*2.2. Imaging Procedures*

According to the standard of care, patients underwent mammography, ultrasound and MRI of the breast and axilla for locoregional staging. Patients at VUmc underwent an additional diagnostic CT scan of the thorax/abdomen and at both centers bone scans were performed if indicated (i.e., 'conventional imaging'). FDG PET scans were performed using Gemini TF-64 or Ingenuity TF-64 PET/CT scanner at VUmc and Gemini TF-16 or Gemini TF-Big Bore 16 (Philips Medical Systems, Cleveland, Ohio, United States of America) at AvL, according to the guidelines of the European Association of Nuclear Medicine (EANM) [26]. Patients were administered 3.5 MBq/kg FDG at VUmc, and 190–240 MBq (according to the body mass index) at AvL [26]. All patients underwent a low-dose CT scan for attenuation correction, followed by the PET scan (skull vertex to mid-thigh) at 60 min post-injection, with 2 min per bed position.
