UNLABELLED: The primary goals of this study were to investigate the behavior of normal lung tissues after radiofrequency ablation (RFA) and to determine the suitability of 18F-FDG PET, using a dedicated small-animal scanner, for monitoring the early therapeutic effects of RFA on VX2 lung tumors (VX2s) in rabbits. METHODS: Fourteen Japanese white rabbits with normal lungs underwent RFA, followed by 18F-FDG PET at 1 d and at 1, 2, 4, and 8 wk. In addition, 7 rabbits with untreated VX2s underwent 18F-FDG PET, and 13 rabbits with RFA-treated VX2s underwent 18F-FDG PET at 1 d (n = 7) or 1 wk (n = 6) after the treatment. RESULTS: After RFA of normal lungs, ring-shaped accumulations of 18F-FDG, which coincided with inflammation caused by ablation, were observed. The mean early- (40-60 min after injection) and delayed (100-120 min)-phase ablated lesion-to-muscle ratios were, respectively, 2.9 +/- 1.0 and 3.3 +/- 0.8 (1 d), 4.1 +/- 0.6 and 5.2 +/- 0.9 (1 wk), 4.1 +/- 1.0 and 5.3 +/- 1.5 (2 wk), 3.1 +/- 0.5 and 3.6 +/- 1.1 (4 wk), and 1.8 +/- 0.1 and 2.3 +/- 0.1 (8 wk). At 4 and 8 wk, the uptake was less than that at 1 and 2 wk (P < 0.05). VX2s showed mean tumor-to-muscle ratios of 6.6 +/- 2.1 and 8.6 +/- 3.3 at the early and delayed phases, respectively. For ablated tumors, the respective ratios were 0.8 +/- 0.4 and 1.1 +/- 0.7 (1 d) and 1.2 +/- 0.5 and 1.5 +/- 0.7 (1 wk). These values were significantly lower than those for nonablated tumors (P < 0.001). Histopathologic examination confirmed the absence of viable tumors. 18F-FDG accumulation around ablated tumors reflected thermally damaged normal tissues and was significantly lower than that of control VX2s (P < 0.01). CONCLUSION: Our data suggest that 18F-FDG PET is promising for evaluating the therapeutic response of lung malignancies to RFA: Accumulation of 18F-FDG in surrounding normal tissues appears to be time dependent, and the data suggest that, clinically, 18F-FDG PET should be performed 4 wk or more after RFA. Delayed-phase images seem to better distinguish tumor from inflammation than do early-phase images.
UNLABELLED: The primary goals of this study were to investigate the behavior of normal lung tissues after radiofrequency ablation (RFA) and to determine the suitability of 18F-FDG PET, using a dedicated small-animal scanner, for monitoring the early therapeutic effects of RFA on VX2 lung tumors (VX2s) in rabbits. METHODS: Fourteen Japanese white rabbits with normal lungs underwent RFA, followed by 18F-FDG PET at 1 d and at 1, 2, 4, and 8 wk. In addition, 7 rabbits with untreated VX2s underwent 18F-FDG PET, and 13 rabbits with RFA-treated VX2s underwent 18F-FDG PET at 1 d (n = 7) or 1 wk (n = 6) after the treatment. RESULTS: After RFA of normal lungs, ring-shaped accumulations of 18F-FDG, which coincided with inflammation caused by ablation, were observed. The mean early- (40-60 min after injection) and delayed (100-120 min)-phase ablated lesion-to-muscle ratios were, respectively, 2.9 +/- 1.0 and 3.3 +/- 0.8 (1 d), 4.1 +/- 0.6 and 5.2 +/- 0.9 (1 wk), 4.1 +/- 1.0 and 5.3 +/- 1.5 (2 wk), 3.1 +/- 0.5 and 3.6 +/- 1.1 (4 wk), and 1.8 +/- 0.1 and 2.3 +/- 0.1 (8 wk). At 4 and 8 wk, the uptake was less than that at 1 and 2 wk (P < 0.05). VX2s showed mean tumor-to-muscle ratios of 6.6 +/- 2.1 and 8.6 +/- 3.3 at the early and delayed phases, respectively. For ablated tumors, the respective ratios were 0.8 +/- 0.4 and 1.1 +/- 0.7 (1 d) and 1.2 +/- 0.5 and 1.5 +/- 0.7 (1 wk). These values were significantly lower than those for nonablated tumors (P < 0.001). Histopathologic examination confirmed the absence of viable tumors. 18F-FDG accumulation around ablated tumors reflected thermally damaged normal tissues and was significantly lower than that of control VX2s (P < 0.01). CONCLUSION: Our data suggest that 18F-FDG PET is promising for evaluating the therapeutic response of lung malignancies to RFA: Accumulation of 18F-FDG in surrounding normal tissues appears to be time dependent, and the data suggest that, clinically, 18F-FDG PET should be performed 4 wk or more after RFA. Delayed-phase images seem to better distinguish tumor from inflammation than do early-phase images.
Authors: Francois Cornelis; Vlasios Sotirchos; Elena Violari; Constantinos T Sofocleous; Heiko Schoder; Jeremy C Durack; Robert H Siegelbaum; Majid Maybody; John Humm; Stephen B Solomon Journal: J Nucl Med Date: 2016-02-23 Impact factor: 10.057
Authors: Francois H Cornelis; Elena N Petre; Efsevia Vakiani; David Klimstra; Jeremy C Durack; Mithat Gonen; Joseph Osborne; Stephen B Solomon; Constantinos T Sofocleous Journal: J Nucl Med Date: 2018-02-09 Impact factor: 10.057
Authors: Yue Zhang; Sarah B White; Jodi R Nicolai; Zhuoli Zhang; Derek L West; Dong-Hyun Kim; A Lee Goodwin; Frank H Miller; Reed A Omary; Andrew C Larson Journal: Radiology Date: 2014-02-18 Impact factor: 11.105
Authors: Sumeet Virmani; Kathleen R Harris; Barbara Szolc-Kowalska; Tatjana Paunesku; Gayle E Woloschak; Fred T Lee; Robert J Lewandowski; Kent T Sato; Robert K Ryu; Riad Salem; Andrew C Larson; Reed A Omary Journal: J Vasc Interv Radiol Date: 2008-04-18 Impact factor: 3.464