Final answer:
To ensure the new collimator light bulb is properly aligned, you would perform a collimator test to confirm light to radiation field congruence.
Step-by-step explanation:
After changing the collimator light bulb, which is commonly a component of imaging equipment in the medical field, it's important to perform a quality control test to ensure proper alignment and functioning. The test you would perform is a collimator test or a field light to radiation field congruence test. This test will verify that the light field produced by the new bulb corresponds accurately to the X-ray field. It involves aligning a specific pattern or grid on the collimator with the light field and taking an X-ray to ensure the X-ray field matches the illuminated area. If there is misalignment, the collimator needs to be adjusted to prevent any discrepancies during actual medical imaging procedures.