Influence of tumour size and uptake of 99mTc-octreotide on radio-guided surgery for neuroendocrine tumors.
OBJECTIVE
The aim of this study was to analyze the influence of scintigraphic uptake grade and tumour size on radio-guided surgery of neuroendocrine tumours (NETs) using 99mTc-EDDA/HYNIC-TOC (99mTc-octreotide).


METHODS
We investigated 21 patients with NET (F=8, M=13) for localization of 27 known lesions using a gamma probe. Three to 6 hours before surgery, 550-650 MBq of 99mTc-octreotide was injected followed by immediate imaging prior to surgery. The uptake was graded on a scale from 0-4. Localization was confirmed by endoscopic ultrasound (EUS), computed tomography (CT) and/or magnetic resonance imaging (MRI). Morphological images were used to determine size of the lesion. Local measurements of radioactivity were performed during surgery using a gamma probe.


RESULTS
Twenty lesions were successfully localized intraoperatively using a gamma probe (7=grade 4, 9=grade 3, 2=grade 2 and 2=grade 0). The size of successfully localized lesions ranged between 9 and 50 mm. Seven lesions were not localized successfully of which 6 were seen on scintigraphy (2=grade 4, 1=grade 3 and 3=grade 2). The 7th lesion was not seen on preoperative scintigraphy and not localized successfully. The size of unsuccessfully localized lesions ranged between 7 and 30 mm.


CONCLUSIONS
High octreotide uptake (grade 3 and 4) influence radioguided surgery. Tumour size did not influence the success of localization of lesions by gamma probe.
Hodolic
M
M
Department of Nuclear Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia. marina.hodolic@kclj.si
Fettich
J
J
Rubello
D
D
D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D015282:Octreotide / Q000031:analogs & derivatives*; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome
C493098:99mTc-octreotide; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D015282:Octreotide