If a radiographer typically uses 80 kilovoltage peak (kVp) and 3 milliampere-seconds (mAs) on a portable chest exam, what new mAs is needed when using an 8:1 grid?

In radiography, the use of a grid helps reduce the amount of scatter radiation that reaches the image receptor, which improves image quality. However, the presence of a grid also requires an increase in the exposure factors to maintain adequate image density. The 8:1 grid mentioned in the question denotes a grid ratio that is very effective in removing scatter but also absorbs some of the primary radiation, necessitating an adjustment in the milliampere-seconds (mAs).

When switching from a non-grid to a grid technique, radiographers typically need to increase the mAs to compensate for the attenuation of the beam caused by the grid. A standard rule of thumb is to increase the mAs by 2 to 4 times when employing a grid, depending on its ratio and the specific imaging conditions.

Given that the original settings on the portable chest exam are 3 mAs without a grid, applying the appropriate increase for an 8:1 grid results in a calculated requirement of 12 mAs to achieve the same image density and quality. This calculation is essential to ensure that the radiograph produced is both diagnostic and of high quality, as inadequate exposure can lead to under-penetration and loss of detail in the images.

Thus, selecting 12