How do radioisotopes help inspect metal parts for internal defects?

Radioisotopes are used to inspect metal parts for internal defects primarily through gamma-ray techniques, a form of nondestructive testing.

In this process, radiation from a radioisotope source is directed to pass through the material being inspected. As the radiation travels through the metal, it impinges upon a photographic film placed on the opposite side. Because internal flaws or defects in the metal affect how the radiation passes through, they create distinct patterns on the film, allowing for the identification and location of structural issues.1

While radioisotopes are essential for this type of radiographic inspection, it is important to note that other methods, such as ultrasonic testing, are also used to detect internal faults like cracks or corrosion by measuring how sound waves reflect off internal structures.2