[۱۸F]FMISO PET in metastatic neuroendocrine tumours: a pilot study

AbstractBackground: The phenomenon of peripheral [۶۸Ga]DOTATATE avidity without central avidity (which we have termed a “DONUT") has been observed in neuroendocrine neoplasm (NEN) lesions. There has been speculation as to whether this is due to hypoxia, de-differentiated disease or other causes. The presence of hypoxia may have prognostic and therapeutic implications, and was evaluated in these lesions using the PET hypoxia imaging biomarker [۱۸F]FMISO.Materials and methods: Prospective pilot study in patients with metastatic NENs with at least one DONUT lesion (central [۶۸Ga]DOTATATE non-avidity). [۱۸F]FDG and [۱۸F]FMISO scans were acquired within ۶۰ days of the [۶۸Ga]DOTATATE PET/CT. [۱۸F]FMISO scans were acquired as a dynamic scan over ۲۰ mins from injection with a delayed image at ۲ hours. The dynamic acquisition was analysed quantitatively using a graphical approach yielding parametric images of Influx Rate Constant and Volume of Distribution. [۱۸F]FMISO uptake within the identified DONUT hole on the ۲ hr delayed scan was qualitatively scored by two experienced nuclear medicine physicians as: ۰ (no uptake), ۱ (uptake less than normal liver), ۲ (uptake equal to normal liver), or ۳ (uptake greater than normal liver).Results: Ten patients were enrolled with primary sites including pancreas (n=۳), small bowel (n=۳), rectum (n=۲), duodenum (n=۱) and lung (n=۱). Six subjects were scored ۱, three subjects were scored ۲, and one subject was scored ۳. All lesions evaluated were located in the liver. Quantitative [۱۸F]FMISO parametric imaging showed evidence of increased uptake rate (Ki) in the photopenic areas of the DONUT lesions in ۸/۱۰ subjects. Surrounding uptake rate in normal liver was extremely low. In the qualitative delayed image assessment, only one subject demonstrated [۱۸F]FMISO uptake greater than surrounding normal liver (small bowel primary, G۲).Conclusion: Only one of ten patients with DONUT lesions demonstrated Increased [۱۸F]FMISO uptake rate on delayed static imaging. In contrast, dynamic imaging demonstrated increased [۱۸F]FMISO uptake rate in the region of [۶۸Ga]DOTATATE photopenia on ۸ of ۱۰ patients. Future research using [۱۸F]FMISO in NEN patients should incorporate dynamic imaging.

کلیدواژه ها:

Hypoxia ، [۱۸F]FMISO ، [۶۸Ga]DOTATATE ، [۱۸F]FDG ، PET/CT ، neuroendocrine tumours (NETs)