Page 103 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors

Distribution of PSMA-ligand in salivary and lacrimal glands on PET/CT
Materials and methods
The distribution of healthy salivary and seromucous gland tissues in the head and neck area was retrospectively analysed in 30 consecutive patients who underwent total body PSMA PET/CT for staging of prostate cancer in March and April 2016. Exclusion criteria were previous salivary gland disease, aberrant tracer uptake suspected of neoplasia, and previous surgery and/or radiotherapy in the head and neck region.
PSMA PET/CT: Specific patient preparation was not required before PET/CT
imaging. Images were acquired from the skull vertex to the thighs using a TruePoint
Biograph mCT40 scanner (Siemens, Erlangen, Germany), approximately 60
minutes after intravenous injection of 2 MBq/kg 68Ga-HBED-CC-Glu-NH-CO-
NH-Lys (Ahx). A low dose CT scan was performed using Care Dose 4D and Care kV
(Siemens, Erlangen, Germany) with the following reference parameters: 40 mAs,
120 kV. Subsequently, PET was acquired according to the European Association 6 of Nuclear Medicine recommendations with the following parameters: PET with time-of-flight and point spread function (TrueX) reconstruction, 4 iterations, 21
subsets, with a filter of 7.5mm full width at half maximum [8].
PSMA-ligand uptake: Tracer uptake in the head and neck was determined visually and quantitatively by a dedicated board-certified head and neck nuclear medicine physician (B.d.K.) experienced in PSMA PET/CT, in consensus in a joint session with an oral and maxillofacial surgeon (T.K.N.) Visibility was defined as visually recognizable by increased tracer uptake relative to surrounding mucosa and other normal tissues. Quantitative evaluation was performed by calculating the maximum standardized uptake value (SUVmax) using a freehand isocontour volume of interest and the lean body mass formula, as defined in the European Association of Nuclear Medicine guidelines [8]. In the event of disagreement on gland location margins, a forced consensus was reached. Uptake in the parotid, submandibular, sublingual, pharyngeal, and lacrimal glands was measured bilaterally.
Data analysis: Normal distribution of the SUVmax was evaluated per gland location using the Shapiro-Wilk test. The mean SUVmax ± standard deviation (SD) and range were calculated according to each gland location. Overall variations in SUVmax of the paired glands were reported, and intra-individual differences were
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