Mathematical modeling the kinetics and calculation of dosimetric characteristics of osteotropic radiopharmaceutical drugs

In Russian medicine two radiopharmaceuticals are currently used for radionuclide therapy of bone metastases: $^{89}$Sr-chloride and $^{153}$Sm-oxabifor. The first one has many side effects, so its use is limited. The second one is available only in clinics, its transportation to which does not take much time. Currently, the third radiopharmaceutical $^{188}$Re-solerene is undergoing clinical trials. Due to the generator method of obtaining $^{188}$Re, this radiopharmaceutical should become available for use in many regions of our country. Therefore, there is a need for a comparative analysis of the characteristics of these radiopharmaceuticals, including on the basis of mathematical modeling.
The article discusses the features of mathematical modeling the kinetics of osteotropic radiopharmaceutical drugs in the human body with bone metastases. Based on the four-compartment model, a complex of modeling and calculation of pharmacokinetic and dosimetric characteristics of radiopharmaceuticals for radionuclidetherapy of bone metastases was developed and tested. Using clinical data, the transport constants of the model were identified and the individual characteristics of Russian radiopharmaceuticals labeled $^{89}$Sr, $^{153}$Sm and $^{188}$Re were calculated (effective half-lives, maximum activity in the compartments and the times of their achievement, absorbed doses to bone tissue and metastases, endosteal bone layer, red bone marrow, blood, kidneys and bladder). The time activity dependencies for all compartments of the model are obtained and analyzed. A comparative analysis of the pharmacokinetics and dosimetry of three radiopharmaceuticals ($^{89}$Sr-chloride, $^{153}$Sm-oxabiphore, $^{188}$Re-solerene) was carried out.
From a comparative analysis of the pharmacokinetic and dosimetric characteristics of these radiopharmaceutical drugs, it follows that the best of them for wide spread use in many regions of our country should be $^{188}$Re-solerene, taking into account the generator method of obtaining $^{188}$Re in a hospital.