Clinical Chapters
The American Cancer Society estimates that cancer currently accounts for approximately 23% of all deaths in the United States. In 2005, there were an estimated 1,372,910 new cancer cases with approximately 570,280 cancer- related deaths, or about 1500 deaths per day [1]. Clearly, cancer is one of the major foes that physicians and patients face. Fortunately, more battles are being won now than ever before thanks to improvements in public health and educa- tion, early detection, and treatment. PET/CT is one such advancement, and it has emerged as a major imaging tool to accurately diagnose, stage, and restage a variety of malignancies. While most PET utilization is in oncology, PET also has a valuable role to play in evaluating heart disease, dementia, and epilepsy.
The following chapters discuss the current state and future prospects of PET and PET/CT in oncology, cardiology, and neurology.
There are a few common themes connecting these chapters that should be discussed. First, fluorodeoxyglucose (FDG) is, by far, the most widely used PET radiopharmaceutical. Acting as a glucose analogue, FDG localizes within cells based upon their degree of glycolytic activity. Neoplasms exhibit unregulated growth that must be supported by increased metabolism; thus hypermetabolic foci are a hallmark of malignancy. A second point is that hypermetabolism is not always associated with malignancy, but can be seen with benign physiologic and inflammatory conditions. This limitation should always be kept in mind when considering and interpreting FDG-PET scans. Third, why is PET/CT so attractive? Nuclear medicine imaging with PET offers physicians valuable func- tional information, and radiographic imaging demonstrates exquisite anatomic detail, particularly with CT and MRI. With PET/CT, function and structure can now be viewed together, providing physicians with impressive insight into human disease. In 1993, while investigating visceral tumors, Wahl et al.
described the fusion of FDG-PET images with CT or MRI and coined the result- ing image an “anatometabolic” fusion image [2]. Now, use of anatometabolic imaging is entering mainstay medical practice, allowing increased confidence in assessing disease thanks to the merger of these two different, but complemen- tary imaging modalities. Finally, near the end of each clinical chapter, we discuss ongoing work beyond FDG with new and emerging PET radiopharmaceuticals that show tremendous promise in furthering the frontiers of functional imaging.
References
1. Jemal A, Murray T, Ward E, et al. Cancer statistics, 2005. CA Cancer J Clin 2005;
55(1):10–30.
2. Wahl RL, Quint LE, Cieslak RD, Aisen AM, Koeppe RA, Meyer CR. “Anatometabolic”
tumor imaging: fusion of FDG PET with CT or MRI to localize foci of increased activity. J Nucl Med 1993;34(7):1190–1197.
