Question

An x-ray exposure of a particular part is made and restricted to a 14 × 17 in. field size. The same exposure is repeated, but the x-ray beam is restricted to a 4 × 4 in. field. Compared with the first image, the second image will demonstrate

1. less density
2. more contrast

Answer 1

The x-ray image with a 4 × 4 inch field will have less density and more contrast due to reduced scatter radiation, making it possible to distinguish between areas of different densities more clearly.

Step-by-step explanation:

When comparing two x-ray images where the x-ray exposure field sizes are different (14 × 17 inches and 4 × 4 inches), the image resulting from the smaller field size (4 × 4 inches) will demonstrate less density and more contrast. This happens because, with a smaller field size, there is less scatter radiation reaching the image receptor, which results in fewer x-ray photons being absorbed or deflected. As a result, areas of varying densities within the small field create distinct differences in image darkness and lightness, or contrast. The overall image density is also reduced because the lesser amount of scatter radiation contributes to the overall image formation.