i was recently reading on a refiners website that the catheters are plated in pt. catheters, are naturally thrown out as a bio hazard. i believe you would have to get ahold of someone at the hospital, custodial manager perhaps, to find out where the waste is going, and how you could acquire the contract for disposal. hospitals wont give you any waste without a written contract as it would become legally binding on their end, if something diverse occured. most hospitals and outpatient clinics likely pay a service for disposal. if you could get ahold of the right people at the hospital, i'm certain they would be extremely interested in "free" disposal.
also , i believe x-ray film, which is eventually thrown out, contains ag, rh, perhaps traces of pt.