16.1 Introduction
Radionanomedicine is anticipated to expedite the clinical translation of
nanomedicines, because it has the potential to address critical issues, such as
possible toxicity and lesser-known pharmacokinetic characteristics of nanomaterials
(or nanoparticles) by leveraging very low doses of radiolabeled nanomaterials
(radionanomaterials) instead. Radiolabeling of a nanomaterial enables the visualization of its distribution in living bodies up to great depths using nuclear medicine
imaging modalities, such as the positron emission tomography (PET) and single
photon emission computed tomography (SPECT). Even if a very small amount of
radiolabeled material (known as a radiotracer) is administered, its in vivo spatiotemporal biodistribution can be quantitatively measured by the above-mentioned
modalities owing to their high molecular sensitivity. Consequently, through tracer
kinetic analyses, one can obtain quantitative information regarding the underlying
physiological and biochemical processes associated with radiotracers by making
use of such spatiotemporal data [1, 2]. As such, radionanomedicine practices based
on the use of these techniques can not only avoid the use of high pharmacological
amounts of nanomaterials but can also provide relevant preliminary information
regarding the fate of nanomaterials, such as a rapid clearance from the body.
Tracer kinetic analyses could play a vital role in the success of radionanomedicines as it facilitates the development of clinically applicable nanomaterials by providing quantitative pharmacokinetic information. In fact, tracer kinetic
analysis is now attracting considerable interest from several emerging disciplines,
such as PET microdosing and precision medicine, because of the increased
importance of obtaining quantitative information for new drug development.
Tracer kinetic analysis of radiotracers based on their spatiotemporal distribution
enables quantitative measurement of the rate constants associated with various
physiological and biochemical processes. A tracer-kinetic model is a mathematical
description of the movement of radiotracers within a living biological system. In
most cases, the radiotracer movement is tracked from the arterial plasma to target
tissues. The rate of radiotracer movement (or a change in radiotracer concentration)
often provides direct information on the rate of a biological process. Therefore, one
can trace and understand dynamic physiological and biological processes through
tracer kinetic analysis [3–5].
The following describes a typical procedure followed in tracer kinetic analysis
providing quantitative measurement.
– Define the physiological and biochemical parameters to be determined.
– Introduce a tracer that follows the physiology of the mother substance without
disturbing the system.
– Record the time profiles of tracer concentrations in the blood and tissues.
– Apply a suitable mathematical model.
– Estimate the parameters of interest.
294
J. S. Lee et al.
Radionanomedicine is anticipated to expedite the clinical translation of
nanomedicines, because it has the potential to address critical issues, such as
possible toxicity and lesser-known pharmacokinetic characteristics of nanomaterials
(or nanoparticles) by leveraging very low doses of radiolabeled nanomaterials
(radionanomaterials) instead. Radiolabeling of a nanomaterial enables the visualization of its distribution in living bodies up to great depths using nuclear medicine
imaging modalities, such as the positron emission tomography (PET) and single
photon emission computed tomography (SPECT). Even if a very small amount of
radiolabeled material (known as a radiotracer) is administered, its in vivo spatiotemporal biodistribution can be quantitatively measured by the above-mentioned
modalities owing to their high molecular sensitivity. Consequently, through tracer
kinetic analyses, one can obtain quantitative information regarding the underlying
physiological and biochemical processes associated with radiotracers by making
use of such spatiotemporal data [1, 2]. As such, radionanomedicine practices based
on the use of these techniques can not only avoid the use of high pharmacological
amounts of nanomaterials but can also provide relevant preliminary information
regarding the fate of nanomaterials, such as a rapid clearance from the body.
Tracer kinetic analyses could play a vital role in the success of radionanomedicines as it facilitates the development of clinically applicable nanomaterials by providing quantitative pharmacokinetic information. In fact, tracer kinetic
analysis is now attracting considerable interest from several emerging disciplines,
such as PET microdosing and precision medicine, because of the increased
importance of obtaining quantitative information for new drug development.
Tracer kinetic analysis of radiotracers based on their spatiotemporal distribution
enables quantitative measurement of the rate constants associated with various
physiological and biochemical processes. A tracer-kinetic model is a mathematical
description of the movement of radiotracers within a living biological system. In
most cases, the radiotracer movement is tracked from the arterial plasma to target
tissues. The rate of radiotracer movement (or a change in radiotracer concentration)
often provides direct information on the rate of a biological process. Therefore, one
can trace and understand dynamic physiological and biological processes through
tracer kinetic analysis [3–5].
The following describes a typical procedure followed in tracer kinetic analysis
providing quantitative measurement.
– Define the physiological and biochemical parameters to be determined.
– Introduce a tracer that follows the physiology of the mother substance without
disturbing the system.
– Record the time profiles of tracer concentrations in the blood and tissues.
– Apply a suitable mathematical model.
– Estimate the parameters of interest.
294
J. S. Lee et al.