What does the absorption of x-rays depend on?

The absorption of x-rays is primarily influenced by the density and atomic number of the tissue being imaged. In x-ray imaging, tissues with a higher atomic number, such as bone, absorb more x-rays compared to softer tissues like muscle or fat. This is because heavier elements have more electrons that can interact with the x-rays, resulting in increased absorption.

Additionally, the density of the tissue plays a crucial role. Denser tissues contain more mass per unit volume, which contributes to a greater number of interactions between the x-rays and the tissue atoms. Thus, when higher density and atomic number materials are present, they will appear whiter or more radiopaque on the radiograph, while less dense tissues will appear darker or more radiolucent.

The options relating to energy of the x-ray photons and thickness of the material may influence the overall image quality and the amount of radiation exposure, but they do not primarily determine the fundamental concept of x-ray absorption as effectively as the density and atomic number do.