A method for the assisted manipulation of an instrument in an assistive assembly for instrument manipulation, comprising: a medical imaging system comprising a support to immobilize at least one part of a patient intended to be imaged or already imaged by said system, an assistive device for assisted manipulation of an instrument intended to be used in said patient, said device comprising: a mobile mechanical structure operable by an operator, on which at least one instrument can be fixed, said method being characterized in that it comprises the step to calibrate the position of the assistive device relative to the position of the imaging system, thereby allowing the position of the patient part to be known within a reference frame related to the assistive device, to assist the operator in manipulating the instrument in the patient.
