Intraoperative gamma probe localization of the ureters: a novel concept.
BACKGROUND
Ureteral stent placement to localize the ureters during operations is an invasive procedure. The aim of this study was to evaluate the feasibility of using the gamma probe to intraoperatively identify the ureters after intravenous injection of a radiopharmaceutical agent.


METHODS
Ten patients undergoing elective abdominal operations were prospectively enrolled in this study. An average dose of 4.5 mCi (range 2.8 to 5.3 mCi) of technetium Tc 99m-labeled diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) was administered intravenously before localization of the ureters. The gamma probe was used to localize the ureters. Correct identification of the ureters was confirmed when gentle manipulation induced a typical ureteral peristaltic pattern.


RESULTS
Gamma counts were significantly elevated in all ureters examined. Compared with background counts, gamma counts were increased over the ureter in all patients, with an average increase of 465%. The technique was modified after use in the first 3 patients and standardized for patients 4 through 10. Data from those seven patients were analyzed. Both ureters were correctly identified using the gamma probe at a mean of 15 minutes (median, 10 minutes) after a single (99m)Tc-DTPA injection (range 4 to 41 minutes). The mean background count was 80 counts per second (cps, range 50 to 130 cps). The mean ureter count was 393 cps (range 128 to 700 cps). The average percent increase of each ureter count compared with its specific background count was 465% (range 256% to 1,077%). The difference was statistically significant for all values (p < 0.001).


CONCLUSIONS
This novel technique of gamma probe localization of the ureters may offer a noninvasive approach for ureteral identification.
Berland
Todd L
TL
Department of Surgery, Mayo Clinic, Jacksonville, FL 32224, USA.
Smith
Stephen L
SL
Metzger
Philip P
PP
Nelson
Kevin L
KL
Fakhre
G Peter
GP
Chua
Heidi K
HK
Burnett
Omer L
OL
Falkensammer
Juergen
J
Hickman
Hollie J
HJ
Hinder
Ronald A
RA
D000005:Abdomen / Q000601:surgery*; D000328:Adult; D000368:Aged; D005240:Feasibility Studies; D005260:Female; D015902:Gamma Cameras; D006801:Humans; D007275:Injections, Intravenous; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage; D014513:Ureter / Q000000981:diagnostic imaging* / Q000293:injuries*; D014947:Wounds and Injuries / Q000517:prevention & control*
D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate