Mathematical Model of Respiratory Distortions of a Pathological Focus During Visualization on PET/CT Images

Abstract

The article presents an assessment and analysis of uncertainties in pathological lesion visualization on PET/CT images that arise due to respiratory movements of a biological object, which have a direct impact on determining the geometric characteristics of the pathological lesion, its localization, and the correctness of modeling the three-dimensional distribution of the radiation dose in the patient’s body. Based on the experimentally established dependencies of the influence of the displacement value and the diameter of the object (sphere) under study on the value of the discrepancy between the visualized volume of the object under study, a mathematical model of respiratory distortions of the pathological lesion during visualization on PET/CT images has been developed, which allows for a quantitative and qualitative assessment of the influence of the patient’s respiratory movement on the geometric accuracy of pathological lesion visualization on PET/CT images with up to 98 % accuracy. Verification of the model has shown a high degree of consistency between the model calculations and experimental data. The average values of relative uncertainty for CT and PET, respectively, were (2.123  1.051) % and (2.661  0.870) %, and for absolute uncertainty – (2.096  0.941) % and (1.992  0.782) %, which confirms the correctness and practical applicability of the developed method.