A method of manufacturing a core for casting a component (20) can include manufacturing a core for at least partially forming an internal passage architecture of a component with a material including radiopaque particles. A method can include removing a material including radio opaque particles from an internal passage architecture of a component; and inspecting the component via radiographic imaging at gamma/X-ray wavelengths to detect residual material. A core for use in casting an internal passage architecture of a component can include a material with radiopaque particles dispersed therein.