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Cardiac PET imaging differs from oncology PET due to cold area detection and quantitation in the heart as compared to hot spot detection in whole-body FDG imaging for oncology. To assess reconstruction and acquisition settings for cold area imaging, a phantom containing six cold spheres, cold-rod sets and a uniform activity area was imaged on a dedicated PET-CT system using F-18 over a range of scanning conditions, activities and acquisition times. Count levels of 10, 20, 50, 200 and 650M counts were repeatedly acquired over a range of phantom total activity comparable to that which can be encountered in cardiac PET studies. Analysis included calculation of noise equivalent counts (NEC) and analysis of contrast versus background variability for each scan reconstructed with different OSEM iterations and filters and with FBP using various filters. For all count and NEC levels, higher and more consistent cold area contrast recovery was found with FBP reconstruction as compared to OSEM. In general, higher noise was found with FBP as compared to OSEM, but the difference diminished as the total counts increased into the range for cardiac PET. Therefore, FBP reconstruction methods should be considered in place of OSEM for cold feature imaging in cardiac PET

The use of a conventional small volume [ 18 O]water target gave rise to two problems. First, the water tendedto be expelled from the target by radiolytic gas production and second, continued use of the target gave [ 18 F]fluoride which could not be used for organic synthesis due to metal ions dissolving in the target water. Both of these problems have been overcome by using a silver target with a head space that permits the gas to leave the target without removing water.

Dynamic cardiovascular imaging plays a vital role in the diagnosis and treatment of cardiac disease by providing information about the function of the heart. During the past 30 years, cardiovascular imaging has evolved from the simple chest x-ray and fluoroscopy to such sophisticated techniques as invasive cardiac angiography and cinearteriography and, more recently, to noninvasive cardiac CT scanning, nuclear magnetic resonance, and positron emission tomography, which reflect more complex physiologic functions. As research tools, CT, NMR, and PET provide quantitative information on global as well as regional ventricular function, coronary artery stenosis, myocardial perfusion, glucose and fatty acid metabolism, or oxygen utilization, with little discomfort or risk to the patient. As imaging modalities become more sophisticated and more oriented toward clinical application, the prospect of routinely obtaining such functional information about the heart is becoming realistic. However, these advances are double-edged in that the interpretation of functional data is more complex than that of the anatomic imaging familiar to most physicians. They will require an enhanced understanding of the physiologic and biochemical processes, as well as of the instrumentation and techniques for analyzing the data. Of the new imaging modalities that provide functional information about the heart, PET is themore » most useful because it quantitates the regional distribution of radionuclides in vivo. Clinical applications, interpretation of data, and the impact of PET on our understanding of cardiac pathophysiology are discussed. 5 figures.« less