If you wanted to measure the impact of a naturally occurring polymorphism on D4 binding, would you use PET, autoradiography, or homogenate binding? Why?© BrainMass Inc. brainmass.com October 10, 2019, 8:15 am ad1c9bdddf
Let's consider the advantages and limitations of each modality listed there, and then it should become a little more obvious.
Positron emission tomography (PET) is a great tool for identifying where within the human body, a radioactively tagged agent is metabolized. The radioactive component does not become so until the ligand it is bound to is metabolized, and so detection equipment will only pick up radioactivity from sources where tagged ligands like glucose is being used.
PET however, is only useful in so far as a macro-scale imaging technique. Most PET scans are full body scans for example, or at the very least, identifies macro-scale areas in an organ to target. Paired with CT scanning, PET-CT can more accurately identify where there are specific areas of higher metabolism, but at most, the resolution is on the millimeter scale.
Autoradiography describes a very broad spectrum of techniques, but overall describes the process of using either radioactive or fluorescent elements (e.g. antibodies) to tag specific ligands and using that emission to create images on sensitive detectors such as x-ray film. This is particularly useful when doing tissue whole mounts ...
A brief description and comparison of PET, autoradiography and homogenate binding, using the efficacy of each modality in determining the effect of polymorphisms on D4 receptor binding as an example to illustrate their strengths and limitations.