What is the term for lowering the x-ray table's head by at least 15 degrees?

The term for lowering the x-ray table's head by at least 15 degrees is Trendelenburg. In this position, the patient's head is lower than their feet, which can be useful in certain medical scenarios, such as facilitating blood flow to vital organs or managing certain types of shock in patients. This technique can help to improve circulation and is often used during medical procedures to optimize patient safety and comfort.

The other options represent different positional techniques: the supine position refers to lying flat on the back, the seated position is simply sitting upright, and reverse Trendelenburg is when the table is tilted with the head elevated above the feet. While all these positions have their specific uses in radiographic procedures, Trendelenburg specifically describes the significant lowering of the head end of the table.