Infusion of drugs

An at least partly implantable system for injecting a substance into a patient's body, comprising

• at least one infusion needle disposed at least partly within at least one housing with a tip end of the at least one infusion needle arranged for penetrating the at least one housing's outer wall, the at least one housing being adapted for implantation inside a patient's body, and
• at least one drive unit adapted for implantation inside the patient's body, the at least one drive unit being coupled to the at least one infusion needle and arranged for advancing and retracting the tip end of the at least one infusion needle so that the at least one infusion needle penetrates, upon advancement of the tip end or ends thereof, said outer wall in at least one penetration area so as to allow for injecting the substance through said at least one penetration area via the at least one infusion needle, wherein the drive unit is configured to laterally displace the tip end of at least one of said at least one infusion needle in at least two different lateral directions, the drive unit being adapted to displace the infusion needle in at least a first lateral direction and back, and a second lateral direction and back, the second direction being different from the first direction, and the first and second lateral direction together allowing creation of a two-dimensional array of penetration sites to be obtained by means of a single one of said at least one needle in said at least one penetration area with at least one second number of said penetration sites being arranged above or below a first number of said penetration sites.