A brief history of gamma scintigraphy

Gamma scintigraphy involves the radiolabeling of inhaled drug formulations, followed by in vivo imaging of deposition in two dimensions. This permits whole lung deposition to be quantified as mass of drug or percentage of the dose, and regional deposition patterns to be assessed. Gamma scintigraphy is the method by which the majority of inhaled drug deposition data have be en obtained, and scintigraphic studies have become viewed as milestone asse ssments in the development of new pulmonary drug products. Lung deposition data are used to show "proof of concept" in vivo for these products, and ac t as a bridge between in vitro laboratory testing and a clinical trials pro gram. Gamma scintigraphy is likely to remain the method of choice for asses sing inhaled drug deposition for some time to come.