Post-Effects of Radioactive Decay in DOTA Chelator and Magnetite Nanoparticles Labelled with Auger- and Internal Conversion Electron-Emitters, Alpha- and Beta Decay Radionuclides

Oct 13, 2020, 4:35 PM
25m
Online

Online

Oral report Section 8. Nuclear medicine. Section 8. Nuclear medicine

Speaker

Igor Alekseev (V.G. Khlopin Radium Institute)

Description

As it has been demonstrated by the conducted experiments, the production of targeted radioactive pharmaceutical preparations (RPHs) that are based on alpha-emitters using the traditional approach (biologically active molecular constructs with a chelate, DOTA, that carries a radioactive tracer) is just a sort of scientific mystification: the recoil nuclei formed after such decay will destroy the carrier molecules thus completely excluding a targeted transport of the preparation.
A success in the production of such pharmaceutical formulations that are based on the use of alpha-emitters is possible only in the case when there is some way of “levelling” the harmful effect of recoiling nuclei, for example, by means of using inorganic compounds (“nano-containers”) of a high radiation resistance.
As such a model matrix material, magnetite, Fe3O4, has been used whose main transport characteristic that accounts for the transportation accuracy of magnetite-based RPHs is the value of the internal magnetic field on the iron nuclei. The magnetite nano-crystallites have been prepared labelled with Auger- and internal conversion electrons, beta- and alpha-emitters (57Co, 60Co and 241Am radionuclides).
A comparative analysis has been conducted of radiation-induced damage patterns in nano-crystallites in the dependence of nuclear- and physical characteristics of the radioactive tracer and total fluence. It has been established that under irradiation there is a comminution of crystallites taking place, the effective magnetic fields on the iron atoms in the labelled nano-crystallites remaining unchanged irrespective of the “dose load”.
Taking into consideration the typical recoil energies (90 keV to 150 keV) of the daughter atoms that are produced as a result of alpha-decay, the chemical composition and density of possible “carriers” needed for an efficient “conservation” of traditional therapeutic radionuclides (in particular, 211At, 212Bi, 213Bi, and 223Ra), “nano-containers” should be used with the particle size of not less than 80 nm.
The work was supported by a grant from the Russian Foundation for Basic Research (18-03-00832).

Primary authors

Igor Alekseev (V.G. Khlopin Radium Institute) Dr Aleksandr Miroslavov (V.G. Khlopin Radium Institute)

Presentation materials