Final answer:
CT uniformity is tested using a uniform phantom where the Hounsfield Units (HU) should not vary by more than ±5 HU from baseline values. These tests are crucial for ensuring the diagnostic quality of CT images.
Step-by-step explanation:
CT uniformity is tested to ensure that computed tomography (CT) images display consistent values across the image field. This is crucial for accurate diagnosis and treatment planning. The test involves scanning a uniform phantom, which is an object of known uniform density. The images produced are then assessed for the uniformity of their Hounsfield Units (HU), which should not show significant fluctuation from the baseline values. The accepted standard is that the difference in numbers must not exceed ±5 HU from the baseline values. However, it’s necessary to consult the scanner’s manufacturer specifications for the exact tolerance, as requirements may vary.
Regular testing and quality control are essential to maintain the diagnostic quality of CT scans, and the uniformity test is just one of many quality assurance tests performed on these systems. Other tests include checks for spatial resolution, contrast resolution, noise, and artifact evaluation to ensure the system operates within acceptable parameters.