Which of the following projections would NOT take advantage of the so-called "heel effect" if the cathode was toward the feet?

The heel effect is a phenomenon in radiography where the intensity of the x-ray beam is greater on the side of the cathode (the negative terminal of the X-ray tube) compared to the anode (the positive terminal). This effect is utilized particularly in projections where there is a significant difference in tissue thickness or density along the path of the x-ray beam, allowing for more uniform exposure.

In the case of a lateral femur projection with the cathode toward the feet, the thicker part of the femur would be closer to the anode, which is not located directly opposite the cathode. This positioning does not utilize the heel effect effectively since the thicker, denser area of the anatomy is not aligned with the area of higher exposure. Therefore, the exposure would not be optimized, making this projection less advantageous for utilizing the heel effect.

On the other hand, projections like the AP thoracic spine, AP lumbar spine, and lateral lumbar spine can potentially utilize the heel effect as they take advantage of the varying thickness of the spine along the beam path, allowing better image quality and exposure due to the positioning of the cathode. This highlights how specific projection techniques can either benefit from or overlook the heel effect based on their anatomical relationship with the