What is Tomographic Data

Quantitative three-dimensional nuclear medical imaging plays a continuously increasing role in radionuclide dosimetry, allowing the development of patient – specific treatment planning systems. The established method for dosimetry is based on the measurement of the biokinetics by serial gamma camera scans, followed by calculations of the administered activity and the residence times, resulting in the radiation absorbed doses of critical organs. However, the quantification of the activity in different organs from planar data is hampered by inaccurate attenuation and scatter correction as well as due to background and organ overlay (Glatting 2006). Alternatively, dosimetry based on quantitative three-dimensional data is more accurate and allows a more individualized approach, provided that all effects that degrade the quantitative content of the images have been corrected for. In addition inhomogeneous organ accumulation of the radionuclide can be detected and possibly taken into account (De Jong 2004). This chapter provides adequate information on internal emitter dosimetry and a state of the art review of the current methodology.