Enhanced uptake of [11C]TPMP in canine brain tumor: a PET study.
In vitro studies have demonstrated the membrane potential-dependent enhanced uptake of phosphonium salts, including [3H]triphenylmethylphosphonium (TPMP), into mitochondria of carcinoma and glioma-derived tumor cells, suggesting the potential use of phosphonium salts as tracers for tumor imaging. This study characterizes the in vivo uptake of [11C]TPMP in canine brain glioma using PET.


METHODS
Dynamic paired PET studies of [11C]TPMP followed by [68Ga]ethylenediaminetetraacetic acid (EDTA) were performed 4 d before and 9 d after tumor cell inoculation. Graphical analysis was used to evaluate [11C]TPMP retention in tumor tissue. Distribution of tracer uptake was compared with tumor histological sections.


RESULTS
[11C]TPMP exhibited enhanced uptake and prolonged retention in tumor cells. Patlak plot was linear over the 20- to 95-min postinjection period (r = 0.97 +/- 0.1). [68Ga]EDTA exhibited a gradual washout from the tumor tissue. The tumor-to-normal brain uptake ratio at 55 to 95 min postinjection was 47.5 for [11C]TPMP and 8.1 for [68Ga]EDTA. Qualitative comparison with histological sections indicated that [11C]TPMP enhanced uptake was restricted to the tumor area.


CONCLUSIONS
The enhanced uptake and prolonged retention in tumor suggest [11C]TPMP as a promising means for imaging of gliomas in dogs. The need for studies in humans is indicated.
Madar
I
I
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21282-0855, USA.
Anderson
J H
JH
Szabo
Z
Z
Scheffel
U
U
Kao
P F
PF
Ravert
H T
HT
Dannals
R F
RF
D000818:Animals; D001932:Brain Neoplasms / Q000000981:diagnostic imaging*; D002250:Carbon Radioisotopes; D004285:Dogs; D004492:Edetic Acid; D005710:Gallium Radioisotopes; D018316:Gliosarcoma / Q000000981:diagnostic imaging*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009861:Onium Compounds; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed; D014320:Triphenylmethyl Compounds
D002250:Carbon Radioisotopes; D005710:Gallium Radioisotopes; D009861:Onium Compounds; D019275:Radiopharmaceuticals; D014320:Triphenylmethyl Compounds; C011561:triphenylmethylphosphonium; D004492:Edetic Acid