Combined imaging with 68Ga-DOTA-TATE and 18F-FDG PET/CT on the basis of volumetric parameters in neuroendocrine tumors.
OBJECTIVE
To assess the additional contribution of the combined imaging approach with Ga-DOTA-TATE and fluorine-18 fluorodeoxyglucose (F-FDG) on the basis of volumetric parameters in neuroendocrine tumors (NETs).


METHODS
Forty-one patients with NET (19 women, 22 men; age range: 30-79 years; mean age: 56.7±12.3 years) underwent Ga DOTA-TATE and F-FDG PET/computed tomography (CT) imaging. Within the drawn regions of interest, in addition to evaluating the maximum and mean standardized uptake values (SUVmax and SUVmean), the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in F-FDG PET/CT imaging, and the somatostatin receptor density and total lesion somatostatin receptor expression (TLSRE) in Ga somatostatin receptor imaging (SRI) were measured. The patients were graded on the basis of the proliferation index: well (G1; Ki-67 ≤2), moderately (G2; Ki-67=3-20), and poorly (G3; Ki-67>20) differentiated groups.


RESULTS
Of the 41 NET patients, 22, 14, and five were in the G1 (53.7%), G2 (34.1%), and G3 (12.2%) groups, respectively. Liver metastases had significantly higher TLSRE values than the TLG values. Ki-67 levels showed a positive correlation with the primary tumor MTV and TLG values. Cg-A levels had a positive correlation with the volumetric parameters of the whole-body tumor burden (P<0.001).


CONCLUSIONS
Ga SRI and F-FDG PET/CT provide complementary information on treatment protocol and response assessment. While assessing the prognosis and tumor aggressiveness, lesions and whole-body tumor burdens can be calculated on the basis of volumetric parameters by F-FDG PET/CT using MTV and TLG, and by Ga SRI using somatostatin receptor density and TLSRE.
Department of Nuclear Medicine, School of Medicine, Erciyes University, Kayseri, Turkey.
Ummuhan
U
Abdulrezzak
Yurdagul K
YK
Kurt
Mustafa
M
Kula
Ahmet
A
Tutus
D000328:Adult; D000368:Aged; D004338:Drug Combinations; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000473:pathology*; D009942:Organometallic Compounds / Q000008:administration & dosage*; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D047368:Tumor Burden
D004338:Drug Combinations; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C513399:gallium Ga 68 dotatate