What assumption is made about the effectiveness of different x-ray exposure techniques?

The assumption that different x-ray exposure techniques must be adjusted based on patient size is crucial in ensuring optimal image quality and patient safety. This is because patient size can greatly influence the amount of radiation required to produce a clear image. Larger patients may require higher exposure settings to penetrate through additional tissue, while smaller patients may require less radiation to achieve the same level of detail. By tailoring the exposure settings to fit the patient's size, healthcare professionals can minimize radiation exposure while maintaining the necessary image quality for diagnosis.

In contrast, the assumptions made by the other choices do not hold. The claim that all techniques provide the same resolution overlooks the vast differences in equipment and settings that can affect image clarity. Furthermore, stating that exposure time is irrelevant to image quality disregards the fact that longer exposure can lead to better detail, but can also increase the risk of motion blur if a patient does not remain still. Lastly, the idea that techniques are universally the same across different imaging modalities fails to recognize the fact that various imaging techniques (like x-ray, CT, or MRI) operate under different principles and therefore have unique requirements for optimal image acquisition. All these factors highlight why considering patient size in the adjustment of x-ray exposure techniques is essential for effective imaging.