I copied this for you from the TSA web site I hope it helps:
Happy travels!
Colleen
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Travelers & Consumers Printable Version
Persons with Disabilities & Medical Conditions
Pacemaker, Defibrillator, Other Implanted Medical Devices, and Metal Implants
If you have implanted medical device, that you would like to remain private and confidential, ask the screener to please be discreet when assisting you through the screening process.
It is recommended (but not required) that individuals with a pacemaker carry a Pacemaker Identification Card (ID) when going through airport security. Show the screener your pacemaker ID, if you have one, and ask the screener to conduct a pat-down inspection rather than having you walk-through the metal detector or be handwanded.
It is recommended (but not required) that you advise the screener that you have an implanted pacemaker, other implanted medical device, or metal implant and where that implant is located.
Screener will offer you a private screening once it becomes known that you have a metal implant or implanted medical device.
If your Doctor has indicated that you should not go through the metal detector or be handwanded because it could affect the functionality of your device or the magnetic calibration of your device, or if you are concerned, ask the screener for a pat-down inspection instead.
Screeners will need to resolve all alarms associated with metal implants. Most alarms will be able to be resolved during a pat-down, therefore clothing will not be required to be removed or lifted as part of the inspection process.