abstract
- A number of factors impact the accuracy of activity quantitation in planar and single photon emission computed tomographic (SPECT) imaging. Two important such factors are attenuation and scattering in the medium containing the activity. The first removes photons which otherwise would have been included in the images, and the second adds events to the images from photons which would not have otherwise been imaged. A number of methods have been developed to compensate for these biases to activity quantitation. This review will briefly introduce planar quantitation which is commonly used for dosimetric purposes, and then present a slightly more detailed overview of SPECT quantitation which is arguably more accurate. It will conclude by cautioning users of commercial reconstruction software to validate it for quantitation before using it for dosimetric purposes.