Different distribution of ⁶²Cu ATSM and ¹⁸F-FDG in head and neck cancers

PURPOSE:: [Cu]-diacetyl-bis(N4-methlythiosemicarbazone) (Cu-ATSM) was used to delineate hypoxic tissue in head-and-neck cancer, and its distribution was compared with that of F-FDG. MATERIALS AND METHODS:: Thirty patients with head-and-neck cancer underwent Cu-ATSM and FDG PET within a 1 week interval. Accumulation of tracer for each PET image was converted to SUV. After coregisteration of PET images with individual anatomic images, multiple small ROIs were drawn on the tumor mass and applied to both PET images. SUV values were obtained for all ROIs (SUVroi), and the SUVroi regression lines between Cu-ATSM and FDG of each tumor were determined. RESULTS:: The SUV mean of Cu-ATSM was lower than that of FDG for both squamous cell carcinoma (SCC) and adenocarcinoma (P < 0.05). In 27 patients with SCC, Cu-ATSM accumulated higher in the peripheral region than in the center of the tumor, and FDG showed the other tendency. Thus, the relationship of the SUVroi for Cu-ATSM and FDG showed a negative correlation in SCC. However, 3 adenocarcinoma cases showed similar and homogenous accumulation in the tumor mass with a positive SUVroi correlation for the 2 tracers. The regression slope means were -0.12 ± 0.08 for SCC (n = 27) and 0.28 ± 0.12 (n = 3) for adenocarcinoma. CONCLUSION:: In patients with head-and-neck cancer, intratumoral distribution of Cu-ATSM and FDG showed a negative correlation in SCC and a positive correlation in adenocarcinoma. The 2 tracers represented different pathophysiological microenvironments in different tumors, suggesting that noninvasive hypoxic tissue imaging with Cu-ATSM would be beneficial in the pretreatment evaluation of head-and-neck cancer.