Fig. 6.

SPECT-CT images (single slice) after unmixing for high energy window for ¹¹¹In detection (170–250 keV) and for low energy window consisting of primarily ¹²⁵I activity (20–40 keV), collected at 4 h after injection of [¹¹¹In]–[¹²⁵I]LS734. a, b ¹¹¹In window: higher activity was detected in the treated tumor (T) than the saline control treated tumor (C). The kidneys (K) had highest signal followed by the liver (L) indicating fast clearance of the ¹¹¹In labeled probe and fragments. c, d ¹²⁵I window: activity was detected in both tumors, presumably preferential retention of the lipophilic fragment although activity gastrointestinal tract (GI) and thyroid glands indicates partial physiological deiodination, most likely a function of normal as well as tumor mediated. Therefore, reported SUV values for ¹²⁵I include peptide-bound and free fractions. High activity in the liver and GI indicates hepatobiliary clearance of the lipophilic ¹²⁵I fragments.