L.R factors.
On the other hand, SUV uptake can be higher in multiple myeloma(MM) patients, compared to the normal persons because there can be increased reactive osteoblastosis on the periphery of the MM lesions11. This further supports the fact that there is a difference in SUV values between the normal skeleton and the ones with metabolic bone diseases and cancers.
In a study of 47 bone tumors, Shin et al. reported a threshold SUV value of 3.7 26, while Duarte et al determined the SUVmax threshold for differentiation between malignant and benign bone lesions to be 2.5 27. Kurdziel et al reported that normal bone should have SUV of 10 or less on NaF18 PET/CT5. Currently, there is no consensus on the SUV cutoff in NaF18 studies. Metastasis is highly suspected in vertebra when the abnormally increased activity involves the vertebral bodies in addition to the contiguous pedicle and posterior element or when the configuration is rounded14. Patterns associated with benign lesions include a mild degree of abnormal activity, location along the plane of the disc space or at a facet joint, peripheral location, and linear configuration14. In screening for metastases sensitivity is more valuable than specificity because false-negative results can entail serious consequence for patients.
L.R Quantitative.
Although those articles suggested opportunities for the use of quantitative PET, they focused mainly on the clinical indications for (qualitative use of) 18F-FDG PET in oncology. In 1999, the EORTC PET Study Group(17) published a review of and recommendations for the measurement of clinical and subclinical tumor responses with 18F-FDG PET. That article discussed various methods for 18F-FDG PET data analysis, including visual inspection, use of semiquantitative indices, and full kinetic analysis. Several factors affecting 18F-FDG uptake measurements, such as partial-volume effects, applied region-of-interest definition, and blood glucose levels, were described. After a review of the assessment of tumor response, recommendations for patient preparation, timing of 18F-FDG PET scans, use of attenuation correction, 18F FDG dosage, quantification methods, and ROI methodology were made. On the basis of data available at that time on the testretest reproducibility of quantitative PET measures, quantitative criteria for assessing tumor response were proposed.
In 2005, Weber(9) reviewed the application of PET for monitoring cancer therapy and predicting outcome. That article discussed visual and quantitative response assessment with 18F-FDG PET and provided a detailed overview of factors affecting SUV outcome and quantification methods. Moreover, it discussed when and whether changes in 18F-FDG uptake may be considered significant and the issue of proper timing of 18F-FDG PET studies before and during treatment. Finally, the need for strict adherence to protocols for data acquisition, image reconstruction, and data analysis was emphasized. In 2005, Coleman et al.(31) summarized an intersociety dialogue on integrated imaging systems. That article provided an overviewof clinical applications for PET/CT, issues affecting PET/CT image quality and quantification (such as the effects of using contrast agents and patient motion during CT-based attenuation correction CT-AC), the need for qualified personnel, safety issues, and regulatory and legal issues. In 2006, Delbeke et al.(32), who also participated in that intersociety dialogue, provided guidelines for 18F-FDG PET/CT tumor imaging, including guidelines on patient preparation, intervention, the need for collection of other clinical information, CT and PET image acquisition procedures, uptake period, reconstruction and viewing, interpretation, QC, and qualification of personnel. That article provided an extensive point-by-point list of procedures and actions for performing PET/CT studies.
In the same year, Shankar et al.(35) published recommendations for the use of 18F-FDG PET to measure treatment responses in National Cancer Institute trials. Like earlier publications, that article described factors affecting SUVs and provided recommendations for patient preparation, image acquisition and reconstruction, timing of 18F-FDG PET studies during therapy, image analysis, and ROI methodology. The authors concluded that there is no single best methodology
for acquiring and analyzing 18F-FDG PET studies and that standardized protocols needed to be developed for NCI sponsored trials to assess when 18F-FDG PET could be used as a surrogate endpoint for determining therapeutic efficacy. Lammertsma et al.(18) discussed various methods for analyzing 18F-FDG PET studies performed to monitor tumor response. They emphasized the need for standardization. Moreover, they indicated that the relationship between SUVs and data obtained from a full kinetic analysis may be altered during (i.e., because of) treatment. In other words, the observed relative change in the SUV may under- or overestimate the response measured by a full quantitative outcome measure derived from a kinetic analysis. Consequently, the need to validate the use of simplified measures, such as the SUV, against a full kinetic analysis for response monitoring trials was stressed, as was also done by the EORTC PET Study Group(17).
Instruction files
suv_studies_1.docx(14,06 KiB)
