carrieradded

Carrieradded refers to a property of radiochemical preparations in which non-radioactive, stable isotopes of the same element as the radionuclide are present in the final product. In such preparations, the radiotracer is accompanied by a stable "carrier" isotope, so the total amount of element is higher than the purely radioactive portion.

Carrieradded is often contrasted with no-carrier-added (NCA) radiochemistry, where the final product contains only the radioactive isotope with negligible stable isotope of the same element. The presence of the carrier reduces the specific activity, defined as activity per amount of substance, which can affect labeling efficiency, pharmacokinetics, and dosimetry in radiopharmaceutical applications.

Chemically, carrieradded radiotracers behave essentially the same as their noncarrier counterparts because the chemical species are identical; the main difference is the overall amount of the element present. The practical consequence is a lower radiochemical concentration and lower specific activity, which can influence purification requirements, target binding, and in some cases the feasibility of certain clinical applications.

Carrieradded production arises in various settings, including reactor or accelerator production where stable isotopes are present in the target material or subsequent separations leave residual stable isotopes. Understanding whether a radiopharmaceutical is carrieradded or no-carrier-added is important for quality control, labeling strategies, and regulatory considerations in nuclear medicine.