TY - JOUR T1 - <sup>18</sup>F-CPFPX PET Identifies Changes in Cerebral A<sub>1</sub> Adenosine Receptor Density Caused by Glioma Invasion JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 450 LP - 454 VL - 46 IS - 3 AU - Andreas Bauer AU - Karl-Josef Langen AU - Hans Bidmon AU - Marcus H. Holschbach AU - Simone Weber AU - Ray A. Olsson AU - Heinz H. Coenen AU - Karl Zilles Y1 - 2005/03/01 UR - http://jnm.snmjournals.org/content/46/3/450.abstract N2 - Adenosine plays a critical role in both tumor proliferation and the cerebral response to tumor invasion. We used 8-cyclopentyl-3-(3-18F-fluoropropyl)-1-propylxanthine (18F-CPFPX) PET to investigate A1 adenosine receptor (A1AR) density as a potential indicator of the local cerebral response to glioma invasion. Methods: A1AR density in F98 glioma–bearing rats was examined by 18F-CPFPX and 3H-CPFPX using PET, quantitative in vitro and ex vivo double-label receptor autoradiography, and immunohistochemical analyses. Results: For all imaging modalities, A1AR signal intensity was increased in a zone surrounding experimental tumors (136%–146% that in control tissue) (P &lt; 0.01). Immunostaining identified activated astrocytes as the main origin of peritumoral A1AR upregulation. The results of a pilot 18F-CPFPX PET study on a patient with recurrent glioblastoma multiforme confirmed increases in A1AR density in the immediate vicinity of the tumor. Conclusion: 18F-CPFPX PET is suitable for the detection of peritumoral changes in A1AR density. Molecular imaging with 18F-CPFPX PET may open novel possibilities for gaining experimental and clinical insights into the cerebral response to tumor invasion. ER -