Radiologic Technologist Practice Exam

In radiography, what effect does increasing milliamperage (mA) have on the image?

1. Decreases exposure time

2. Increases image contrast

3. Decreases image noise

4. All of the above

The correct answer is: Decreases image noise

Increasing milliamperage (mA) in radiography directly influences the quantity of x-ray photons produced during an exposure. This increase in photon production enhances the overall signal reaching the image receptor, which helps to improve the quality of the resulting image. By increasing the mA, there is a notable decrease in the exposure time needed to achieve the same image density. This reduction in exposure time is beneficial as it minimizes the potential for motion artifacts caused by patient movement during longer exposures. The heightened amount of photons also leads to a reduction in image noise, which is the random variation in image quality. By generating more x-rays, there is a greater likelihood that the image will maintain a stronger signal-to-noise ratio, meaning the essential details are clearer, enhancing image clarity. While it may be thought that increasing mA might also affect image contrast, this is not a direct consequence of mA changes alone; instead, image contrast is more closely related to factors such as beam quality (kilovoltage) and the inherent properties of the tissues being imaged. Thus, the most accurate choice in terms of the effects of increasing mA is that it decreases image noise, making the final answer related to this aspect most appropriate.