Conventional radiocarbon dating
Once produced, it mixes rapidly across each of the hemispheres, quickly entering the terrestrial food chain through photosynthesis, with the result that the C is an unstable (radioactive) isotope, with a half-life of 5730±40 years, the proportion of radiocarbon in the deceased organism decreases over time. It is by measuring the amount of radiocarbon that remains that scientists are able to estimate the amount of time that has passed since the organism’s death. (0.03 vol %), it becomes part of the carbon cycle in the biosphere.Assimilated by plants, it enters the food chain and thus becomes part of all living organic matter.
The bone-powder is treated with 8% HCl, finally the sample is washed to p H=3 and the collagen extracted by hot water at 90 C during 24 hours at p H=3 by the same procedure as suggested by Longin.So even we humans are radioactive because of trace amounts of radiocarbon in our bodies.