What type of image artifact results from incompletely erasing a previous image?

Phantom or ghost images are artifacts that appear on an imaging technique when a previous image has not been completely erased before a new image is taken. This can occur in various imaging modalities, such as radiography or MRI, when residual data from an earlier scan persists, creating a misleading representation on the new image. These artifacts often resemble the original images, leading to confusion for the interpreting radiologist or technician, as they may be mistaken for current data.

In contrast, other options refer to different types of artifacts or issues. Moiré patterns occur when two grids or repetitive patterns interfere with each other, typically seen in digital imaging. Density artifacts relate to variations in image density that may be affected by exposure factors but are not specifically linked to the erasure of previous images. Caliper measurement is a specific measurement tool used for assessing distances or sizes in imaging but does not pertain to the issue of residual imaging data. Understanding the nature of these artifacts emphasizes the importance of proper image erasure protocols to ensure clarity and accuracy in radiographic interpretations.