How long the lymphoscintigraphy imaging should be continued for sentinel lymph node mapping?
OBJECTIVE
We assessed the need for delayed lymphoscintigraphy imaging for sentinel lymph node (SLN) biopsy in stage I and II breast cancer patients using intradermal injection of (99m)Tc-antimony sulfide colloid.


METHODS
Seventy-five patients with early-stage breast cancer were included in our study. Periareolar intradermal injections of 0.5 mCi/0.2 mL (99m)Tc-antimony sulfide colloid was used for the patients without previous excisional biopsy (45 patients). Two intradermal injection of 0.5 mCi/0.2 mL (99m)Tc-antimony sulfide colloid was used on each side of the dermal incision in patients with the history of excisional biopsy (30 patients). Anterior and lateral static images were taken at 2 min. If SLN was not visualized, delayed imaging at 5, 10, 30, 60, 90, 150, and 180 min was done (till the visualization of the SLN or 180 min). SLN was performed by the combination of gamma probe and blue dye during surgery.


RESULTS
Sentinel lymph node detection rate was 96% (72/75). SLNs were detected on the immediate (2 min) images in 55 (73.33%) patients. In the remaining patients, the SLNs were detected first on the 5-, 10-, and 30-min images in 10 (13/33%), 5 (6.66%), and 2 (2.66%) patients, respectively. In three patients (4%), SLN was not detected by lymphoscintigraphy even on 180-min images. During surgery, SLN was not detected in these three patients either.


CONCLUSIONS
Considering the rapid flow of (99m)Tc-antimony sulfide colloid in our study, lymphoscintigraphy imaging can be completed in the nuclear medicine department without any delay in sending the patient back to the surgery department. Thirty minutes after radiotracer injection seems to be the optimal time for lymphoscintigraphy and delayed imaging beyond 30 min would not be necessary.
Sadeghi
Ramin
R
Department of Nuclear Medicine, Imam Reza Hospital, Mashhad University of Medical Sciences, 91379-13316 Mashhad, Iran.
Forghani
Mohammad Naser
MN
Memar
Bahram
B
Rajabi Mashhadi
Mohammad Taghi
MT
Dabbagh Kakhki
Vahid Reza
VR
Abdollahi
Abbas
A
Zakavi
Seyed Rasoul
SR
D000328:Adult; D000965:Antimony; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D009367:Neoplasm Staging; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy; D017556:Technetium Compounds; D013997:Time Factors
D019275:Radiopharmaceuticals; D017556:Technetium Compounds; C019096:technetium Tc 99m antimony sulfide; D000965:Antimony