What is the minimum energy value of the CT x-ray beam?

The minimum energy value of the CT x-ray beam is correctly identified as 120 keV. This energy level is significant in computed tomography because it reflects the minimum level of photon energy necessary for effective imaging.

In CT imaging, x-ray beams are generated and pass through the body, with higher energy photons being more effective at penetrating tissues and providing clearer images. The selection of 120 keV is a standard setting in many CT machines because it balances image quality and patient dose, ensuring that the x-ray can traverse various types of tissues while still delivering adequate contrast for diagnostic purposes.

Using lower energy values, such as those in the 100 keV range, might not effectively penetrate denser tissues, leading to images with insufficient detail. On the other hand, using higher energy values, like 140 keV or 160 keV, could increase radiation exposure without significantly improving image quality beyond what can be achieved at 120 keV. The choice of 120 keV, therefore, represents a commonly accepted practice aimed at optimizing both safety and diagnostic efficacy in CT imaging.