Library · Test
Bone radiography
Make it clearer
A bone X-ray sends a small amount of radiation through the body and captures a still image, either on film or on a digital receptor, the electronic plate that can be used in place of film.
What makes the image possible is that each tissue absorbs radiation differently. How much it absorbs depends on its density and on its atomic number, the number of protons in the nucleus of its atoms. That difference is called differential absorption, and from it comes contrast, the difference between light and dark. It is a cast shadow: whatever stops more of the beam appears lighter.
That is where the gray scale you see comes from. Bone absorbs the most and looks white; air absorbs the least, which is why areas like the lungs look black. Looking for fractures, that is, broken bones, is a common use of this study.
In brief
Radiography sends a small amount of radiation through the body and captures a still image on film or on a digital receptor.
Each tissue absorbs radiation differently depending on its atomic number and its density, and that differential absorption is what creates the image's contrast.
A cast shadow: whatever stops more of the beam is drawn lighter.
That is why bone, which absorbs the most, looks white, and the air in the lung, which absorbs the least, looks black; the study is commonly used to look for fractures.
Sources (2)
- MedlinePlus, U.S. National Library of MedicineX-Rays, MedlinePlusPublished
- National Center for Biotechnology Information, StatPearls PublishingX-ray Image Acquisition, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated