Nowhere is the need for material integrity more obvious than in medical devices that are implanted into human beings. A failed device inside an aircraft or power plant may, under some circumstances, cause a problem. A failed device inside a human being will always cause a problem. Therefore, assuring the integrity of the materials used for manufacturing implanted medical devices and the actual medical devices themselves is extremely important.
Nondestructive testing (NDT) is commonly used to detect defects in material without damaging the material or making it unsuitable for use. NDT contains a variety of methods which can detect defects open to the material surface and contained within the material itself (subsurface). Detecting these defects in medical devices before they are implanted is critical to ensure the safety and reliability of such devices. Two common methods used are liquid penetrant testing (PT) and ultrasonic testing (UT).