GRPR and cancer: Combined treatment with everolimus and [<sup>47</sup>Sc]Sc-LF1 in PC3-mice, significantly inhibited tumor growth compared to monotherapies.<h4>Conclusion</h4>The high tumor uptake in two cancer entities with elevated expression of GRPR and the tumor response (tumor size and survival rate) highlight the significant theranostic potential of [<sup>44</sup>Sc]Sc/[<sup>47</sup>Sc]Sc-LF1 for PET (scandium-44) and SPECT (scandium-47) imaging and radionuclide targeted therapy.