放射線を用いた薬物動態解析法の原理と応用

抄録

This paper explains the principles and applications of pharmacokinetic analysis techniques using radiation. It starts by describing radioimmunoassay (RIA), which utilizes radioactive isotopes to quantify substances with high sensitivity. The concept of a ”tracer”, an extremely tiny amount of substance that behaves identically to the target drug, is important for understanding pharmacokinetics. Compartment models, which describe the dynamics of drugs within the body by modeling transportation between compartments, enable quantitative analysis. After reviewing the history of radiopharmacokinetics, a general mathematical framework is described. The framework relates the concentration-time curves to the transfer rate constants between compartments. An analysis method called spectral analysis extracts pharmacokinetic parameters without assuming an explicit compartment model a priori. As an example application, the author’s group has applied spectral analysis for proton beam monitoring in proton therapy. By extracting the production profile of N-13, the position of the Bragg peak can be determined in three dimensions.