Whole body counter
ORTEC
If gamma emitters are located inside the human body, and if the energy of the gamma rays is high enough that they can escape the body before being absorbed or have any other interaction where it can lose energy, they can be detected and identified. Usually either a scintillation detector or a semiconductor detector would be used for such purposes.
There are many ways a person can be positioned for this measurement: sitting, lying, standing. The detectors can be single or multiple and can either be stationary or moving.
The advantages of Whole-Body Counting are that it measures body contents directly and does not rely on indirect methods (such as urinalysis) and that it can measure insoluble radionuclides in the lungs.
On the other hand, disadvantages of Whole-Body Counting are that it can only be used for gamma emitters, except in special circumstances, and it is possible to misinterpret external contamination as an internal contamination.
A Whole-Body Counter is calibrated with a device known as a Phantom containing a known distribution and known activity of radioactive material. A Phantom typically consists of a number of high density polyethylene containers into which the radioactive standards can be placed.
