Localization of small-cell lung cancer xenografts with iodine-125-, indium-111-, and rhenium-188-somatostatin analogs.
We examined the potential of radiolabeled somatostatin analogs, 125I-Tyr-3-octreotide (125I-octreotide), (111)In-DTPA(diethylenetriaminepentaacetatic acid)-D-Phe-1-octreotide (111In-octreotide), and 188Re-octreotide for targeting small-cell lung cancer (SCLC) in a mouse model. Tyr-3-octreotide was labeled with 125I by the chloramine T method, and (111)In-octreotide was obtained as a kit, while 188Re was eluted from a 188W/188Re generator, and octreotide was directly labeled with 188Re by reducing disulfide bonds. The 125I-, 111In-, and 188Re-octreotides were injected i.v. into athymic mice bearing NCI-H69 tumors, and the biodistributions were determined at 15 min, and 2, 4, 8, and 24 h. Tumor uptakes were 0.5+/-0.2, 0.3+/-0.1, 0.3+/-0.1 %ID/g, and tumor-to-blood ratios were 1.8, 11.9, 1.2 at 8 h for 125I-, 111In-, and 188Re-octreotides, respectively. Accumulations of 111In-octreotide in normal tissues were lower than those of 125I- and 188Re-octreotides. 188Re-octreotide can be used to localize SCLC lesions as efficiently as radioiodinated octreotide. However, 111In-octreotide was the most suitable agent to obtain high tumor-to-normal tissue contrast for localizing SCLC.
Hosono
M
M
Department of Radiology, Saitama Medical Center, Saitama Medical School, Kawagoe.
Hosono
M N
MN
Haberberger
T
T
Zamora
P O
PO
Guhlke
S
S
Bender
H
H
Knapp
F F
FF
Biersack
H J
HJ
D000818:Animals; D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging* / Q000378:metabolism*; D007205:Indium Radioisotopes / Q000493:pharmacokinetics*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics*; D007553:Isotope Labeling; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D011868:Radioisotopes; D011877:Radionuclide Imaging; D012211:Rhenium / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D011868:Radioisotopes; D012211:Rhenium; D015282:Octreotide