In vitro methods for in vivo quantitation of PET and SPECT imaging probes: Autoradiography and gamma counting

Abstract

By measuring the efficiencies of each radioactivity sensing device, the resulting data can be converted into a common unit of reference, usually either Becquerel or Curies. This conversion into the same unit makes it possible to compare values across different types of measurement systems, making use of the value of each system, whether it be high spatial resolution or in vivo measurements over hours or days. To be accurate, the various corrections and calibration factors must be carefully measured and applied. Fortunately, regular assessments of the calibration factors are an excellent quality control measure and are relatively simple to obtain. Combining autoradiography with in vivo imaging is challenging but certainly possible, enabling more exact knowledge of the precise location of the imaging probe used in vivo. © 2011 Springer-Verlag Berlin Heidelberg.