Radiotracery

Radiotracery is a term used to describe the tracing and mapping of radiotracers within living organisms using nuclear imaging techniques. It encompasses the preparation of radiolabeled compounds, their introduction into a biological system, the acquisition of images, and the quantitative analysis of tracer distribution over time. While not universally standardized as a single discipline, radiotracery is often discussed in the context of molecular imaging, where functional information about physiology and biochemistry is obtained from radiotracer behavior.

Imaging modalities commonly involved are positron emission tomography (PET) and single-photon emission computed tomography (SPECT), frequently combined with anatomical imaging such as CT or MRI for precise localization. Ex vivo approaches, such as autoradiography, can also be included under radiotracery to study tissue sections with high spatial resolution. Data are typically analyzed to produce time-activity curves, parametric maps, and kinetic models (e.g., standardized uptake values, or SUV, and other compartment models) that reflect tracer kinetics and tissue properties.

Applications span oncology, neurology, cardiology, and pharmacology. In oncology, radiotracery informs tumor metabolism and receptor expression; in neurology, it can reveal glucose utilization, amyloid or tau deposition, and neurotransmitter system function; in cardiology, it assesses perfusion and viability. In research, it supports pharmacokinetics and drug distribution studies.

Limitations include ionizing radiation exposure, dependence on specialized radiochemistry facilities, partial-volume effects, and variability in tracer biology. Safety considerations, regulatory approvals, and dosimetry are integral to practice. The term is sometimes used interchangeably with broader radiotracer imaging or molecular imaging, depending on the context.