In many medical applications, it is useful to be able to detect or trace the location of certain components of the body, from which information relating to the state or health of a patient may be derived.
One method includes the injection into the body of a tracer element whose position is able to be detected from outside of the body. The location and movement of the tracer element provides useful information.
In some applications, the tracer is a dye that colours the tissue of interest upon interrogation from an external source.
In some other applications the tracer element is a radioactive isotope whose presence may be detected by detection of the radiation emitted by the isotope. One example of such an isotope is fluorodeoxyglucose. In use, the isotope is injected into the patient, and allowed to concentrate into the tissues of interest as will be understood by the person skilled in the art. After an allowed period of time, the location of the tracer is detected, providing information on the tissue in which the tracer is concentrated.
Disadvantages with many of the existing techniques include the use of radioactive elements and/or the need for large and costly detection equipment.