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Why can radioactive tracers follow the movement of substances through the body?

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radioactivity Figure 1: Radioactive decay of beryllium-7 to lithium-7 by electron capture (EC; see text).

Radioactive tracers are effective for monitoring physiological processes because they are chemically identical to the stable isotopes of the same element. This allows them to participate in the body's natural biological and chemical pathways just as the stable material would.12

Because these tracers are radioactive, they emit radiation that can be detected externally using specialized equipment, such as gamma-ray spectrometers, scintillation detectors, or imaging techniques like positron emission tomography (PET). By tracking the location and intensity of this emitted radiation, physicians can observe the distribution, movement, and accumulation of the substance within specific tissues or organs. This capability is fundamental to nuclear medicine, enabling the assessment of blood flow, organ function, and the identification of abnormal growths like malignant tumors.1234