ARRT Practice Exam 2025: Complete Preparation Guide

The primary purpose of a grid in radiography is to reduce scatter radiation. When X-rays pass through the body, some of them are scattered due to interactions with tissues, which can degrade the quality of the radiographic image. Scatter radiation does not contribute to the useful image information but instead adds unwanted density, resulting in a fogged or unclear image.

Grids are placed between the patient and the imaging receptor, containing a series of thin lead strips that allow primary radiation to pass through while absorbing scattered radiation. This selective absorption helps enhance the contrast of the image by ensuring that only the X-rays that have traveled in a straight line from the source to the detector are recorded.

The other options provided do not accurately reflect the role of grids in radiography. Enhancing image clarity is a secondary effect of using grids, as they improve contrast but are not primarily designed for clarity. Increasing patient exposure is contrary to the purpose of utilizing grids, which aim to improve image quality while minimizing the dose of radiation the patient receives. Improving color accuracy is not applicable in conventional radiography since it primarily deals with monochromatic X-rays. Thus, the main purpose of a grid is indeed to reduce scatter radiation, which leads to clearer and more diagnostic images.