Obtaining radioactive isotopes for medical and technical purposes

Obtaining radioactive isotopes for medical and technical purposes at the INR RAS.

An underground laboratory with an installation for irradiating radioisotope targets with a proton beam from a high-current linear accelerator of hydrogen ions has been created and is successfully operating at the Institute of Nuclear Research of the Russian Academy of Sciences.

The installation is used to obtain radioisotopes for medical and technical purposes. Currently, it is one of the largest in the world in terms of energy accumulated for the production of isotopes. The installation has a high degree of automation and safety in operation. The central part of the installation is a target device located inside a protective cube.

The targets are mounted in a graphite holder at the end of the feed rod. A special feature of obtaining radioisotopes using medium-energy protons is that it is possible to simultaneously irradiate several different massive targets with a total thickness of several centimeters. In this design, the proton beam is directed at the target at an angle of 26°.

A special cooled graphite collimator, in which thermocouples are installed, allows you to quickly control the beam deviation from the axis, beam width and losses. The vacuum of the ion guide from the accelerator and the irradiation chamber with water cooling the target are separated by a telescopically inserted multilayer entrance window - a lithium metal plate is embedded between two stainless steel foils. This design dramatically increases the reliability and durability of this critical design element. Cooling and control systems allow achieving high operating parameters.

The installation is regularly used to produce a range of radioisotopes, mainly for medical purposes.

Radionuclides produced at INR RAS, and the possibilities of their production in one irradiation (at current 120 µA)

Produced regularly

Technology developed

Production methods have been developed, technology is under development

The most important isotope produced is strontium-82. Its half-life (25.5 days) allows the product to be transported over long distances, including abroad. For many years, there have been regular deliveries of accelerator-irradiated targets containing more than 1 curie of strontium-82 to Los Alamos National Laboratory (USA), where it was isolated radiochemically in “hot” chambers using INR RAS technology.

The isolated radionuclide is then sent for charging into generators of short-lived rubidium-82 (half-life 1.3 minutes), which is used for cardiac diagnostics using positron emission tomography (PET).

New original technologies for producing isotopes developed at the INR RAS are also used in France - the ARRONAX cyclotron medical complex (Nantes, France), the ZEVACOR company (Indiana, USA) and in other major centers.

The INR RAS has developed its own medical rubidium-82 generator, which is superior in basic characteristics to its American counterpart. The generator passed clinical trials in Russia for cardiology and neuro-oncology, a registration certificate was received for this medical product, and it was introduced into medical practice at the largest medical center of the Russian Research Center of Radiology and Surgical Technologies named after. A.M.Granova Ministry of Health of the Russian Federation (St. Petersburg).

In the future, it is expected that the generator will be widely used throughout Russia and abroad, which will allow PET diagnostics of cardiac and some oncological diseases to be raised to a new level, without the use in clinics of expensive cyclotrons that produce short-lived isotopes.

Rubidium-82 generator for PET diagnostics of cardiac and oncological diseases

82Sr(25.5 days)—>82Rb(1.3 min.)

The INR RAS produces many other radionuclides from various targets. Radiochemical isolation techniques have been developed, carried out in collaboration with a number of institutes in Russia and abroad.

One promising new project is the production of actinium-225 (half-life 10 days) from thorium metal irradiated with medium-energy protons. This alpha-emitting radionuclide and its short-lived decay product bismuth-213 (46 min) are promising for the treatment of various oncological diseases using radioimmune therapy. In one 10-day irradiation session at the linear accelerator of the INR RAS, it is possible to obtain actinium-225 in an amount of 1-2 curies, which is comparable to world production per year. INR RAS has developed a radiochemical technology for separating actinium-225 from irradiated thorium targets, which will soon be installed in “hot chambers” of other organizations. INR RAS is also developing new effective medical actinium-225/bismuth-213 generators for the treatment of various diseases.

At the Institute with the participation of Brookhaven National Laboratory (USA) and the State Scientific Center of the Russian Federation IPPE named after. A.I. Leypunsky also developed a new technology for producing the radionuclide tin-117m, which is promising for the diagnosis and at the same time therapy (theranostics) of a number of oncological and vascular diseases. Preparations based on tin-117m are undergoing clinical trials in the USA.

INR RAS has over 20 Russian and foreign patents in the field of radionuclide production. Already, more than 350,000 patients have received medical care with the help of isotopes produced at the INR RAS, and millions with the help of technologies developed here.

The installation also produces radioisotopes and conducts research to study fundamental issues of nuclear physics: the interaction of protons with nuclei, the study of high-spin isotopes. measurement of neutrino mass, search for dark matter, etc.