A diagnostic imaging apparatus generates a three-dimensional diagnostic image representation. After a job is received, a determination is made as whether the received job is a \u201cshort-lived job\u201d or a \u201clong-lived job. The initiation flaw is formed by a mechanical scoring head which is carried by moving carriage and which undergoes retrograde motion relative to the carriage so as to increase the time available for forming the initiation flaw. The processing module then identifies a codebook entry from the one of the plurality of codebooks based on the desired digital signal component to produce a selected codebook entry. An adhesive is disposed in an annular space defined by the interior surface of the bore and an exterior surface of the shaft portion.