Compared with CT, planar radiography doses are generally:

Compared with CT, planar radiography doses are generally:

• A. Higher
• B. Lower
• C. Similar
• D. Unknown

Answer: (B)

The key idea is how much energy is deposited in the body to create the image. Plain radiography uses a single, brief x-ray exposure in one projection, so the total energy delivered is relatively small. CT, on the other hand, rotates around the patient and collects hundreds of views to reconstruct cross-sectional images, often with higher tube current and longer cumulative exposure per slice. Even with modern dose-saving features, the overall amount of radiation from CT is much greater because you’re irradiating the patient through many angles and slices. For context, a typical single-view chest radiograph is on the order of hundredths of a millisievert, whereas a chest CT is usually several millisieverts. So, in general, planar radiography doses are lower than CT.

The key idea is how much energy is deposited in the body to create the image. Plain radiography uses a single, brief x-ray exposure in one projection, so the total energy delivered is relatively small. CT, on the other hand, rotates around the patient and collects hundreds of views to reconstruct cross-sectional images, often with higher tube current and longer cumulative exposure per slice. Even with modern dose-saving features, the overall amount of radiation from CT is much greater because you’re irradiating the patient through many angles and slices.

For context, a typical single-view chest radiograph is on the order of hundredths of a millisievert, whereas a chest CT is usually several millisieverts. So, in general, planar radiography doses are lower than CT.