Final answer:
In routine wrist projections, collimate to include the distal radius, the distal ulna, and the carpal bones, adjusting for patient size and ensuring proper coverage for conditions such as a Colles fracture.
Step-by-step explanation:
When performing routine wrist projections, the area you should collimate to include depends on the specific projection. However, as a general rule, you should include the distal radius, the distal ulna, and the carpal bones in their entirety. The purpose of collimation is to reduce the patient's exposure to radiation by restricting the X-ray beam to only the area of interest, and it helps to improve image contrast by reducing scatter radiation.
For a PA wrist projection, align the X-ray beam perpendicular to the mid-carpal area. For a lateral wrist projection, the beam should be perpendicular to the frontal plane through the distal radius and ulna. In cases where specific injuries or conditions are suspected, such as a Colles fracture, additional oblique views or focused projections might be required. Remember to adjust collimation according to the patient's size and the area being imaged to ensure diagnostic quality while maintaining ALARA (As Low As Reasonably Achievable) principles for radiation dose.