Effect of Respiratory Motion on Positron Emission Tomography Imaging

This study will determine how breathing motions may affect positron emission tomography (PET) scans. It has been discovered that the quality of PET scans varies according to which part of the breathing cycle patients hold their breath. NIH Clinical Center patients 12 years of age and older who are scheduled to have PET and computed tomography (CT) scans as part of their standard medical care may be eligible for this study. Participants have their scheduled PET or CT scan as they normally would and are asked to hold their breath after breathing out, as is usual. In addition, for this study, patients are also asked hold their breath after breathing in and again at a point between breathing in and out. Each breath-hold is for around 15 seconds. The scans for each of the three different breath-holds are examined for differences. Some patients may also be asked to breathe through a tube called a pneumotachometer, or spirometer, to determine their normal breathing pattern. This involves breathing through a mouthpiece similar to a snorkel mouthpiece and takes about 2 minutes.