Chakera AH, Hölmich LR, Schoedt M, et al. - Patients having sentinel node (SN) biopsy for melanoma the day after lymphoscintigraphy using Tc99m-nanocolloid are reported to have worse survival outcome than that of patients having lymphoscintigraphy and SN biopsy on the same day. Overnight migration of the tracer from SNs to 2nd-tier nodes occurs, causing failure to remove true SNs, might be a possible explanation for aforementioned condition. In order to check if onward migration of colloid from previously-identified SNs had occurred, researchers here investigated the possibility of overnight tracer migration resulting in errors in SN-identification in 12 patients scheduled for lymphoscintigraphy the day before surgery by repeating SPECT/CT imaging the next morning, prior to their SN biopsy. Findings here did not indicate any migration of nanocolloid overnight, hence this cannot explain the reported survival disadvantage for patients undergoing SN biopsy the day after lymphoscintigraphy. A likely alternative possibility is that for next-day procedures, use of inadequate doses of radioisotope would have been made, causing the mistaken removal of 2nd-tier nodes instead of true SNs more frequently.