*2.5. Mouse Experiments*

All *in-vivo* animal experiments were performed in full compliance with the institutional guidelines of the Helmholtz Center Munich and with approval by the Government District of Upper Bavaria. Hairless NOD.SCID mice (Envigo, Rossdorf, Germany) were anesthetized with isoflurane. For both imaging systems, a custom-made holder was used to vertically fix the mice in a stationary position with fore and hind paws attached to the holder during the experiments. The mice were immersed inside the water tank with the animal head being kept above water. The temperature of the water tank was maintained at 34 ◦C with a feedback controlled heating stick. A breathing mask with a mouth clamp was used to fix the head in an upright position and to supply anesthesia and oxygen. During measurement, the anesthesia level was kept at ~2% isoflurane.
