Nuclear Image Acquisition

This chapter is about the physical principles of a non-invazive diagnostics method that makest it possible to follow and image (in 1D, 2D or 3D) biochemical processes going on in different organs by the use of some radioactive material.

This modern imaging technique is called nuclear imaging, which is one of the most important application of radioisotopes in in-vivo medical practice. In contrast to other imaging modalities (X-ray, ultrasound etc.) this method yields an emission image, ie. a map of the spatial distribution of the radioisotope, which implies functional information.

It is a basic requirement that the radioisotopes used should be sufficiently organ-selective (eg. iodine), should have a minimum of beta radiation, and, in order to minimize patient dose, the half-life should be sufficiently short. In in-vivo applications the radioisotopes applied emit gamma photons in the energy range 60 keV ≤ E ≤ 600 keV.

If the radioisotope applied is not organ selective but suitable in all other aspects (eg. ^99mTc, E = 141 keV), the isotope should be linked to a pharmacon in order to ensure proper selectivity for the imaging method.

 

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