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Why are short half-lives useful for radioactive isotopes used in medical imaging?

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

In medical imaging, radioactive isotopes with short half-lives are highly advantageous because they decay rapidly, often disappearing completely before their emitted radiation can cause significant damage to a patient's healthy tissue.12

By utilizing isotopes that dissipate their energy quickly, clinicians can perform diagnostic procedures—such as positron emission tomography (PET) or single photon emission computed tomography (SPECT)—while minimizing the duration of a patient's exposure to potentially harmful ionizing radiation. This rapid decay ensures that the radioactive material does not remain in the body longer than necessary, which is a critical ethical consideration in prioritizing patient safety and minimizing unnecessary toxic exposure during medical care.123