A quantitative evaluation of multiple biokinetic models using an assembled water phantom: A feasibility study

Abstract

This study examined the feasibility of quantitatively evaluating multiple biokinetic models and established the validity of the different compartment models using an assembled water phantom. Most commercialized phantoms are made to survey the imaging system since this is essential to increase the diagnostic accuracy for quality assurance. In contrast, few customized phantoms are specifically made to represent multi-compartment biokinetic models. This is because the complicated calculations as defined to solve the biokinetic models and the time-consuming verifications of the obtained solutions are impeded greatly the progress over the past decade. Nevertheless, in this work, five biokinetic models were separately defined by five groups of simultaneous differential equations to obtain the time-dependent radioactive concentration changes inside the water phantom. The water phantom was assembled by seven acrylic boxes in four different sizes, and the boxes were linked to varying combinations of hoses to signify the multiple biokinetic models from the biomedical perspective. The boxes that were connected by hoses were then regarded as a closed water loop with only one infusion and drain. 129.1±24.2 MBq of Tc-99m labeled methylene diphosphonate (MDP) solution was thoroughly infused into the water boxes before gamma scanning; then the water was replaced with de-ionized water to simulate the biological removal rate among the boxes. The water was driven by an automatic infusion pump at 6.7 c.c./min, while the biological half-life of the four different-sized boxes (64, 144, 252, and 612 c.c.) was 4.8, 10.7, 18.8, and 45.5 min, respectively. The five models of derived time-dependent concentrations for the boxes were estimated either by a self-developed program run in MATLAB or by scanning via a gamma camera facility. Either agreement or disagreement between the practical scanning and the theoretical prediction in five models was thoroughly discussed. The derived biokinetic model represented the metabolic mechanism in the human body and helped to solidify the internal circulatory system into concert with numerical verification.

Quantitative Prediction of SYNTAX Score for Cardiovascular Artery Disease Patients via the Inverse Problem Algorithm Technique as Artificial Intelligence Assessment in Diagnostics

“…Specifically, the defined agreement (AT) equals [(actual − prediction)/actual] of the SYNTAX score. Therefore, the average AT avg and standard deviation of the 105 ATs are 0.308 and 0.193, respectively, implying high agreement between the actual and predicted values of the SYNTAX score [ 12 , 13 , 14 ]. Figure 6 illustrates the distribution of 105 individual ATs in this study.…”

Biokinetic model of radioiodine I-131 in nine thyroid cancer patients subjected to in-vivo gamma camera scanning: A simplified five-compartmental model

“…Further, all the empirical data after normalization were assigned as the ideal objective expectation of dataset for optimization of the program prediction to obtain the parameter. An agreement value (AT) earlier adopted by the authors in [5,7,12] was used to determine the similarity between the empirical data and respective optimal predictions made via the self-developed program run in MATLAB. This AT-based approach, which was an extension from the definition of conventional RMS (root mean square) method, was beneficial in evaluating the fluctuation among large datasets because a quantified AT value was focused not only on the difference between particular empirical and theoretical results but also on the integration of all data in the same group.…”

“…Thus, in the field of precision machining, a derived RMS was used to assess the surface roughness of large-area workpieces [13]. The agreement value AT was defined in [5,7,12] as follows:…”