Radiologic Technologist Practice Exam

In a scenario using the air-gap technique, which factor remains constant while other parameters may change?

1. Sharpness

2. Receptor exposure

3. Contrast

4. Spatial resolution

The correct answer is: Contrast

The air-gap technique involves increasing the distance between the x-ray tube and the image receptor to reduce the amount of scatter radiation that reaches the receptor. This technique enhances image contrast by minimizing scatter, which can obscure fine details and lower the quality of the image. While using the air-gap technique, contrast remains relatively constant across various imaging scenarios, assuming that the same type of subject is being imaged and the technique is applied consistently. Factors such as receptor exposure and sharpness can vary depending on the adjustments made to the kVp, mAs, or the positioning of the patient and the equipment, which might be altered to achieve different imaging results. Similarly, spatial resolution can change based on the availability of different receptors or adjustments in film-screen combinations. Therefore, in the context of the air-gap technique, contrast is the factor that generally remains stable as it is primarily influenced by how much scatter is comparable in relation to the useful signal, rather than the specific parameters involved in the acquisition process.