ABSTRACT
Nuclear medicine has been available as an imaging technology first in planar form in the 1950s and since the late 1960s as a tomographic technique. It is an extremely sensitive technique capable of measuring concentrations in the nanomolar to picomolar range. Using tracer technology, it provides functional information about a large number of different organs and systems within the human body. However, its poor spatial resolution and the often specific nature of the tracer uptake made the images difficult to understand for the untrained eye and earned nuclear medicine the moniker “unclear medicine” (von Schulthess 2004, Patel et al. 2009). The value of an anatomical reference had long been recognized and transmission/emission imaging had been proposed as early as 1966 (Kuhl et al. 1966). Many nuclear medicine studies like ventilation–perfusion scans and sentinel-node lymphoscintigra-phy are frequently interpreted with side-by-side reference to an anatomical image, be it a chest x-ray or a crude body outline formed by the shadow of a flood transmission source.
