Whole-body lymphoscintigraphy using transmission scans.
OBJECTIVE
Our objective was to show the advantages of performing whole-body lymphoscintigraphy using transmission sources. This technique should decrease scanning time, help locate the sentinel lymph node, and decrease radiation exposure to the technologist.


METHODS
Twenty patients with proven melanoma received 18.5 MBq (0.5 mCi) filtered (0.22 microm) (99m)Tc-sulfur colloid in a 0.2-mL volume, administered as multiple intradermal or subcutaneous injections around the known melanoma lesion or scar. All 20 patients underwent serial static imaging immediately after the injection, along with whole-body scanning after the static imaging. The static emission images were acquired for 5 min and the transmission images for 1 min using a 256 x 256 matrix. The whole-body transmission scans were acquired after the whole-body emission scans. The transmission scans were obtained with the same parameters as the emission scans, with the addition of placement of a (57)Co sheet source on one of the detectors of the large-field-of-view dual-head camera. The planar static axial images (transmission, emission) were compared with the whole-body images (transmission, emission) to determine whether the same number of lymph nodes was visualized with each technique. Posterior outlines were obtained through computer manipulation of anterior transmission images.


RESULTS
In all 20 patients, the number of lymph nodes seen on the static images was the same as that seen on the whole-body emission and transmission images. The whole-body emission and transmission scanning time was an average of 30 min less than the time required to acquire the serial static images.


CONCLUSIONS
The anatomic location of the sentinel lymph node is seen more easily on whole-body images, both anterior transmission and posterior transmission, than on planar static images. Whole-body emission and transmission imaging decreased scanning time and thus improved patient comfort and throughput. Technologists received less radiation exposure when handling the (57)Co source only twice during whole-body imaging, as opposed to several times during static imaging.
Vallejo Mar
Martha
M
Department of Nuclear Medicine, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA. mmar@di.mdacc.tmc.edu
Gee-Johnson
Sonia
S
Kim
E Edmund
EE
Podoloff
Donald A
DA
D006801:Humans; D008207:Lymphatic Metastasis; D061305:Lymphoscintigraphy; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000556:secondary; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000000981:diagnostic imaging*; D013671:Technetium Tc 99m Sulfur Colloid
D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid