Basms 2325

Athymic nude mice xenografted with BxPC3 tumors were injected with either ²²⁵Ac-DOTA-PEG₇-5B1 (18.5 kBq, 8.6 μg [MA = 308 kBq/nmol]; in 150 μL of 0.9 % NaCl + 1.0 % BSA) or ²²⁵Ac-DOTA-PEG₇-Tz (18.5 kBq, 0.4 nmol [MA = 46 kBq/nmol]; in 150 μL of 0.9 % NaCl + 1.0 % BSA) at 72 h post administration of 5B1-TCO (200 μg; in 200 μL of PBS). Mice were euthanized 1, 5, and 7 d post-injection of the radiopharmaceutical. Mouse kidneys and tumors were embedded and sectioned during the 20 minutes that followed the animal sacrifice. Kidney and tumor sections were placed in a film cassette against a phosphor imaging plate (Fujifilm BAS-MS2325) for a first exposure time of 1 hour at −20 °C. A second exposure (6 hours) with the same sections was performed once secular equilibrium was reached (24 h after first exposure). Kidney sections were later stained with hematoxylin and eosin for the differentiation of the cortex and medulla. Images analysis and quantification is described in Supporting Information.

Following radioactivity counting, aortas were placed in a film cassette against a phosphorimaging plate (BASMS-2325, Fujifilm, Valhalla, NY) for 24 hours at −20 °C in order to determine radioactivity distribution. The plates were read at a pixel resolution of 25μm with a Typhoon 7000IP plate reader (GE Healthcare, Pittsburgh, PA).