If an x-ray image lacks sufficient receptor exposure, an increase in _____ is required?

An increase in mAs, or milliampere-seconds, is required when an x-ray image lacks sufficient receptor exposure. The mAs controls the quantity of radiation produced; essentially, it determines how much x-ray energy is delivered to the patient and subsequently captured by the image receptor. When the receptor exposure is insufficient, increasing the mAs allows for more x-rays to reach the receptor, thus improving the image's brightness and overall visibility.

This is particularly important because proper receptor exposure is crucial for generating a diagnostic-quality image. The other factors listed do not directly address the issue of receptor exposure in the same way. While kV affects the energy and penetrating power of the x-rays, it does not necessarily increase the quantity; instead, it can enhance contrast, so changes might not directly improve receptor exposure. Similarly, increasing the grid ratio or SID (Source to Image Distance) can complicate exposure without necessarily rectifying the issue of low receptor exposure alone. Hence, adjusting mAs is the most effective approach in this scenario.