Which statement about detector pixel size and spatial resolution is true?

Which statement about detector pixel size and spatial resolution is true?

• A. Detector pixel size has no effect on resolution.
• B. Fewer gray levels determine resolution.
• C. Detector pixel size sets the sampling grid; smaller pixels improve sampling resolution, but system blur and focal spot geometry also limit true resolution.
• D. Increasing dose always increases spatial resolution.

Answer: (C)

Pixel size defines how finely the image is sampled by the detector. Smaller detector pixels create a finer sampling grid, which can capture more detail. But the actual, or true, spatial resolution is also limited by blur from the imaging system—things like the focal spot geometry, geometric blur, and any motion or other unsharpness. So even with tiny pixels, large system blur will smear high-frequency details and prevent higher true resolution. The number of gray levels is about contrast resolution, not how finely space is sampled. Increasing dose reduces quantum noise, which can make edges look crisper, but it doesn’t change the sampling grid or the blur, so it doesn’t inherently raise true spatial resolution.

Pixel size defines how finely the image is sampled by the detector. Smaller detector pixels create a finer sampling grid, which can capture more detail. But the actual, or true, spatial resolution is also limited by blur from the imaging system—things like the focal spot geometry, geometric blur, and any motion or other unsharpness. So even with tiny pixels, large system blur will smear high-frequency details and prevent higher true resolution. The number of gray levels is about contrast resolution, not how finely space is sampled. Increasing dose reduces quantum noise, which can make edges look crisper, but it doesn’t change the sampling grid or the blur, so it doesn’t inherently raise true spatial resolution.