Impact of peptide receptor radionuclide therapy on the 68Ga-DOTATOC-PET/CT uptake in normal tissue.
OBJECTIVE
Positron-emission tomography/computed tomography (PET/CT) with [68Ga]DOTA0-Phe1-Tyr3-octreotide (68Ga-DOTA-TOC) became a standard for somatostatin receptor imaging. We investigated the potential changes of normal tissue uptake in patients with neuroendocrine tumor undergoing peptide receptor radionuclide therapy (PRRT).


METHODS
Sixteen patients underwent [68Ga]-DOTA-TOC-PET/CT prior and after 4-6 cycles of PRRT (mean administered activity: 13.8 GBq 90Y+ 9.6 177Lu). The maximum standardized uptake values (SUVmax) of pituitary, thyroid, spleen, liver parenchyma, pancreas, kidneys and adrenals were determined, respectively.


RESULTS
SUVmax values prior and after PRRT were in pituitary (5, 56±2,91/ 4,47±2,53), thyroid (2.05±1.11/ 2.49±2.47), spleen (24.95±14.20/20.06±8.53), liver (7.13±3.96/6.62±2.63), pancreas (6.96±1.99/6.83±2.00), kidneys (13.0±3.85/11.31±3.31) and adrenals (9.65± 4.20/7.10±2.86). A comparison of pre- and post treatment values revealed no significant differences (P>0.05) in any of these organs.


CONCLUSIONS
The uptake of [68Ga] DOTA-TOC in normal tissue is not significantly affected by PRRT. This is relevant with regards to therapeutic monitoring were tumor-to-non-tumor ratio seems to be the most robust biomarker.
Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany. frederik@egiesel.com
F L
FL
Giesel
M
M
Stefanova
L H
LH
Schwartz
A
A
Afshar-Oromieh
M
M
Eisenhut
U
U
Haberkorn
C
C
Kratochwil
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000378:metabolism* / Q000532:radiotherapy*; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D009928:Organ Specificity; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use; D018000:Receptors, Peptide / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D015203:Reproducibility of Results; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed
C499142:Ga(III)-DOTATOC; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D018000:Receptors, Peptide; D015282:Octreotide