5. Injection. The injection must be very slow. An injection rate of 1 ml of the contrast agent - DC Bead suspension per minute is recommended. Thus, it takes 10-20 minutes to infusion 1 vial of DC bead. Care should be taken to avoid sedimentation of the beads in the syringe by rotating the syringes or using a 3-way stopcock to gently suspend the beads in the solution.