Final answer:
Annual training for diagnostic CT technologists includes radiation dose optimization and safe operation procedures, but does not typically include techniques for CT systems used for therapeutic radiation treatment.
Step-by-step explanation:
The answer to the question which of the following is not required as part of annual training for technologists who perform diagnostic computed tomography (CT) examinations is C. Techniques for CT systems used for therapeutic radiation treatment planning or delivery. Annual training for diagnostic CT technologists typically includes radiation dose optimization techniques, such as those addressed in Image Gently and Image Wisely campaigns (A), and safe procedures for the operation of the types of CT equipment used (B). These are essential for ensuring patient safety and the quality of diagnostic images. However, training related to therapeutic radiation treatment planning or delivery (C) is not typically required for diagnostic CT technologists, as it pertains to the use of CT in a therapeutic context rather than the diagnostic context.