A portable device (1) for the insertion of radioactive seeds in percutaneous interstitial brachytherapy applications, comprising: - an elongated main body (2) in the form of a handpiece - a shielded container (3) of radioactive seeds, received within said main body (2) and having a rotating drum (30) suitable, in use, to release one or more radioactive seeds at a time from the container (3) - means (4) for driving said rotating drum (30), activatable by an operator and based on lever mechanisms (41, 42) and gears (43, 44) and - means (7) for introducing one or more radioactive seeds in a body site of interest, comprising a substantially wire-shaped pusher (70), the overall arrangement being such that, in use, the pusher (70) urges the radioactive seed(s) released from said rotating drum (30) through a cannula unit (10), the latter connected, at one first proximal longitudinal end thereof, to said main body (2) and percutaneously inserted so that a distal longitudinal end thereof be arranged in the body site (Fig. 1).
