What is a problem associated with beam hardening in x-ray imaging?

• A. Lower image quality with increased body thickness
• B. Increased proportion of high energy x-rays with body thickness
• C. Decreased patient radiation exposure
• D. Inconsistency in exposure time

Answer: (B)

Beam hardening is a phenomenon that occurs during x-ray imaging, resulting in the alteration of the x-ray beam as it passes through different tissues. It refers to the process where lower energy x-rays are absorbed more than higher energy x-rays as they penetrate through denser materials, such as bone or an increased thickness of soft tissue. As a result, the x-ray beam becomes "harder," meaning it has a higher average energy.

The correct answer highlights that with greater body thickness, there is an increased proportion of high-energy x-rays that reach the detector. This is because, during beam hardening, the less penetrating, lower energy x-rays are filtered out, leading to a beam predominantly composed of more penetrating, higher energy x-rays. This shift can cause various artifacts in the resulting images, impacting their diagnostic quality since the attenuation of different tissues and structures may not be accurately represented.

Recognizing the behavior of x-rays as they interact with varying body thickness is crucial for understanding the implications on image quality and interpretation in bone densitometry. This principle is essential, especially in clinical settings, as it underscores the need for adjustments in imaging protocols to counteract the effects of beam hardening.