TY - JOUR T1 - <sup>18</sup>F-FDG or 3′-Deoxy-3′-<sup>18</sup>F-Fluorothymidine to Detect Transformation of Follicular Lymphoma JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 216 LP - 221 DO - 10.2967/jnumed.114.149625 VL - 56 IS - 2 AU - Marielle J. Wondergem AU - Saiyada N.F. Rizvi AU - Yvonne Jauw AU - Otto S. Hoekstra AU - Nikie Hoetjes AU - Peter M. van de Ven AU - Ronald Boellaard AU - Martine E.D. Chamuleau AU - Saskia A.G.M. Cillessen AU - Josien C. Regelink AU - Sonja Zweegman AU - Josée M. Zijlstra Y1 - 2015/02/01 UR - http://jnm.snmjournals.org/content/56/2/216.abstract N2 - Considering the different treatment strategy for transformed follicular lymphoma (TF) as opposed to follicular lymphoma (FL), diagnosing transformation early in the disease course is important. There is evidence that 18F-FDG has utility as a biomarker of transformation. However, quantitative thresholds may require inclusion of homogeneous non-Hodgkin lymphoma subtypes to account for differences in tracer uptake per subtype. Moreover, because proliferation is a hallmark of transformation, 3′-deoxy-3′-18F-fluorothymidine (18F-FLT) might be superior to 18F-FDG in this setting. To define the best tracer for detection of TF, we performed a prospective a head-to-head comparison of 18F-FDG and 18F-FLT in patients with FL and TF. Methods: 18F-FDG and 18F-FLT PET scans were obtained in 17 patients with FL and 9 patients with TF. We measured the highest maximum standardized uptake value (SUVmax), defined as the lymph node with the highest uptake per patient, and SUVrange, defined as the difference between the SUVmax of the lymph node with the highest and lowest uptake per patient. To reduce partial-volume effects, only lymph nodes larger than 3 cm3 (A50 isocontour) were analyzed. Scans were acquired 1 h after injection of 185 MBq of 18F-FDG or 18F-FLT. To determine the discriminative ability of SUVmax and SUVrange of both tracers for TF, receiver-operating-characteristic curve analysis was performed. Results: The highest SUVmax was significantly higher for TF than FL for both 18F-FDG and 18F-FLT (P &lt; 0.001). SUVrange was significantly higher for TF than FL for 18F-FDG (P = 0.029) but not for 18F-FLT (P = 0.075). The ability of 18F-FDG to discriminate between FL and TF was superior to that of 18F-FLT for both the highest SUVmax (P = 0.039) and the SUVrange (P = 0.012). The cutoff value for the highest SUVmax of 18F-FDG aiming at 100% sensitivity with a maximum specificity was found to be 14.5 (corresponding specificity, 82%). For 18F-FLT, these values were 5.1 and 18%, respectively. When the same method was applied to SUVrange, the cutoff values were 5.8 for 18F-FDG (specificity, 71%) and 1.5 for 18F-FLT (specificity, 36%). Conclusion: Our data suggest that 18F-FDG PET is a better biomarker for TF than 18F-FLT PET. The proposed thresholds of highest SUVmax and SUVrange should be prospectively validated. ER -