[en] Removal efficiency decreases with large amount of reagent K added and increases under 0.555 molar concentration of Mg⁺⁺. Optimum addition of reagent K was when molar concentration of Mg⁺⁺ becomes 0.186 (Ca⁺⁺ : Mg ⁺⁺ = 1 : 0.5). Sludge arising decreased about 40 ∼50% with reagent K added, and settling property becomes better due to high density. Effect of reagent K addition is the same in lime and limestone experiment. Addition of reagent K was a little more effective in the mixture than in the supernatant. Optimum pH and injection amount turned out to be 12 and 1 % v/v, respectively. It can be concluded that waste sludge resulting from SO_x removal with reagent K can be reused in the treatment of the industrial waste water such as dyeing waste water. (author). 9 refs., 5 tabs., 19 figs

[en] The chelating agent DOTA (1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) forms stable complexes with beta emitting radionuclides, and these specific complexes can be used to develop tumour targeting agents when coupled with biomolecules such as peptides and antibodies. The present study was aimed at developing techniques for labelling the biomolecule DOTATATE with radionuclides such as ¹⁶⁶Ho, ¹³¹I and ¹⁷⁷ Lu. The radioisotope ¹⁶⁶Ho, produced at the HANARO multipurpose reactor in the Republic of Korea, is a candidate for therapeutic use in cancer treatment because it has a 26.8 h half-life and decays with the emission of beta particles with energies of 1.77 MeV (48%) and 1.85 MeV (51%). Two other beta emitting nuclides, ¹³¹I and ¹⁷⁷Lu, were included in the study for comparison. It was established that, of the three radionuclides studied, the best for targeted radiotherapy was ¹⁷⁷Lu when complexed with DOTATATE. The present study focused on the development of techniques for labelling peptides with ¹⁶⁶Ho, as well as quality control procedures. The labelling yield of the radiopeptide and its radiochemical purity were determined by high performance liquid chromatography and instant thin layer chromatography. In vitro assays were carried out to determine the therapeutic efficacies of ¹⁶⁶Ho labelled peptides as a radiotherapeutic agent. (author)

[en] The Korea Atomic Energy Research Institute (KAERI) completed the High-flux Advanced Neutron Application Reactor (HANARO) in 1995 and the radioisotope production facilities(RIPF) in 1997. Many devices and handling tools were developed and applied for the production of radioisotopes. Emphasis on RI production plan was placed on the development of new radiopharmaceuticals, the development of new radiation sources for industrial use and the steady production of selected radioisotopes. The selected items are ¹⁶⁶Ho-based pharmaceuticals, fission ⁹⁹Mo/^99mTc generators, and products of ¹³¹I and ¹⁹²Ir and ⁶⁰Co sources for industrial use. Now KAERI regularly produces radioisotopes (¹³¹I, ^99mTc, ¹⁶⁶Ho, ¹⁹²Ir, ⁶⁰Co etc.) and labeled compounds including ^99mTc cold kits. Newly developed therapeutic agents are a ¹⁶⁶Ho-chitosan complex for liver cancer treatment, a ¹⁶⁶Ho patch for skin cancer treatment and devices such as the stent and balloon for the prevention against restenosis of the coronary artery. Feasibility studies on the installation of a ^99mTc generator loading facility and on ⁶⁰Co production for food irradiation were finished. The ¹⁹²Ir sealed source assembly for NDT has been supplied to domestic users since May 2001. The fission moly process, separation process of non-sealed sources (¹²⁵I, ³³P, ⁸⁹Sr, ¹⁵³Sm, ¹⁸⁸Re) and fabrication process of sealed sources (¹⁶⁹Yb, ⁷⁵Se) are also under development. For the quality assurance of final products, ISO certification was obtained in 2000. Feasibility study is carried out on a new research reactor for the stable supply of radioisotopes in Korea. (author)

[en] Full text: Brachytherapy is one of the effective treatments for in-stent restenosis. Filling the dilatation catheter balloon with radioactive solutions has the advantages of an accurate source positioning and uniform dose delivery to the vessel walls. In addition, it can be used easily with an existing catheter. Moreover, a solution based beta ray source allows for the treatment of large vessels. Of the variety of radioisotopes prepared in a soluble form for use as a liquid radiation source, Ho-166 is a good radioisotope, because it can be readily produced by irradiating a natural Ho target using a low or medium flux research reactor (¹⁶⁵Ho has 100% natural abundance). For X ray imaging, various iodinated X ray contrast agents having the 1,3,5-triiodobenzoic acid platform are used, mainly for computed tomography (CT) and angiographic applications. In the present study, we prepared a new DTPA bisamide derivative, DTPA-BTIPA (3-amino- 2,4,6-triiodoisophthalic acid) containing iodine in the structure. ¹⁶⁶Ho was labeled with DTPA-BTIPA as a possible agent for IVRT for the prevention of restenisis. The optimum condition of the radiolabeling of DTPA-BTIPA with Ho-166 was achieved by varying different reaction parameters. To estimate the ¹⁶⁶Ho-complex as a liquid radiation source for a potential clinical application of IVRT, which is readily excreted through the urinary system in the event of a balloon rupture, a dynamic imaging was acquired. ¹⁶⁶Ho-(DTPA- BTIPA) was prepared by a simple mixing at room temperature. High radiochemical stability (>98%) was maintained over a period of 6 h at room temperature. The radioactivity curve in the kidneys of the rabbit administered with ¹⁶⁶Ho-(DTPA-BTIPA) via an ear vein showed that the ¹⁶⁶Ho-(DTPA- BTIPA) was rapidly cleared through the kidneys. The average of T_max and T_1/2 of ¹⁶⁶Ho-(DTPA-BTIPA) in the kidneys were 2.26 ± 0.78 min and 7.80 ± 1.16 min, respectively. The serial static image scans of the rabbit administered with ¹⁶⁶Ho-complex revealed that none of the tissues except for the urinary system had radioactivity concentrations. Both the radiochemical and biological studies revealed that the ¹⁶⁶Ho labeled DTPA-BTIPA can be further investigated as a potential agent for vascular brachytherapy having the characteristic of a CT contrast. The use of the ¹⁶⁶Ho-DTPA-BTIPA for IVRT is a good alternative to see if the balloon has close contact with the blood vessel wall for the delivery of a sufficient radiation dose to the stenotic artery. (author)

[en] ^99mTc-MAG₃, a currently employed renal function diagnostic, is not ideal owing to its high plasma protein binding and complex synthetic procedure. Thus we developed ^99mTc tricarbonyl cysteine as a potential renal radiopharmaceutical and studied its biological characteristics in experimental animals. We synthesized ^99mTc tricarbonyl precursor and then prepared ^99mTc tricarbonyl cysteine to assess a new renal diagnostic agent. We assessed its labelling yield, biodistribution property in mice, and its dynamic imaging profiles in rabbits. Results obtained throughout the study were as follows: 1) ^99mTc(CO)₃(H₂O)₃⁺ was prepared with higher than 98% of synthetic yield, with the stability up to 8 hrs, and labelling yield of ^99mTc tricarbonyl cysteine was usually higher than 90%, on HPLC. 2) Biodistribution of ^99mTc tricarbonyl cysteine in ICR mice at 5 and 90 min showed very high accumulation in kidney and bladder, and almost 99% of ^99mTc tricarbonyl cysteine was excreted within 90 min post injection. ^99mTc tricarbonyl cysteine was rapidly excreted in vivo without any other residual concentration. 3) renogram of ^99mTc tricarbonyl cysteine in rabbits showed that its T_max (2.86 ± 0.88 min) and T_1/2 (3.78 ± 1.12 min) was similar to those of ^99mTc-MAG₃ (T_max: 1.76 ± 0.66 min; T_1/2: 2.57 ± 0.72). 4) T_max and T_1/2 of ^99mTc tricarbonyl cysteine in kidney with probenecid pretreatment were 2.30 ± 0.17 min and 17.03 ± 2.47 min, respectively. T_1/2 of ^99mTc tricarbonyl cysteine in kidney with probenecid pretreatment were significantly different from that of untreated ones (4.30 ± 0.79 min) (p<0.0001). In conclusion, ^99mTc tricarbonyl cysteine is very simple to prepared and is rapidly excreted through urinary pathway by tubular secretion. (Author)

[en] The main goal of this study was to optimize the radioimmunoconjugation of monoclonal antivascular endothelial growth factor receptor 1(VEGFR 1) anti-CD105(Endoglin) monoclonal antibody for an angiogenesis targeting and with ¹⁷⁷Lu as a potential angiogenic molecular tracer for radioimmunotherapy (RIT). We carried out a radioimmunoconjugation using ¹⁷⁷Lu with anti-CD105 (Endoglin) and anti-VEGFR1 for developing a more useful marker to identify proliferating endothelium involved in tumor angiogenesis than panendothelial markers. We optimized the labeling of monoclonal antibody with ¹⁷⁷Lu by using cysteine derivative isothiocyanatobenzyl-DTPA(DTPA-NCS) as BFCA. Under the optimal conditions with a slight modifications on the factors such as the reaction time and molar ratio which are known to be very critical in radiolabeling. The labeling yield was greater than 99% each respectively. Immunoactivity of the radioimmunoconjugate was investigated using combinations of radioanalytical and bioanalytical techniques (ITLC- SG,Cyclone phosphorimager, SDS-PAGE and ELISA). For the biological evaluations we carried out a cell binding assay and a biodistribution study using mice bearing Calu 6 lung cancer cell xenografts. The tumor-to-blood ratio was 11.16:1 24h post-injection. For anti- VEGFR1 monoclonal antibody, the biodistribution study showed high specificity in accumulating in tumour tissues where the tumor-to-blood ratio was 3.25:1 24h post-injection. In conclusion, the anti-CD105 monoclonal antibody for an angiogenesis targeting was effectively radioconjugated with ¹⁷⁷Lu. And the biodistribution study showed a high specificity for accumulating in tumour tissues. This radioimmunoconjugate is applicable to detect angiogenesis sites in various diseases and to treat tumors. the anti-VEGFR1 monoclonal antibody for angiogenesis targeting was effectively radioconjugated with ¹⁷⁷Lu. This radioimmunoconjugate is applicable to detect of angiogenesis sites in various diseases and treat tumour over expressed VEGFR 1. (author)