Final answer:
To increase spatial resolution in X-ray imaging, one must increase the Source-to-Image Distance (SID) and decrease the focal spot size. Increasing the Object-to-Image Distance (OID) decreases spatial resolution, so the correct answer is b. 1 and 3 only.
Step-by-step explanation:
Spatial resolution is a term often used in imaging sciences to describe the ability of a system to visualize small details distinctly. In the context of X-ray imaging, which the question likely pertains to, there are specific factors that can affect spatial resolution:
- Increase in SID (Source-to-Image Distance): A greater SID reduces magnification and improves image sharpness by reducing the penumbra effect (the blurry edge seen around an image).
- Decrease in OID (Object-to-Image Distance): A smaller OID minimizes the penumbra effect like a larger SID does, thus increasing spatial resolution.
- Decrease in focal spot size: A smaller focal spot helps in producing a sharper image because the X-rays come from a more precise point, reducing the blur in the image produced.
Therefore, the answer to the question is b. 1 and 3 only. Increasing SID and decreasing the focal spot size will increase spatial resolution, while increasing OID actually decreases spatial resolution.