracil were investigated with the aim to interpret the large radiotoxicity of DNA-bonded I 125 by procedures at molecular level. Furthermore, the radical formation as a result of the decay of tritium in 3H-labelled thymine and cytosine were also traced on a smaller scale. The chemical decay effects of molecular bonded iodine 125 was investigated using the double labelling technique (I 125 + C 14). After accumulation of the I 125 decays and hence the product molecules in aqueous solution at +20 or -1960C, the reaction products were radio-gas chromatographically separated or by means of high-pressure liquid chromatography and then analyzed. Radiolytic side effects were simultaneously determined by separate γ-irradiation experiments. The results show that due to the Auger effect as a result of the radioactive decay of 125I, a significantly greater destruction occurs in the immediate environment than can be achieved by external irradiation with γ-quanta. It could be shown for the first time, by detection of the volatile transmutation products CO and CO2, that drastic chemical consequences result for the molecule residue in the decay of molecular-bonded 125I even in the condensed phase. The β-autoradiolysis was also determined to be the main source of fragmentation in the case of tritium beta decay in thymine and cytosine. ESR investigations show distinct differences in the radical formation compared to external γ-radiolysis. (orig./RB)

  12. The study of labeling with Iodine-131 of monoclonal antibody anti-CD20 used for the treatment of non-Hodgkin lymphoma; Estudo de marcacao com Iodo-131 de anticorpo monoclonal anti-CD20 na terapia de linfoma nao-Hodgkin

    Energy Technology Data Exchange (ETDEWEB)

    Akanji, Akinkunmi Ganiyu

    2006-07-01

    Lymphomas are malignancies of the lymphatic system, described by Thomas Hodgkin in 1932. Traditionally, lymphomas are classified in two basic groups: Hodgkin disease and non-Hodgkin lymphoma (NHL). Patients with NHL were earlier treated with radiotherapy alone or in combination with immunotherapy using monoclonal antibody anti-CD20 (ex., Rituximab-Mabthera, Roche). However, Radioimmunotherapy is a new modality of treatment for patients with NHL, in which cytotoxic radiation from therapeutic radioisotopes is delivered to tumors through monoclonal antibodies. This study focused on labeling conditions of monoclonal antibody anti-CD20 (Rituximab-Mabthera, Roche) with iodine-131, by direct radioiodination method using Chloramine-T as oxidizing agent. Labeling parameters investigated were: Radiochemical purity (RP), method of purification, incubation time, antibody mass, oxidative agent mass, stability in vitro, stability in vivo, immunoreactivity and biological distribution performed in normal Swiss mouse. Product of high radiochemical purity was obtained with no notable difference between the methods applied. No clear evidence of direct influence of incubation time on radiochemical purity of the labeled antibody was observed. Whereas, a clear evidence of direct influence of activity on radiochemical purity of the labeled antibody was observed when antibody mass was varied. After purification, the labeled product presented radiochemical purity of approximately 100 %. Product of superior radiochemical yield was observed when standard condition of labeling was used. The labeled product presented variation in radiochemical purity using five different stabilizer conditions. The condition in which gentisic acid was combined with freeze appears more suitable and capable of minimizing autoradiolysis of the antibody labeled with high therapeutic activity of iodine-131. The labeled product presented low immunoreactivity when compared to the literature. Biological distribution in

  13. The preparation and its believable effect of pentavalent ruenium-188 dimercaptosuccinic acid in a patient with medullary thyroid carcinoma

    International Nuclear Information System (INIS)

    Background: Dimercaptosuccinic acid (DMSA) forms a complex with pentavalent rhenium-188, known as 188Re(V)-DMSA. This radiopharmaceutical has been shown to localize in a number of tumour types, most notably medullary thyroid carcinoma (MTC) and in bone metastases and other bone lesions. We have previously shown that 186Re(V)-DMSA could be strongly uptaked by the lesion of MTC similar to that observed in the images of 99mTc(V)-DMSA and had potential therapeutic value in these patients. Compared with 186Re, the 188Re has the advantages of its ready availability from a generator. Thus the aim of this study was to establish a method of reliable preparation of 188Re(V)-DMSA and to evaluate its potential as a targeted radiotherapy agent to patient with MTC. Material and Method: The complex was prepared by reducing 188Re in the presence of DMSA with stannous chloride at the condition of pH 1.5. The reaction was taken to completion by heating the complex in a boiling water bath for 30 minutes. Excess stannous chloride was required and the presence of hydrochloric acid didn't reduce the yield of labelling. A large dose of ascorbic acid was used to minimize autoradiolysis. The products were analysed with high-performance liquid chromatograms (HPLC) and thin layer chromatography (TLC) using a mobile phase consisting of n-butanol: acetic: water = 3:2:3 by volume. The TLC chromatograms were also visualized and quantified by gamma camera imaging. With the agreement, a patient who had a liver metastatic lesion from MTC but no symptoms (patient I) and another who had bone metastatic MTC and severe symptoms (patient II) were recruited . Both volunteers confirmed by a prior 99mTc(V)-DMSA scan received a dose of 74 MBq of 188Re(V)-DMSA and imaged at 3 hours with a GE Millennium VG ECT/CT. Results: The preparation had a good results with a labeling rate more than 95% and a stability in vitro more than 24 hours. The complex was a clear yellow solution which can be adjusted to pH=7

  14. The study of labeling with Iodine-131 of monoclonal antibody anti-CD20 used for the treatment of non-Hodgkin lymphoma

    International Nuclear Information System (INIS)

    Lymphomas are malignancies of the lymphatic system, described by Thomas Hodgkin in 1932. Traditionally, lymphomas are classified in two basic groups: Hodgkin disease and non-Hodgkin lymphoma (NHL). Patients with NHL were earlier treated with radiotherapy alone or in combination with immunotherapy using monoclonal antibody anti-CD20 (ex., Rituximab-Mabthera, Roche). However, Radioimmunotherapy is a new modality of treatment for patients with NHL, in which cytotoxic radiation from therapeutic radioisotopes is delivered to tumors through monoclonal antibodies. This study focused on labeling conditions of monoclonal antibody anti-CD20 (Rituximab-Mabthera, Roche) with iodine-131, by direct radioiodination method using Chloramine-T as oxidizing agent. Labeling parameters investigated were: Radiochemical purity (RP), method of purification, incubation time, antibody mass, oxidative agent mass, stability in vitro, stability in vivo, immunoreactivity and biological distribution performed in normal Swiss mouse. Product of high radiochemical purity was obtained with no notable difference between the methods applied. No clear evidence of direct influence of incubation time on radiochemical purity of the labeled antibody was observed. Whereas, a clear evidence of direct influence of activity on radiochemical purity of the labeled antibody was observed when antibody mass was varied. After purification, the labeled product presented radiochemical purity of approximately 100 %. Product of superior radiochemical yield was observed when standard condition of labeling was used. The labeled product presented variation in radiochemical purity using five different stabilizer conditions. The condition in which gentisic acid was combined with freeze appears more suitable and capable of minimizing autoradiolysis of the antibody labeled with high therapeutic activity of iodine-131. The labeled product presented low immunoreactivity when compared to the literature. Biological distribution in