Quantitative analysis of multiple biokinetic models using a dynamic water phantom: A feasibility study

Abstract

This study analyzed multiple biokinetic models using a dynamic water phantom. The phantom was custom-made with acrylic materials to model metabolic mechanisms in the human body. It had 4 spherical chambers of different sizes, connected by 8 ditches to form a complex and adjustable water loop. One infusion and drain pole connected the chambers to an auxiliary silicon-based hose, respectively. The radio-active compound solution (TC-99m-MDP labeled) formed a sealed and static water loop inside the phantom. As clean feed water was infused to replace the original solution, the system mimicked metabolic mechanisms for data acquisition. Five cases with different water loop settings were tested and analyzed, with case settings changed by controlling valve poles located in the ditches. The phantom could also be changed from model A to model B by transferring its vertical configuration. The phantom was surveyed with a clinical gamma camera to determine the time-dependent intensity of every chamber. The recorded counts per pixel in each chamber were analyzed and normalized to compare with theoretical estimations from the MATLAB program. Every preset case was represented by uniquely defined, time-dependent, simultaneous differential equations, and a corresponding MATLAB program optimized the solutions by comparing theoretical calculations and practical measurements. A dimensionless agreement (AT) index was recommended to evaluate the comparison in each case. ATs varied from 5.6 to 48.7 over the 5 cases, indicating that this work presented an acceptable feasibility study.

BIOKINETIC MODEL OF Tc-99m MIBI FOR EIGHT PATIENTS UNDERGONE MYOCARDIAL PERFUSION EXAMINATION via GAMMA CAMERA AND MATLAB PROGRAM: AN IN-VIVO STUDY

“…After the scanned data from the gamma camera were collected, converted to count/ pixel/sec, and normalized, the similarity between the optimal predictions calculated by MATLAB and the empirical data was analyzed via the agreement value (AT) approach earlier adopted by the authors 7,12 and described in detail elsewhere. 13,14 Briefly, this approach is revised from the root mean square (RMS) method in evaluating the significant number of acquired data.…”

“…5,6 Some dynamic water phantoms were also developed to simulate the biokinetic model under specific conditions. Chiang applied two identical acrylic blocks to assemble a water-proof phantom containing four independent chambers, which could be manually interconnected or disconnected, 7 whereas Yeh 8 assembled water phantoms using four kinds of water boxes with various combinations of linked pipes to customize any unique correlation among compartments. Both of the above research groups explored their biokinetic models by data processing via a MATLAB program.…”

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

“…Hsu et al [6] applied a similar technique to elaborate a biokinetic model of the gastrointestinal (GI) tract for 24 healthy volunteers. In contrast, Chiang et al [7] surveyed five biokinetic models with a dynamic water phantom and gamma camera technique. The methodology of compiling the gamma camera technique with various theoretical biokinetic models became more straightforward and user-friendly after coupling the state-of-the-art gamma cameras with computed tomography (CT).…”

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

“…However, few phantoms are made to imply the multi-compartment biokinetic models. This is because the cumbersome calculations required to solve the biokinetic models and the time-consuming verifications of the obtained solutions have significantly impeded the progress over the past decade [ 1 ]. A well-defined biokinetic model can assist the medical physicists in estimating internal dose or predicting the time-dependent quantity of radio-labeled complexes in crucial organs from the clinical viewpoint.…”

“…Sometimes a phantom is customized as an elliptical box with only one infusion and a drain hose; the dynamic metabolic mechanism is suggested by changing the amount of feed-water input [ 2 , 3 , 4 ]. As an alternative to this method, Chiang [ 1 ] proposed a unique water phantom to simulate five different biokinetic models by adjusting the water paths among the various water chambers. The adjustable path setting can be customized to fulfill a specific demand, although the limited combination of multiple path settings still has further applications.…”