RT Journal Article
SR Electronic
T1 Improved Detection of Regional Melanoma Metastasis Using <sup>18</sup>F-6-Fluoro-<em>N</em>-[2-(Diethylamino)Ethyl] Pyridine-3-Carboxamide, a Melanin-Specific PET Probe, by Perilesional Administration
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 115
OP 122
DO 10.2967/jnumed.110.078154
VO 52
IS 1
A1 Delphine Denoyer
A1 Titaina Potdevin
A1 Peter Roselt
A1 Oliver C. Neels
A1 Laura Kirby
A1 Ivan Greguric
A1 Andrew Katsifis
A1 Donna S. Dorow
A1 Rodney J. Hicks
YR 2011
UL http://jnm.snmjournals.org/content/52/1/115.abstract
AB The efficacy of differing routes of administration of 18F-6-fluoro-N-[2-(diethylamino)ethyl] pyridine-3-carboxamide (18F-MEL050), a new benzamide-based PET radiotracer for imaging regional lymph node metastasis in melanoma, was assessed. Methods: B16-Black/6 metastatic melanoma cells harboring an mCherry transgene were implanted into the left-upper-foot surface of 49 C57 Black/6 mice as a model of popliteal lymph node (PLN) metastasis. Ultrasound scanning of the left PLN was performed at baseline and in combination with 18F-MEL050 PET on days 5, 9, and 14. Mice were divided into 2 groups to compare the results of tracer administration either subcutaneously at the tumor site (local) or in the lateral tail vein (systemic). After PET on each imaging day, 5 mice per group—including any with evidence of metastasis—were sacrificed for ex vivo validation studies including assessment of retained radioactivity and presence of the mCherry transgene as a surrogate of nodal tumor burden. Results: Nine mice were judged as positive for PLN metastasis by ultrasound at day 5, and 8 PLNs were positive on 18F-MEL050 PET, 3 after systemic and 5 after local administration. Ex vivo analysis showed that ultrasound correctly identified 90% of positive PLNs, with 1 false-positive. 18F-MEL050 PET correctly identified 60% of positive PLNs after systemic administration and 100% after local administration with no false-positive results by either route. The average node-to-background ratio for positive PLNs was 6.8 in the systemic-administration group and correlated with disease burden. In the local-administration group, the mean uptake ratio was 48, without clear relation to metastatic burden. Additional sites of metastatic disease were also correctly identified by 18F-MEL050 PET. Conclusion: In addition to its potential for systemic staging, perilesional administration of 18F-MEL050 may allow sensitive and specific, noninvasive identification of regional lymph node metastasis in pigmented malignant melanomas.