The invention relates to a system (10) for providing an object (2) in a body (1), a processor (18) arranged to be used in the system (10) for providing an object (2) in a body(1), an instrument (12) for providing an object (2) into a body (1), a method for detecting a providing of an object (2) in a body (1) and a software product for detecting a providing of an object (2) in a body (1). In order to allow for a providing of an object (2) in a body (1) and a detecting thereof while avoiding the drawbacks on the known approaches, e.g. giving an opportunity for reliable localization in ultrasound images used for real-time monitoring of a medical procedure with reduced error proneness to electromagnetic interference, the invention utilizes the finding that the characteristics of a reception or transmission of an ultrasound transducer (24, 26) are influenced by the surrounding environment of the ultrasound transducer (24, 26). By detecting changes in the characteristics the presence or absence of an object (2) to be provided at the ultrasound transducer (24, 26) is determined.