Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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PET with the glucose analog 18F-FDG is increasingly being used to monitor the effectiveness of therapy in patients with malignant lymphomas and a variety of solid tumors. The use of integrated PET/CT instead of stand-alone PET for treatment monitoring poses some methodologic challenges for the quantitative analysis of PET scans but also provides the opportunity to integrate morphologic information and functional information. ⋯ This review addresses how CT-based attenuation correction may affect the quantitative analysis of 18F-FDG PET scans and summarizes the results of recent studies with PET/CT for treatment monitoring for lung cancer and gastrointestinal stromal tumors. The review concludes with an outlook on how PET/CT could make a difference in drug development and clinical management for patients.
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Early detection of recurrence is clinically important and can improve the prognosis and survival of patients with cancer. CT, considered the primary method of investigation because of its low cost and widespread availability, provides high-resolution anatomic details but may underestimate the actual tumor burden by overlooking small tumor clusters in areas of distorted anatomy after treatment. 18F-FDG PET is an effective whole-body imaging technique that detects metabolic changes preceding structural findings. ⋯ PET/CT provides fused images that demonstrate the complementary roles of functional and anatomic assessments in the diagnosis of cancer recurrence through the precise localization of suspected 18F-FDG foci and their characterization as malignant or benign. In addition to the accurate diagnosis and definition of the whole extent of recurrent cancer, PET/CT has an impact on patient management because it can assist in defining potential candidates for surgery for cure, planning the appropriate surgical or radiotherapy approach, and referring patients with unresectable disease to other therapeutic options.
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Screening for cancer remains a very emotional and hotly debated issue in contemporary medical practice. An analysis of published data reveals a multitude of opinions based on a limited amount of reliable data. Even for breast cancer screening, which is now widely practiced in the United States and many European countries, there is continuing controversy regarding the appropriate age limits for screening mammography and, in fact, concerning the value of mammography itself. ⋯ Because of prohibitive costs and the required length of follow-up, it is unlikely that such a trial will ever be conducted. Rather than spending time and resources on screening studies, medical practitioners should continue using whole-body PET/CT for diagnosing, staging, and restaging cancer and for monitoring treatment effects. Researchers should also investigate the utility of whole-body PET/CT for the surveillance of selected groups of patients who have cancer, who have completed curative treatment, but who remain at high risk for recurrent disease.
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There have been major advances in PET technology that cumulatively have helped improve image quality, increased the range of applications for PET, and contributed to the more widespread use of PET. Examples of these technologic advances include whole-body imaging, 3-dimensional imaging, new scintillator materials, iterative reconstruction algorithms, combined PET/CT, and preclinical PET. ⋯ Although, conceptually, huge gains in sensitivity are still possible, realizing these gains is thwarted largely by economic rather than scientific concerns. Predicting the future is fraught with difficulty; nonetheless, it is apparent that ample opportunities remain for new development and innovation in PET technology that will be driven by the demands of molecular medicine, notably sensitive and specific molecular diagnostic tools and the ability to quantitatively monitor therapeutic entities that include small molecules, peptides, antibodies, nanoparticles, DNA/RNA, and cells.