METHOD FOR DETERMINING ACCUMULATED ABSORBED DOSES FROM β-RADIATION OF RADIOPHARMACEUTICAL IN ORGANS AND TISSUES OF LABORATORY ANIMALS Russian patent published in 2024 - IPC A61B5/00 G01T1/161 

FIELD: medicine.

SUBSTANCE: invention relates to experimental radiotherapy and can be used to determine accumulated absorbed doses from β-radiation of the radiopharmaceutical in organs and tissues of laboratory animals. Organs and tissues in which it is necessary to determine the absorbed doses are preliminarily modelled with the following chambers: blood plasma chamber, knee chamber, hip chamber, rib chamber, cranial chamber, spinal chamber, kidney chamber, thyroid chamber, lung chamber, heart chamber, spleen chamber, stomach chamber, intestinal chamber, thigh muscle chamber. Then activity is measured A_N^exp(t) simultaneously in all N model chambers on each of four animals for time t not less than 48 hours. At that, values of absorbed doses D_N(t_i) accumulated by time t_i in each of N model chambers are determined from solution of system of differential equations

and transport constants are based on the condition of minimum residual functional

.

If the experimental accuracy of measuring activity is ΔA_N^exp(t)/A_N^exp(t) in some of the given N chambers is less than the accuracy of simulating the absorbed dose ΔD_S(t)/D(t) in them, data of S chambers, except for blood chamber, are excluded from repeated measurements of activity. Thereafter, K-repeated experimental measurements of activity A_NS^exp(t) in all NS model chambers of organs and tissues on the second and next K group of laboratory animals. At the same time repeated solution of system of differential equations is carried out for calculation of specified transport constants. Experiment and simulation are repeated K times until the accuracy of determining the value of the absorbed dose in organs and tissues is higher and equal to the accuracy of measuring activity in them.

EFFECT: method provides higher accuracy and reliability of measuring absorbed doses in given organs and tissues for determining the suitability of radiopharmaceuticals for treating said organs and tissues as intended by repeating the experiment and modelling K times until the accuracy of determining the value of the absorbed dose in organs and tissues is higher and equal to the accuracy of measuring activity in them.

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