[[(18)F]N-(4'-fluorobenzyl)-4-(3-bromophenyl) acetamide for imaging the sigma receptor status of tumors: comparison with [(18)F]FDG, and [(125)I]IUDR.
A series of biodistribution studies were conducted with the radiotracer, [(18)F]N-(4'-fluorobenzyl)-4-(3-bromophenyl)acetamide, [(18)F]1 in nude mice bearing tumor xenografts of the mouse mammary adenocarcinoma, line 66. This radiotracer has a high affinity for both sigma(1) and sigma(2) receptors. In vivo studies were also conducted in order to assess the effect of blocking sigma(1) receptors on tumor uptake and the tumor:background ratio of this radiotracer. The results of these studies revealed that blocking the sigma(1) receptor so that only the sigma(2) receptors are labeled in vivo, results in a higher tumor:background ratio with only a small reduction in the tumor uptake of the radiotracer relative to the no-carrier-added (i.e., nonselective) conditions. Comparative in vivo studies were also conducted with the anatomic and metabolic imaging agent, [(18)F]FDG, and a radiolabeled DNA precursor, [(125)I]IUdR. Both of these radiolabeled compounds represent classes of agents that have been proposed for imaging the proliferative status of solid tumors. The results of these studies indicated that a sigma(2)-selective imaging agent may be, 1) a better anatomic imaging agent for breast cancer than [(18)F]FDG, and 2) a better functional imaging agent than the radiolabeled DNA precursors, [(123/124)I]IUdR and [(11)C]thymidine, for measuring the proliferative status of breast tumors with PET and SPECT. However, additional studies will be needed to compare sigma(2)-selective imaging agents with [(18)F]FLT in order to determine which is the more appropriate imaging agent for measuring the proliferative status of breast tumors with PET.
Mach
R H
RH
Department of Radiology-PET Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Huang
Y
Y
Buchheimer
N
N
Kuhner
R
R
Wu
L
L
Morton
T E
TE
Wang
L
L
Ehrenkaufer
R L
RL
Wallen
C A
CA
Wheeler
K T
KT
D000081:Acetamides / Q000138:chemical synthesis*; D000230:Adenocarcinoma / Q000000981:diagnostic imaging; D000818:Animals; D005260:Female; D019788:Fluorodeoxyglucose F18; D007065:Idoxuridine; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging; D051379:Mice; D008819:Mice, Nude; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D017480:Receptors, sigma / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014018:Tissue Distribution
D000081:Acetamides; C434767:N-(4'-fluorobenzyl)-4-(3-bromophenyl)acetamide; D019275:Radiopharmaceuticals; D017480:Receptors, sigma; D019788:Fluorodeoxyglucose F18; D007065:Idoxuridine