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Purpose: The Response Evaluation Criteria in Solid Tumors (RECIST) are widely used but have recognized limitations. Molecular imaging assessments, including changes in F-deoxyglucose (FDG) or F-deoxythymidine (FLT) uptake by positron emission tomography (PET), may provide earlier, more robust evaluation of treatment efficacy. Methods: A prospective trial evaluated on-treatment changes in FDG and FLT PET imaging among patients with relapsed or recurrent non-small cell lung cancer treated with erlotinib to assess the relationship between PET-evaluated response and clinical outcomes. We describe an audit of compliance with the study imaging charter, to establish the feasibility of achieving methodological consistency in a multicentre setting. Results: Patients underwent PET scans at baseline and approximately day 14 and day 56 of treatment ( n = 73, 66 and 51 studies, and n = 73, 63 and 50 studies for FDG PET and FLT PET, respectively). Blood glucose levels were within the target range for all FDG PET scans. Charter-specified uptake times were achieved in 86% (63/73) and 89% (65/73) of baseline FDG and FLT scans, respectively. On-treatment scans were less consistent: 72% (84/117) and 68% (77/113), respectively, achieved the target of ±5 min of baseline uptake time. However, 96% (112/117) and 94% (106/113) of FDG and FLT PET studies, respectively, were within ±15 min. Bland-Altman analysis of intra-individual hepatic average standardized uptake value (SUV), to assess reproducibility, showed only a small difference in physiological uptake (−0.006 ± 0.224 in 118 follow-up FDG scans and 0.09 ± 0.81 in 111 follow-up FLT scans). Conclusion: It is possible to achieve high reproducibility of scan acquisition methodology, provided that strict imaging compliance guidelines are mandated in the study protocol. [ABSTRACT FROM AUTHOR]

Recently the potential of whole-body positron emission tomography scanning using [sup 18] F-fluorodeoxyglucose (FDG PET) has led to renewed interest in the use of functional imaging for the detection of occult metastatic melanoma. This study compared dedicated FDG PET with high-dose gallium-67 imaging incorporating whole-body scanning and comprehensive single-photon emission tomography (SPET) in 122 cases (121 patients) in which the two scans were performed <6 weeks apart. All patients were at high clinical risk of occult metastatic disease and 49 (40%) had abnormality suggestive of metastatic disease by at least one functional imaging technique. Discrepant scan findings were followed up to determine which technique more accurately reflected disease status. There were 23/122 (19%; 95% CI: 12%–26%) cases with discordant scan results in respect of either the presence of melanoma (11 cases) or the extent of disease (12 cases). PET correctly identified more disease than [sup 67] Ga SPET in 14 cases (including three incidental primary tumours) and was true negative in three further patients with abnormal [sup 67] Ga SPET. There were six patients with true positive [sup 67] Ga SPET in whom FDG PET was false negative (one small cutaneous deposit, one residual axillary node rated equivocal on FDG PET due to postoperative changes, one adrenal metastasis inseparable from renal activity on FDG PET and three cases in which sites missed on FDG PET were seen on [sup 67] Ga SPET. Thus, FDG PET provided incremental diagnostic information compared with [sup 67] Ga SPET in 17/23 patients, while [sup 67] Ga SPET provided incremental information compared with PET in 6/23 cases (P=0.035). Based on Australian Medicare reimbursement levels, the net cost per patient with clinical management benefit of replacing [sup 67] Ga SPET with FDG PET was estimated to be less than EUR 1,750. These results suggest that FDG PET provides incremental and clinically important information in... [ABSTRACT FROM AUTHOR]