Which of the following describes the factors of the image receptor that influence spatial resolution?

• A. size, pitch, & number of pixels
• B. size, pitch, & number of detector elements (dexel)
• C. shape, pitch, & number of pixels
• D. shape, pitch, & number of detector elements (dexel)

Answer: (B)

Spatial resolution on an image receptor is determined by how finely the image is sampled by the detector grid. The three key factors are the size of each detector element (the pixel size), the pitch—the center-to-center distance between adjacent detector elements—and the total number of detector elements across the active area (dexels). Smaller detector-element size provides more samples per unit area, allowing finer detail to be captured. A smaller pitch means the samples are closer together, increasing sampling density and improving the ability to distinguish nearby structures. More detector elements across the field gives a denser sampling grid, boosting resolution as long as the system can handle the data and dose considerations. Shape isn’t a primary determinant in this context, and using terms like pixels instead of dexels can blur whether we’re talking about the detector’s sampling elements versus the display image.