Which change would require the creation of a new X-ray exposure chart?

The creation of a new X-ray exposure chart is necessary when there is a change in the X-ray machine. Various characteristics of an X-ray machine, such as its tube output, filtration, and collimation, directly influence the quality and intensity of the radiation produced. Each machine has its own unique operating parameters, meaning that an exposure chart is tailored specifically to that equipment.

When a new X-ray machine is introduced, the operational settings and performance may differ from the previous one, leading to variations in the required exposure time for specific film types or anatomical areas. Adjusting to a new machine entails recalibrating exposure settings to ensure optimal image quality and patient safety, hence necessitating the development of an entirely new exposure chart.

Other factors, like changing the type of film or adjusting exposure time, might require modifications to existing charts but do not require their complete reassessment. The radiation source is also generally tied to the specific machine, and while it can affect the exposure settings, its changes would be encompassed in the overall adjustment needed for the new machine. Therefore, a new X-ray exposure chart is fundamentally dictated by changes to the X-ray machine itself.