Final answer:
Using an mAs value that is too high will result in a decrease in image contrast due to overexposure. This makes the radiograph appear denser and may obscure diagnostic details, possibly requiring a retake of the exam.
Step-by-step explanation:
If an MRT (Medical Radiologic Technologist) has selected an mAs (milliampere-second) value that is too high for the part being imaged it will result in an overexposed image. This overexposure will lead to a decrease in image contrast, as excess X-ray photons penetrate the subject matter and accordingly reduce the differentiation between various tissues. In diagnostic radiography the mAs controls the quantity of X-ray photons produced and thus the overall exposure. An excessively high mAs means more photons reach the image receptor resulting in increased densities on the finished radiograph.
The image on the radiograph will appear denser and darker than desired which may obscure important diagnostic details. In practice this can make it more challenging for clinicians and radiologists to interpret the image accurately and could necessitate a retake of the radiographic exam thus exposing the patient to additional radiation unnecessarily.