Determination of chemical purity and specific activity of 177g,mLuCl3 by INAA and ET-AAS

Radioactive solutions of ^177g,mLu^IIICl₃ are used for labeling organic compounds for metabolic radiotherapy and radioimmunotherapy. The labeling process involves Lu in III oxidation state, so the presence of other stable impurities in the same oxidation state could result in an isomorphous dilution of radioactive ^177gLu. Samples of ^177gLuCl₃ were analyzed to quantify the chemical impurities with a special regard for trivalent elements with instrumental neutron activation analysis (INAA), carried out in the research nuclear reactor TRIGA MARK II (GA, USA) of the Università degli Studi di Pavia, and electrothermal atomic absorption spectroscopy (ET-AAS) (Varian, USA) at LASA.     

Accurate determination of half-life and radionuclidic purity of reactor produced <Superscript>177g</Superscript>Lu (<Superscript>177m</Superscript>Lu) for metabolic radiotherapy

Thanks to its favorable decay characteristics, ^177gLu is finding several applications in nuclear medicine, especially for palliative metabolic radiotherapy of cancer and radioimunotherapy. ^177gLu is produced in thermal nuclear reactor either by direct neutron capture ¹⁷⁶Lu(n,γ)^177(m+g)Lu on either natural or enriched ¹⁷⁶Lu target, or by reaction on enriched ¹⁷⁶Yb target followed by negatron decay. The latter method does produce a high radionuclidic purity and high specific activity radionuclide in no-carrier-added form, since ¹⁷⁷Yb decays solely to the ground state ^177gLu. Conversely, the first method does produce a low specific activity ^177gLu in carrier-added form,¹ contaminated by the long-lived radioisotopic impurity ^177mLu. The accurate determination of radionuclidic purity and half-life of ^177gLu carried out by HPGe and LSCS is presented in some details.     

Maintaining radiochemical purity of [177Lu]Lu-DOTA-PSMA-617 for PRRT by reducing radiolysis

Journal of Radioanalytical and Nuclear Chemistry - [177Lu]Lu-DOTA-PSMA-617 for PRRT is subject to radiolysis and therefore loses receptor affinity. This will be detrimental for treatment efficacy....     

Electrochemical method for producing radionuclide Lu-177 with high specific activity

A modified method for the isolation of radionuclide ¹⁷⁷Lu obtained from a Yb-176 target irradiated with thermal neutrons is proposed. The method consists of the combination of two electrochemical processes— cementation of ytterbium acetate–chloride solution to sodium amalgam and subsequent electrolysis of the ytterbium solution in a separate electrolytic cell without adjusting the solution. The electrochemical setup consisting of two cells gives the purification factor of ¹⁷⁷Lu from ytterbium at a level of 10⁵–10⁶, which allows using ¹⁷⁷Lu of such quality for labeling bioorganic molecules.     

Production of 177Lu by neutron activation of 176Lu

Production of the radiopharmaceutical nuclide ¹⁷⁷Lu, by direct thermal neutron activation of ¹⁷⁶Lu, poses a discrepancy between experimentally measured and theoretically predicted activities. It was found that in the irradiation at the pneumatic transfer tube (Rabbit) of the IRR-1 reactor, the exper./theor. ratio was 1.858± 0.051. This ratio was determined also by comparing the activities of ¹⁷⁷Lu and ^176mLu. The significant deviation of ¹⁷⁶Lu from the 1/v behavior explained this disagreement. The ratio exper./theor. is the Westcott g(T _n)-factor and was used to yield the neutron temperature T _n = 311±8 K.The assistance of Eyal Elish in performing the ICP-MS analyses of Lu is gratefully acknowledged.     

Production of 177Lu by neutron activation of 176Lu

Production of the radiopharmaceutical nuclide ¹⁷⁷Lu, by direct thermal neutron activation of ¹⁷⁶Lu, poses a discrepancy between experimentally measured and theoretically predicted activities. It was found that in the irradiation at the pneumatic transfer tube (Rabbit) of the IRR-1 reactor, the exper./theor. ratio was 1.858± 0.051. This ratio was determined also by comparing the activities of ¹⁷⁷Lu and ^176mLu. The significant deviation of ¹⁷⁶Lu from the 1/v behavior explained this disagreement. The ratio exper./theor. is the Westcott g(T _n)-factor and was used to yield the neutron temperature T _n = 311±8 K.The assistance of Eyal Elish in performing the ICP-MS analyses of Lu is gratefully acknowledged.     

Estimation of 47Sc and 177Lu production rates from their natural targets in Kyoto University Research Reactor

Journal of Radioanalytical and Nuclear Chemistry - To assess the capability of Kyoto University Research Reactor to supply the domestic needs of medical isotopes, its neutron flux has been fully...     

Investigation of chloride sensitive ISFETs with different membrane compositions suitable for medical applications

Cl⁻-ion sensitive ISFETs with photocured polyurethane-based polymer membranes with six different ionophores (ETH 9033, ETH 9009, MnTPPCl, organotin compounds and traditional ion-exchanger TDMACl) have been studied in pure NaCl solutions and in background solutions containing anions in concentrations normally found in a whole blood and serum. PVC or silicon resin were used to form the membranes in cases when it was not possible to use the photocurable polymer composition. Experimental results on determination of chloride ions in serum samples are presented. Performed tests showed that all chloride-selective ionophores commercially proposed up to now, both neutral and charged carriers, do not provide better selectivity and stability of chloride ion sensors for clinical application than the traditional anionic ion-exchanger TDMACl.     

Alternative chromatographic processes for no-carrier added 177Lu radioisotope separation

HPLC technique combined with the simple conventional column solid phase extraction (SPE) chromatography using di-(2-ethylhexyl)orthophosphoric acid (HDEHP) impregnated OASIS-HLB sorbent based SPE resins (OASIS-HDEHP) was developed for the separation of no-carrier added (n.c.a) ¹⁷⁷Lu from the bulk quantity of ytterbium target. This combination strategy was based on combining the advantages of the better resolution of HPLC separation of n.c.a ¹⁷⁷Lu from the few milligram level Yb target with the high capacity of the OASISHDEHP column for the separation of ¹⁷⁷Lu from the bulk Yb target. The production batches of several hundred mCi activity of n.c.a ¹⁷⁷Lu radioisotope separated from 50 mg Yb target activated in a nuclear reactor of medium neutron flux (Φ=5·10¹³ n·cm^?2·s^?1) were successfully performed using this combined separation technique. With the target irradiation in a reactor of higher thermal neutron flux or with the parallel run of several separation units, several Ci-s of n.c.a ¹⁷⁷Lu can be profitably produced on a commercial production basis.     

The synthesis of13N-labelled nitrite of high specific activity and purity

An improvement in a method for the synthesis of¹³NO ₂ ⁻ from¹³NO ₃ ⁻ with specific activity>30 mCi/mL and radiochemical purity>99% is described.¹³NO ₃ ⁻ is produced by the¹⁶O(p, α)¹³N reaction using a recirculating water target and 20 MeV protons.¹³NO ₂ ⁻ is synthesized by reduction of¹³NO ₃ ⁻ in a cadmium-copper column. Contaminating¹³NH ₄ ⁺ is removed by rotatory evaporation at pH>11.0. The synthetic procedure takes less than 20 minutes from collection of irradiated target water to sterilization of the radiopharmaceutical.     

Production of no-carrier-added 177Lu via the 176Yb(n, &;#947;)177Yb &;#8594; 177Lu process

No-carrier-added ¹⁷⁷Lu was produced by the ¹⁷⁶Yb(n,)¹⁷⁷Yb¹⁷⁷Lu process using enriched ¹⁷⁶Yb₂O₃. The radiochemical separation of the nca ¹⁷⁷Lu from the macroscopic ytterbium target was investigated by reversed-phase ion-pair HPLC. Effects of the concentrations of 2-hydroxyisobutyric acid and 1-octanesulfonate in the eluent, the amount of Yb₂O₃, the type and length of the C₁₈ column on the separation efficiency were examined. Under optimum conditions, the nca ¹⁷⁷Lu was obtained in radiochemically pure form from 5 mg of Yb₂O₃ with a separation yield of 84%.     

Recovery of 177Lu from Irradiated HfO2 Targets for Nuclear Medicine Purposes

A new method of production of one of the most widely used isotopes in nuclear medicine, ¹⁷⁷Lu, with high chemical purity was developed; this method includes irradiation of the HfO₂ target with bremsstrahlung photons. The irradiated target was dissolved in HF and then diluted and placed onto a column filled with LN resin. Quantitative sorption of ¹⁷⁷Lu could be observed during this process. The column later was rinsed with the mixture of 0.1 M HF and 1 M HNO₃ and then 2 M HNO₃ to remove impurities. Quantitative desorption of ¹⁷⁷Lu was achieved by using 6 M HNO₃. The developed method of ¹⁷⁷Lu production ensures high purification of this isotope from macroquantities of hafnium and zirconium and radioactive impurities of carrier-free yttrium. The content of ^177mLu in ¹⁷⁷Lu in photonuclear production was determined. Due to high chemical and radionuclide purity, ¹⁷⁷Lu obtained by the developed method can be used in nuclear medicine.     

Polymers for medical applications

The paper starts with some general introductory comments on properties and influence factors such as biocompatibility, surface structure, processibility and purity. Hence it is derived that polyurethanes deserve special attention as biomaterials, which is explained by the variability of the structure. A number of examples with new types of polyurethane elastomers are described, their advantages and disadvantages are pointed out, and conclusions are drawn for further research.     

Production of 177Lu by hafnium irradiation using 55-MeV bremsstrahlung photons

Journal of Radioanalytical and Nuclear Chemistry - The possibility of production a medical radionuclide 177Lu by irradiating natHfO2 by bremsstrahlung photons up to 55&nbsp;MeV was...     

89Zr and 177Lu labeling of anti-DR5 monoclonal antibody for colorectal cancer targeting PET-imaging and radiotherapy

Journal of Radioanalytical and Nuclear Chemistry - Death receptor 5 (DR5) is overexpressed in many tumors. Combination of the anti-DR5 antibody with radionuclides such as lutetium-177 (177Lu) could...     

ePTFE functionalization for medical applications

Polytetrafluoroethylene (PTFE) is a ubiquitous material used in implants and medical devices in general due to its high biocompatibility and inertness; blood vessels, heart, jawbone, nose, eyes, or abdominal wall can benefit from its properties in the case of disease or injury. Its expanded version, ePTFE, is an improved version of PTFE with better mechanical properties, which extend its medical applications. However, ePTFE implants often lack improvement in properties such as antibacterial, antistenosis, or tissue integration properties. Improvements in these properties by several strategies of functionalization for medical purposes are discussed in this review. Covalent and non-covalent bonding are reviewed, including more specifically chemical impregnation, chemical surface modification, autologous vascularization, and cell seeding, which are strategies mainly used for improving the properties of ePTFE and are described in this review.