If the exposure factors for an x-ray of the lumbar spine are changed to 200 mA, 0.5 second, and 104 kV, what will be the main change observed?

When the exposure factors of an x-ray are adjusted to 200 mA, 0.5 seconds, and 104 kV, the primary change that occurs is in the scale of grays or contrast in the resulting image. The mA (milliamperage) affects the quantity of radiation produced, influencing receptor exposure, while kV (kilovoltage) impacts the quality or energy of the x-ray beam.

In this case, an increase in kV leads to higher energy photos that can penetrate denser tissues more effectively. This typically results in a broader range of grays in the final image, providing better differentiation between tissues with varying densities. A higher kV generally means a decrease in contrast because the x-ray beam is less absorbed by the body, leading to lighter images with a reduced scale of grays.

Receptor exposure is indeed affected by changes in both mA and exposure time (0.5 seconds); however, the contrast is predominantly impacted by the kV. Distortion is a function of positioning and focal spot sizes, which have not been altered in this scenario. Thus, the most significant alteration in this situation relates to the scale of grays or contrast, making it the correct choice.