Dynamic PET (dPET) studies have been used until now primarily within research purposes. Although it is generally accepted that the information provided by dPET is superior to that of conventional static PET acquisitions acquired usually 60 min post injection of the radiotracer, the duration of dynamic protocols, the limited axial field of view (FOV) of current generation clinical PET systems covering a relatively small axial extent of the human body for a dynamic measurement, and the complexity of data evaluation have hampered its implementation into clinical routine. However, the development of new-generation PET/CT scanners with an extended FOV as well as of more sophisticated evaluation software packages that offer better segmentation algorithms, automatic retrieval of the arterial input function, and automatic calculation of parametric imaging, in combination with dedicated shorter dynamic protocols, will facilitate the wider use of dPET. This is expected to aid in oncological diagnostics and therapy assessment. The aim of this review is to present some general considerations about dPET analysis in oncology by means of kinetic modeling, based on compartmental and noncompartmental approaches, and parametric imaging. Moreover, the current clinical applications and future perspectives of the modality are outlined.

To evaluate positron emission tomography (PET) using 2-fluoro-2-deoxy-D-glucose (FDG) for clinical application in soft tissue sarcomas. FDG PET is a promising noninvasive method for the preoperative assessment of soft tissue sarcomas and may complement radiologic tomography. Data from 50 consecutive patients with 59 masses, either suspicious for primary or locally recurrent soft tissue sarcoma, were prospectively gathered. The semiquantitative FDG uptake (standardized uptake values [SUVs]) was calculated in tumor and normal tissue (muscle). Histopathology of surgical specimens and follow-up data were used as control criteria. In primary soft tissue sarcomas, PET displayed a sensitivity of 91% and a specificity of 88%. Local recurrence was detected with a sensitivity of 88% and a specificity of 92%. All intermediate-grade and high-grade soft tissue sarcomas (primary and locally recurrent) were visualized with a precise differentiation from muscle. Fifty percent of the low-grade sarcomas showed an FDG uptake equivalent to muscle (false-negative results in one primary and three recurrent soft tissue sarcomas). Benign soft tissue tumors (e.g., lipoma, leiomyoma, ganglion) did not accumulate FDG. Inflammation resulted in an increased FDG uptake. The semiquantitative FDG uptake (SUVs) correlated with tumor grade but not with size and histologic type. High-grade and intermediate-grade soft tissue sarcomas are amenable to PET imaging, whereas low-grade lesions may not be depicted. SUVs for FDG correlate with tumor grade in soft tissue sarcomas. Benign soft tissue tumors are differentiated from higher-grade soft tissue sarcomas. These data show that FDG-PET can complement preoperative radiologic assessment for soft tissue sarcomas and that FDG-PET is a powerful diagnostic tool for detecting high-grade and intermediate-grade local recurrence.