|RE||Rapid exchange soft tissue|
|ME||Medium exchange soft tissue|
|SE||Slow exchange soft tissue|
|TS||Trabecular bone surface|
|CS||Cortical bone surface|
|ETV||Exchanging trabecular bone volume|
|ECV||Exchanging cortical bone volume|
|NTV||Non-exchanging trabecular bone volume|
|NCV||Non-Exchanging cortical bone volume|
A new model for calcium metabolism in humans has been developed by the International Commision on Radiological Protection (ICRP) for the purpose of determining the radiation dose to an individual from the ingestion, injection, or inhalation of radio-calcium.
Using this 12 compartment model of calcium metabolism, it is possible to simulate the injection and metabolism of a radioloabeled calcium injection. Below is an illustration of the distribution of calcium after injection over a 1000 day period. As can be seen in the animation below, the majority (>90%) of the calcium is eliminated from the body within the first few days. After the period of exchange with soft tissues the calcium remains in the skeleton for many years.
The applications of this model go beyond determining radiological dose to an individual. For example, diseases such as osteoporosis and cancer can alter calcium metabolism. Models such as the one shown here could be used for the diagnosis of the afformentioned diseases as well as determining treatment efficacy.