title: Uptake of [N-methyl-11C]alpha-methylaminoisobutyric acid in untreated head and neck cancer studied by PET.
abstract: Amino acid transport system A is expressed strongly in neoplastic cells. [ N-methyl-(11)C]alpha-Methylaminoisobutyric acid ((11)C-MeAIB) is a recently developed tracer for PET studies on system A amino acid transport. (11)C-MeAIB is a metabolically stable amino acid analogue which is transported from plasma into the tissue by system A. This study evaluated the kinetics of (11)C-MeAIB uptake from plasma into tumour tissue and normal tissues in 13 patients with untreated head and neck cancer. (11)C-MeAIB uptake in tumour was compared with histological grade and proliferative activity. Tracer uptake was quantitated by calculating the standardised uptake values (SUVs) and the kinetic influx constants ( K(i)) using graphical analysis. All tumours accumulated (11)C-MeAIB and were visualised clearly. In the graphical analysis, linear plots were achieved; the mean K(i) value of tumour was 0.056+/-0.026 min(-1), and the mean SUV was 6.1+/-2.7. A close correlation between graphically obtained K(i) and semi-quantitative SUV in tumours was found ( r=0.887, P=0.00005). We could not demonstrate a correlation between the uptake of (11)C-MeAIB and the grade of malignancy or the proliferative index, as assessed using Ki-67 immunohistochemical assay. Head and neck cancer can be effectively imaged with (11)C-MeAIB PET. (11)C-MeAIB showed active and rapid transport into tumour tissue and salivary glands. Further studies on the applicability of (11)C-MeAIB PET for radiation treatment planning in the head and neck region and the regulation of system A amino acid transport under different metabolic states are warranted.
authors.affiliation: Turku PET Centre, Turku University Central Hospital, Turku, Finland. eija.sutinen@pet.tyks.fi
authors.forename: Eija
authors.initials: E
authors.lastname: Sutinen
authors.forename: Sirkku
authors.initials: S
authors.lastname: Jyrkkiö
authors.forename: Kalle
authors.initials: K
authors.lastname: Alanen
authors.forename: Kjell
authors.initials: K
authors.lastname: Någren
authors.forename: Heikki
authors.initials: H
authors.lastname: Minn
mesh_terms: D000328:Adult; D000368:Aged; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics*; D003528:Carcinoma, Adenoid Cystic / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000556:secondary; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D018307:Neoplasms, Squamous Cell / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000556:secondary; D009928:Organ Specificity; D019275:Radiopharmaceuticals / Q000494:pharmacology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed / Q000379:methods*; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D015091:beta-Alanine; C012924:2,2-dimethyl-beta-alanine