Monitoring Use of Surgical Tools
There are two challenges with using RFID tags, one of which has been covered in the comments. 


The tag, presumably, must be autoclavable. 
As these tools are metal, the presence of a metal plane so close to the tag will cause problems, or completely prevent operation of normal RFID chips. 


As a possible solution, you could use the RFID tags manufactured by Xerafy which are specifically designed for this sort of application and are autoclavable. They implement RFID-on-metal (ROM), so they are designed for tagging metal objects such as surgical tools.  

A link to their brochure is here. 

There may be other suppliers in this market as well, but this should get you started. 

As well as tracking the use of tools, tracking surgical instruments could help prevent them from being misplaced (such as inside a patient).