Biological half-life

The time required for the radioactivity of a radioactive substance taken into the body to be reduced to half through physiological excretion processes. The radioactivity of a radioactive substance in the body appears to decrease through both physiological excretion processes and radioactive decay, and the time it takes for the radioactivity to be reduced to half through both of these processes is called the effective half-life. There is a relationship between the biological half-life T _b , the physical half-life T _p (the time it takes for the radioactivity to be reduced to half through radioactive decay), and the effective half-life T , as follows:

There is a relationship between

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

生理的な排出過程によって，生体内に取り込まれた放射性物質の放射能が，半分になるのに要する時間．生体内の放射性物質の放射能は見掛け上，生理的排出過程と放射性崩壊の両方によって減少していくが，この両方によって放射能が半分になるまでの時間を実効半減期という．生物学的半減期 T_b，物理学的半減期 T_p(放射性崩壊によって放射能が半分になるのに要する時間)と実効半減期Tの間には，

の関係がある．

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