Computed Tomography Technologist Practice Exam

A change of less than 20% in milliampere-seconds (mAs) is generally considered to be the threshold for creating a visually noticeable difference in the image quality in radiology. This percentage is important for technologists to understand because it guides them in adjusting exposure factors while ensuring that image quality remains consistent and diagnostic.

When manipulating mAs, it's essential to balance the need for adequate image density with the risk of overexposing patients. Changes smaller than 20% typically fall within a range where the human eye cannot easily discern the difference in terms of brightness or contrast on the resulting images. This knowledge helps radiologic technologists make informed decisions about exposure settings, allowing them to fine-tune image quality without excessive adjustments that could compromise patient safety or diagnostic utility.

Understanding this threshold also assists in maintaining the ALARA principle (As Low As Reasonably Achievable) in radiological practices, as technologists aim to minimize radiation dose while still obtaining high-quality images.