Author: Mingyang Han, Jia Jing, Chongming Li, Hui Lin, Zhenyu Xiong ๐จโ๐ฌ
Affiliation: School of Physics, Hefei University of Technology, Rutgers Cancer Institute of New Jersey ๐
Purpose: To enrich the teaching case library of Computational Physics course, one of the basic courses in undergraduates majoring in physics. It is an excellent application case of Medical Physics for Computational Physics teaching that solving numerically the pharmacokinetic model of radiopharmaceuticals in nuclear medicine for its multidisciplinary integration, programming exercises and analytical skill training.
Methods: The pharmacokinetic model of radiopharmaceuticals including stomach, small intestine, blood, thyroid gland and bladder was studied. The set of first-order partial differential equations linking the entire digestive system was regularization and solved by Runge-Kutta (R-K) method. RK is an important implicit or explicit iterative method used for solving nonlinear ordinary differential equations. The ode15s solver in Matlab was used to perform the R-K method for its stiff problem. The simple MIRD geometric phantom and the digital Zubal phantom were used to estimate the activity and dose variation.
Results: The thyroid absorption fraction significantly affects the activity of various organs, especially for thyroid gland and bladder. The higher absorption fraction will significantly increase thyroid activity, but decrease bladder activity. As to stomach, small intestine and blood, the influences are not obvious. The other R-K algorithms as ode45, ode23 and ode113 little affect the results.
Conclusion: A portable calculator for pharmacokinetic model of radiopharmaceuticals was built with friendly graphical user interface (GUI) as a case of multidisciplinary integration. It is also an excellent application of Computational Physics Methods in Medical Physics teaching.