CAMRT Radiography Practice Exam

What does a densitometer measure in radiography?

1. Image resolution

2. Intensity of light transmission

3. Radiation exposure

4. Heart rate variability

The correct answer is: Intensity of light transmission

A densitometer is an instrument used in radiography to measure the intensity of light that is transmitted through a radiographic film or other imaging material. It quantifies how much light passes through the material relative to the amount of light that is incident on it. This measurement is crucial for assessing the film's optical density, which reflects the degree of darkening on the film when exposed to radiation. This function is essential in radiographic quality control because it helps radiographers ensure consistent image quality by evaluating the film's performance. By understanding the intensity of light transmitted, radiographers can make necessary adjustments to exposure settings, developing processes, and other factors that influence the final image. The other options are not relevant to the role of a densitometer. For instance, image resolution pertains to the clarity and detail of the radiographic image, which is influenced by factors like focal spot size and pixel dimensions, not by light transmission measurement via a densitometer. Radiation exposure relates to the amount of radiation that a subject receives but is typically measured using dosimeters or exposure meters, not a densitometer. Lastly, heart rate variability is entirely unrelated to radiography and pertains to the analysis of fluctuations in heart rate, making it irrelevant in this context.