Effective half-life

Effective half-life denotes the halving of radioactive material in a living organism by means of radioactive decay and biological excretion. A decay constant is needed to calculate the half-life. It is the sum of the biological and physical decay constants, as in the formula:

:$\{lambda\_e\}\; ,\; =\; \{lambda\_p\}\; ,\; +\; \{lambda\_b\}\; ,$

With the decay constant it is possible to calculate the effective half-life using the formula:

:$t\_\{1/2\}\; =\; frac\{ln\; (2)\}\{lambda\_e\}$

The biological decay constant is often approximated as it is more difficult to accurately determine than the physical decay constant.

External links

* [http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/biohalf.html Biological Half-life]