Gallium-68-labeled DOTA-rhenium-cyclized alpha-melanocyte-stimulating hormone analog for imaging of malignant melanoma.
BACKGROUND
Diagnosis of malignant melanoma is critical, since a patient's prognosis is poor. Previous studies have shown that 64Cu- and 86Y-DOTA-ReCCMSH(Arg11) have the potential for early detection of malignant melanoma by exploiting the sensitivity and high resolution of positron emission tomography (PET). This encouraged us to investigate DOTA-ReCCMSH(Arg11) labeled with another beta+-emitting radionuclide, 68Ga.


METHODS
DOTA-ReCCMSH(Arg11) was successfully labeled with 68Ga at pH 3.8-4 at 85 degrees C. Acute biodistribution and small-animal PET imaging studies were performed in mice bearing B16/F1 melanoma tumor.


RESULTS
Biodistribution studies showed moderate receptor-mediated tumor uptake, fast nontarget organ clearance and high tumor to nontarget tissue ratios. Preadministration of d-lysine significantly reduced kidney uptake without affecting the uptake of the agent in the tumor. Small-animal PET images showed that the tumor could be clearly visualized at all time points examined (0.5-2 h) with the standardized uptake value analysis following a similar trend as the biodistribution data.


CONCLUSIONS
The preliminary data obtained suggest that 68Ga-DOTA-ReCCMSH(Arg11) is a promising PET imaging agent for early detection of malignant melanoma.
Wei
Lihui
L
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Miao
Yubin
Y
Gallazzi
Fabio
F
Quinn
Thomas P
TP
Welch
Michael J
MJ
Vāvere
Amy L
AL
Lewis
Jason S
JS
D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D007553:Isotope Labeling / Q000379:methods; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D051379:Mice; D008810:Mice, Inbred C57BL; D009928:Organ Specificity; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution; D000521:alpha-MSH / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
C526995:68Ga-1,4,7,10-tetraazacyclododecane 1,4,7,10-tetraacetic acid (ReO-acetyl(Cys(3,4,10),Phe(7),Arg(7))aplha-MSH(3-13)); D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D000521:alpha-MSH