The invention relies on a medical device for an intracorporeal location, wherein: it comprises a deformable armature, at least partially made of a shape memory material and having an Ea end and an Eb end, said Ea end being larger than said Eb end, it has an essentially triangular, trapezoidal, ovally or diamond-shaped, the sides of which extending between said Eb end and the corners of said Ea end, said deformable armature includes a middle rip extending from said Ea end to said Eb end and multiple cross elements extending between the middle rip and said sides, wherein said sides are formed by sides braces, it comprises at least one x-ray visible marker fixed at the deformable armature selected from the group consisting of gold, silver, platinum, tantalum, tungsten, niobium, palladium, iridium, it comprises a guide suited for the intracorporeal introduction of said medical device, and an extraction holder of the medical device. The invention also relies on a device for the introduction, by an endoscopic or percutaneous way, of the medical device, and on a method for accurately targeting a target area during radiation treatment through image guidance comprising determining the location of the medical device in real time using at least one method of targeting selected from the group consisting of lasers, visual, infrared, MRUMRS, RF and radiation； and modifying the radiation treatment beam path to adaptively compensate for a change in position of the target area.
