PET/CT Lung Ventilation and Perfusion Scanning using Galligas and Gallium-68-MAA.

Ventilation/Perfusion (V/Q) positron emission tomography computed tomography (PET/CT) is now possible by substituting Technetium-99m (99mTc) with Gallium-68 (68Ga), using the same carrier molecules as conventional V/Q imaging. Ventilation imaging can be performed with 68Ga-carbon nanoparticles using the same synthesis device as Technegas. Perfusion imaging can be performed with 68Ga-macroaggregated albumin. Similar physiological processes can therefore be evaluated by either V/Q SPECT/CT or PET/CT. However, V/Q PET/CT is inherently a superior technology for image acquisition, with higher sensitivity, higher spatial and temporal resolution, and superior quantitative capability, allowing more accurate delineation and quantification of regional lung function. Additional advantages include reduced acquisition time, respiratory-gated acquisition, and a lower impact on human resources. V/Q PET imaging offers an opportunity to improve the accuracy and utility of V/Q imaging in various pulmonary conditions. For pulmonary embolism, V/Q PET/CT scan may improve the diagnostic performance of the test owing to a better characterization of the pattern of defects and allow an accurate quantification of the extent of vascular obstruction. Establishing an accurate functional map of the regional ventilation and perfusion in the lungs may be relevant in many other clinical situations, including preoperative assessment of the lung cancer patients, radiotherapy planning, or presurgical evaluation of patients undergoing lung volume reduction surgery.