ABSTRACT
Context Functional
positron emission tomography (
PET) imaging for the characterization of
pheochromocytoma and
paraganglioma (PCC/PGL) and for
detection of
metastases in malignant
disease, offers valuable clinical insights that can significantly guide
patient treatment.
Objective:
This
work aimed to evaluate a novel
PET radiotracer, 3-[18F]fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG), a
norepinephrine analogue, for its
ability to localize PCC/PGL.
Methods:
3-[18F]pHPG
PET/CT whole-body scans were performed on 16
patients (8
male8
female; mean age 47.6 ± 17.6 years; range, 19-74 years) with pathologically confirmed or clinically diagnosed PCC/PGL. After
intravenous administration of 304 to 475 MBq (8.2-12.8 mCi) of 3-[18F]pHPG, whole-body
PET scans were performed at 90 minutes in all
patients. 3-[18F]pHPG
PET was interpreted for abnormal findings consistent with primary
tumor or
metastasis, and biodistribution in normal organs recorded. Standardized uptake value (SUV) measurements were obtained for target lesions and physiological organ distributions.
Results:
3-[18F]pHPG
PET showed high radiotracer uptake and
trapping in primary
tumors, and metastatic
tumor lesions that included
bone,
lymph nodes, and other solid organ sites. Physiological biodistribution was universally present in
salivary glands (parotid, submandibular, sublingual),
thyroid,
heart,
liver, adrenals,
kidneys, and
bladder. Comparison [68Ga]DOTATATE
PET/CT was available in 10
patients and in all cases showed concordant distribution. Comparison [123I]
meta-iodobenzylguanidine [123I]
mIBG planar
scintigraphy and
SPECT/CT scans were available for 4
patients, with 3-[18F]pHPG showing a greater number of metastatic lesions.
Conclusion:
We found the kinetic profile of 3-[18F]pHPG
PET affords high activity retention within benign and metastatic PCC/PGL. Therefore, 3-[18F]pHPG
PET imaging provides a novel modality for functional imaging and staging of malignant
paraganglioma with advantages of high lesion affinity, whole-body coregistered computed
tomography, and rapid same-day imaging.