Why do items detected by X-ray machines present images of different colors

X-ray machine detection equipment is an imaging system that can generate digital radiation images. Its purpose is to convert detailed image information that cannot be seen by the naked eye into visible images. It mainly includes radiation sources, radiation detectors, data acquisition and transmission equipment, and image processing equipment.

The penetration ability of X-rays is related to material density, size, and composition. High material density, more absorption of X-rays and less transmission; Low density, less absorption, and more transmission. Thicker objects are less likely to penetrate, and objects with higher effective atomic numbers are less likely to penetrate. The penetration power of X-rays varies for different objects, so there are differences in the color of imaging. X-ray machine detection equipment is based on the differences in the absorption characteristics of X-rays by objects. By detecting the effective atomic number of objects, and based on its own image processing function and color configuration scheme, it presents X-ray images of objects.

Therefore, we classify the images of X-ray machine detection equipment into three categories based on the different materials of the items: orange, green, and blue. Orange represents light elements with effective atomic numbers less than 10 and their organic compounds, such as food and water. Green generally represents medium mass elements with effective atomic numbers of 10-18, such as sodium, potassium, sulfur, phosphorus, etc. Blue represents heavy metals with effective atomic numbers above 18, such as iron, zinc, nickel, etc. However, in practical applications, objects generally appear in a mixed and stacked state, with different sizes and significant differences in their absorption characteristics of X-rays. However, the above rules are not strictly followed.