Preparation of (90)YCl(3) radiopharmaceutical precursor for nuclear medicine using technology of centrifugal extractors.

Separation of (90)Y from a parent solution of (90)Sr-(90)Y in 0.5 M nitric acid by two-stage liquid-liquid extraction has been investigated using centrifugal extractors. The extraction agent used was 0.25 M di-(2-ethylhexyl)phosphoric acid (D2EHPA) in n-dodecane. Back-extraction used 5 M HCl. Evaporation of HCl was performed in a rotary vacuum evaporator. Experience gained during the design, construction and running of more than 100 hot separations is presented. A short description of analytical methods used and results of the determination of chemical, radionuclidic and radiochemical purities and sterility are given.

Standard test of labelling for efficiency for quality control of no carrier added 90YCL3 / Prueba estándar de la eficiencia del marcaje para el control de la calidad del 90YCI3 sin portador añadido

ABSTRACT Particle emitting radionuclides (e.g. b--emitters 90Y and 177Lu, b-emitter 149Tb, Auger electron emitter 165Er or positron emitter 86Y) are more and more frequently used in research and clinical practice for imaging and radionuclide targeted therapy in nuclear medicine. These radiometals, altogether threevalent lanthanides or actinides with high specific radioactivity, coupled to biomolecule carriers (peptides or monoclonal antibodies) through chelating link (e.g. DTPA or DOTA) bind to specific antigens and/or receptors of diseased tissues, which enables the imaging (positron emitters) or destruction (b--, a-, and Auger electron emitter) of the diseased tissue releasing the antigens or carrying the receptors. The radionuclide precursor 90YCl3 (solution of hard b--emitter 90Y in diluted HCl) with high purity and specific activity is already commercially produced and succesfully used in nuclear medicine, e.g. for radioimmunotherapy (RIT) of Lymphoma. Specification and purity of our product obtained using extraction 90Sr/90Y generator (using technology of centrifuge extractors with di-2-ethylhexylphosphoric acid, D2EHPA) is examined and compared to other similar products in this contribution. A standard method for determination of labelling efficiency of the 90YCl3 precursor based on its reaction with DOTA-Tyr3-Octreotide (DOTA-TOC) and ITLC-SG chromatographic separation is described and proposed for the quality control.

Los radionucleidos emisores de partículas (ej. emisores b 90Y y 177Lu, emisores a 149Tb, emisor de electrones Auger 165Er o emisor de positrones 86Y) se emplean cada vez más en la investigación, en la práctica clínica para el procesamiento de imágenes y en la terapia dirigida de radionuclidos en medicina nuclear. Estos radiometales junto con actínidos o lantánidos trivalentes con alta actividad específica, asociados a portadores de biomoléculas (péptidos o anticuerpos monoclonales) por medio de un enlace con quelatos (ej. DTPA o DOTA) se unen a antígenos específicos receptores de tejidos afectados que permiten el procesamiento de imágenes (emisores de positrones) o la destrucción (b--, a-, y emisores de electrones de Auger) de los tejidos afectados que liberan los antígenos o portan los receptores. El precursor del radionucleido 90YCI3 (solución de emisor b- duro - 90Y en HCI diluido) con elevada pureza y actividad específica ya se produce comercialmente y se usa exitosamente en la medicina nuclear, por ejemplo, para la radioinmunoterapia (RIT) del linfoma. En esta contribución se examina la especificación y la pureza de nuestro producto, obtenido mediante extracción con generador 90Sr/90Y (empleando la tecnología de extractores por centrifugado con ácido di-2-ethylhexyl phosphoric D2EHPA) y se compara con otros productos similares. Se describe y propone para el control de la calidad un método estándar para determinar la eficiencia en el marcaje del precursor del 90YCI3 basado en su reacción con DOTA-Tyr3-ostreotido (DOTA-TOC) y separación cromatográfica ITLC-SG.

Preparation and quality control of [166Ho]-macroaggregates for radiosynoviorthesis.

(166)Ho is a beta-emitter (E(_max) = 1.84 MeV, T1/2 = 26.7 hours) with a mean penetration in the soft tissue of 2.2 mm and gamma-photons 81keV and 1380keV. In this paper, we present our experiences with preparation of (166)Ho-macroaggregates ((166)Ho-MA) for radiosynoviorhesis. Ho-MA were prepared by reacting the aqueous solution of holmium nitrate pentahydrate with sodium borohydride solution in 0.2 M NaOH. After centrifugation, washing, and drying at 105 degrees C, final fineness of 1-15 microm was attained using a homogenizer working at 70,000 rpm. Neutron activation was carried out in screwed titanium ampules in a nuclear reactor at the neutron flux 10E12-10E14 neutrons.cm-24.s-1. The irradiated samples were allowed to cool 24 hours before further manipulation. (166)Ho-MA were clinically tested on 20 patients suffering from gonarthrosis (15), rheumatoid arthritis (5), psoriatic arthritis (1), and gout arthropathy (1). (166)Ho-MA are currently produced under GMP and production facility allows producing radioactivity for 6 patients within one production run.

Our first clinical experience with radiosynoviorthesis by means of (166)Ho-holmium-boro-macroaggregates.

BACKGROUND: In this paper, we evaluate the therapeutic and adverse effects of the application of 166-holmium-boro-macroaggregates (HMBA) in radiosynovectomy (RSO) of the knees. We assessed the efficacy and safety of (166)Ho-HBMA in a prospective clinical trial in patients suffering from chronic synovitis. MATERIAL AND METHODS: An effective component of radiopharmaceutical (166)Ho-boro-macroaggregates is radionuclide (166)Ho which has both beta-emission and gamma-emission. The physical half-life time of 166 Ho is 26.8 hours. After application of the radiopharmaceutical into a joint cavity, the effect of beta-emission causes radiation necrosis of pathologically changed (inflamed) synovial membrane. From 15th April 2005, we have started RSO of knees by means of new radiopharmaceutical (166)Ho-boro-macroaggregates in patients with gonarthrosis, rheumatoid arthritis, chronic synovitis, psoriatic arthritis, gout arthropathy. Seventeen intra-articular injections were performed in fifteen patients receiving a mean activity of 972 MBq (range: 904-1,057 MBq) (166)Ho-HMBA. The patients were hospitalized for three days. Side effects were evaluated during hospital stay and after 6-8 weeks. Static scintigraphy of knee joints and measurements of blood radioactivity were performed. Therapeutic effects were evaluated after 6-8 weeks. RESULTS: In 2 hours and 2 days after application, we proved, by means of knee and inguinal scintigraphy, only insignificant radiopharmaceutical leakage from the joint cavity to the inguinal lymph nodes in four patients. In treated patients, no serious adverse effects occurred. Nine patients were without complaints; 4 patients had slight knee exsudation and 2 patients had great exsudation. Therapeutic effects after 6-8 weeks were as follows: 2 patients were without pain, 9 with lower pain, 3 with the same pain and 1 patient with increased pain. Joint motion was improved in 7 patients, remained the same in 7 patients and was impaired in 1 patient. Analgesics consumption was lower in 5 patients, the same in 9 patients and greater in 1 patient. Knee exsudation was absent in 2 patients, lower in 4 patients, the same in 6 patients and greater in 3 patients. CONCLUSIONS: We proved only insignificant radiopharmaceutical leakage from the joint cavity to the inguinal lymph nodes. Six patients had early slight or great radiation synovitis. The possible cause could be rather high applicated activity. One can take into consideration its reduction. Therapeutic effects can be precisely evaluated after a longer time interval than was possible for us (6-8 weeks after RSO). (166)Ho-boro-macroaggregates can extend the scale of clinically used radiopharmaceuticals for RSO. This paper is presented in the scope of the first stage of clinical evaluation of synovectomy application of holmium-boro-macroaggregates.

18F-fluorodeoxyglucose accumulation in the heart, brain and skeletal muscle of rats; the influence of time after injection, depressed lipid metabolism and glucose-insulin.

BACKGROUND: To study the effect of lipid depressing drugs on (18)FDG myocardial concentration. The changes of (18)FDG uptake in myocardium, brain and skeletal muscle of rats were compared as influenced by acipimox, tyloxapol and glucose with insulin. MATERIAL AND METHODS: 5.55 MBq of (18)FDG were administered to Wistar rats. Control rats were killed 15, 30, 45 and 60 minutes following intravenous injection and the radioactivity concentration (cpm/g of tissue) in relation to injected cpm was determined in a well crystal adjusted to 511 KeV in order to check the time of maximal (18)FDG tissue uptake. The radioactivity in myocardium, skeletal muscle and brain in intact animals was compared with that of rats treated with tyloxapol (tritton WR 1339, 125 mg intravenously immediately before (18)FDG injection), acipimox (nicotinic acid derivative, 25 mg by stomach cannula 15 minutes before (18)FDG), or glucose with insulin (intravenous injection of 0.04 g and 0.04 UI immediately before (18)FDG). The animals were killed 45 minutes following (18)FDG injection. RESULTS: Tyloxapol and acipimox significantly elevated myocardial (18)FDG concentration (tyloxapol +37% and acipimox +48%), but the increase in (18)FDG concentration after glucose and insulin was slight and insignificant. The changes in skeletal muscle after lipid depressing agents were quite contrasting; the decrease in (18)FDG concentration was -74% after tyloxapol and -44% following acipimox administration. The accumulation of (18)FDG in brain was not influenced markedly by the drugs used or by glucose with insulin. CONCLUSION: The highest (18)FDG uptake in myocardium could be achieved by depressing the lipid metabolism and not by administration of glucose with insulin only. A marked increase in glucose accumulation in myocardium is not possible without previous shift from the utilisation of fatty acids. This finding is fully in agreement with present knowledge about energetic metabolism of myocardium.

Intrasellar carotid anastomosis simulating pituitary microadenoma.

Arterial communication between the cavernous segments of the carotid arteries associated with agenesis of the unilateral internal carotid artery is a rare anomaly. Two cases of this anomalous artery with an abnormal sella turcica due to the intrasellar course are reported.

Application of a new torque wire in visceral, extremity, and neuroangiography.

The authors describe a flexible torque wire which is beneficial in superselective catheterization. Used in conjunction with the 5 French catheter, it permits high quality results in tortuous aortic arches and there have been no complications.