Radiologic Technologist Practice Exam

Which exposure factor generally has the greatest effect on image density?

1. kilovoltage (kV)

2. milliamperage (mA)

3. exposure time

4. grid use

The correct answer is: kilovoltage (kV)

The factor that generally has the greatest effect on image density is kilovoltage (kV). Increasing the kV increases the energy of the x-ray beam, allowing for better penetration of the tissues being examined. This results in more x-rays reaching the image receptor, which in turn increases image density or darkness. A higher kV typically means that more photons are produced with greater penetrating power, which enhances the contrast and clarity of the image. This is particularly important for imaging denser structures, where a higher kV can help to achieve optimal exposure and enhance diagnostic quality. While milliamperage (mA) and exposure time also contribute to image density—mA controls the quantity of x-rays produced during a given exposure time—they do not have as significant an impact on the penetrating power of the x-rays as kV does. Therefore, when it comes to altering image density substantially, kV plays a more pivotal role. Grid use, on the other hand, primarily functions to reduce scatter radiation and improve contrast rather than directly affecting density.