Fig. 1

Study design. a Imaging study. Animals underwent a baseline [¹⁸F]HX4 small-animal PET (μPET) scan and were rescanned 30 min after metformin or saline administration 24 h later (i.e., follow-up scan). Two days later, animals were given therapy or sham and tumor volume was followed until a volume of 1500 mm³ was reached. b Detail of the [¹⁸F]HX4 μPET/CT scan protocol. c Overview of the different therapy groups. d Histology study. Animals were sacrificed at different points in time for ex vivo validations of baseline and early post-therapy parameters. MET, metformin; RT, radiotherapy; SAL, saline