Virtual platform for computer simulation of radionuclide imaging in nuclear cardiology. Comparison with clinical data.

Background: In the field of radionuclide imaging, in vivo human clinical studies are limited due to radiation exposure and ethical concerns, so mathematical modeling and in silico computer simulations based on digital models are becoming increasingly important. In the English-language literature, this approach is called "Virtual clinical trials". Aims: The aim of this work is to develop software tools for simulation of radionuclide visualization of myocardial perfusion by SPECT/CT with 99mTc-MIBI and to perform studies aimed at improving the accuracy of SPECT. Materials and methods: A software package "Virtual platform for simulations of the SPECT/CT method in nuclear cardiology" was developed using digital patient models, a scanner and assessment of the state of the myocardium using digital images of the left ventricle (LV) in the form of a "polar map". Verification of the software package was performed by comparing with clinical data obtained at the National Medical Research Center of Cardiology (Moscow). Simulation computer tests were carried out, in which the accuracy of assessing the state of the myocardium was studied, depending on the approach to normalizing the "polar map" and corrective factors in the reconstruction algorithm. Results: The results of simulation tests showed that the assessment of LV myocardial perfusion significantly depends on the method of normalizing the "polar map" and taking into account corrective factors in the reconstruction algorithm. The most accurate estimates were obtained when calculating the normalization coefficient from the average value of activity in the normal zone of the myocardium. It is shown that the common approach to pixel normalization with maximum intensity can lead to errors. The results of "virtual" trials were fully consistent with clinical observations. Conclusions: The transition from relative normalized values of activity in the myocardium to absolute quantitative estimates will allow removing the existing limitations and uncertainties and is the main condition for improving the diagnostic accuracy of the SPECT/CT method in nuclear cardiology.