Hi, I am looking for a sensor/ detector (A) which could perform the following: constrain: transmitter/ receiver (B) size must be small so that it can be inserted in human bone to be detected later, diameter 3mm X 6mm length is preferred, however, a bigger size can be consider as well. Application: once this (B) in inserted into human bone, imagine the size of bone as diameter 16mm X 300mm length cylinder (C) with wall thickness 3mm covered by tissue, muscle. I will need a detector (A) at close range, preferably a handheld type which I can scan from any part outside the body through skin, muscle, tissue and bone of arms/ leg (C) to detect the location of (B), this detector (A) will tells me the X,Y,Z distance from a reference. Once I can pinpoint the location, I can retrieve the (B). ultrasound may not be applicable as there may be interference with the bone as solid material. perhaps some kind of Rf system may work? someone please advise?