Pretreatment evaluation of carcinomas of the hypopharynx and larynx with 18F-fluorodeoxyglucose, 123I-alpha-methyl-L-tyrosine and 99mTc-hexakis-2-methoxyisobutylisonitrile.
While fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is helpful in the pretherapeutic evaluation of head and neck cancer, it is only available in selected centres. Therefore, single-photon emission tomography (SPET) tracers would be desirable if they were to demonstrate tumour uptake reliably. This multitracer study was performed to evaluate the pretherapeutic uptake of the SPET tracers iodine-123 alpha-methyl-L-tyrosine (IMT) and technetium-99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) in primary carcinomas of the hypopharynx and larynx and to compare the results with those of FDG PET. We examined 22 fasted patients (20 male, 2 female, mean age 60.5+/-10.2 years) with histologically confirmed carcinoma of the hypopharynx (n=9) or larynx (n=13), within 1 week before therapy. In 20 patients a cervical PET scan was acquired after intravenous injection of 232+/-43 MBq 18F-FDG. Data analysis was semiquantitative, being based on standardised uptake values (SUVs) obtained at 60-90 min after injection. After injection of 570+/-44 MBq 99mTc-MIBI, cervical SPET scans (high-resolution collimator, 64x64 matrix, 64 steps, 40 s each) were obtained in 19 patients, 15 and 60 min after tracer injection. Finally, 15 min after injection of 327+/-93 MBq 123I-IMT (medium-energy collimator, 64x64 matrix, 64 steps, 40 s each) SPET scans were acquired in 15 patients. All images were analysed visually and by calculating the tumour to nuchal muscle ratio. Eighteen of 20 (90%) carcinomas showed an increased glucose metabolism, with a mean SUV of 8.7 and a mean carcinoma to muscle ratio of 7.3. The IMT uptake was increased in 13 of 15 (87%) patients, who had a mean carcinoma to muscle ratio of 2.9. Only 13 of 19 (68%) carcinomas revealed pathological MIBI uptake, with a mean tumour to muscle ratio of 2.2 and no significant difference between early and late MIBI SPET images (P=0.23). In conclusion, in the diagnosis of primary carcinomas of the hypopharynx and larynx, IMT SPET achieved a detection rate comparable to that of FDG PET. IMT SPET was clearly superior to MIBI SPET in this population. A further evaluation of the specificity of IMT in a larger number of patients appears justified.
Henze
Marcus
M
Department of Nuclear Medicine, University of Heidelberg, Germany. m.henze@dkfz-heidelberg.de
Mohammed
Ashour
A
Mier
Walter
W
Rudat
Volker
V
Dietz
Andreas
A
Nollert
Jörg
J
Eisenhut
Michael
M
Haberkorn
Uwe
U
D002277:Carcinoma / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D019805:alpha-Methyltyrosine
D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18; D019805:alpha-Methyltyrosine; D017256:Technetium Tc 99m Sestamibi