Seed position and geometric verification during surgery and follow-up in living animals were major issues in this study. For example, if the seeds are spaced irregularly, this may cause significant dose modifications that, in turn, may lead to under-detection or over-dosing, with the foreseeable consequences of inefficient treatment and the risks of complications. A preliminary analysis with an Advantage Workstation (GE, version 4.4, USA) was carried out in order to check the positioning of the plates and any seed migration. Then, the mesh coordinates were determined between the centroid of the plate and the bone anatomical landmarks to have the same mark on the two CT scans at D+15 (CT1) and D+180 (CT3) (Figure 4 ). The tolerance of a shift was set at 10 mm in all directions (X, Y, Z).
Finally, a dosimetric analysis was performed on VariSeedTM (Treatment Planning System, v8.0.2, Varian Medical Systems, Inc., Palo Alto, CA, USA) between CT1, CT2, and CT3. Seeds were detected automatically on each CT scan. Seed activity was fixed arbitrarily at 1 U (= 1 uGy.m2/h) or 0.787 mCi, to have a 160 Gy dose line around the mesh volume and 5 mm from the center of each seed (Figure 5 ).
Finally, a dosimetric analysis was performed on VariSeedTM (Treatment Planning System, v8.0.2, Varian Medical Systems, Inc., Palo Alto, CA, USA) between CT1, CT2, and CT3. Seeds were detected automatically on each CT scan. Seed activity was fixed arbitrarily at 1 U (= 1 uGy.m2/h) or 0.787 mCi, to have a 160 Gy dose line around the mesh volume and 5 mm from the center of each seed (