How is radiation dose measured during a CT exam?

During a CT exam, the measurement of radiation dose is primarily quantified using the computed tomography dose index (CTDI) and the dose-length product (DLP) metrics. The CTDI provides a measure of the absorbed radiation dose from a single slice of CT imaging, which represents the radiation received by the patient during a specific scan. It accounts for factors such as beam geometry and the amount of radiation used to acquire the image.

The DLP takes this a step further by combining the CTDI with the length of the scanned area, providing a comprehensive understanding of the total radiation dose for a given CT examination. This metric is particularly useful as it allows for comparisons across different CT protocols and types of scans, providing better insight into patient exposure to radiation.

The other options do not accurately reflect the methods used for measuring radiation dose during CT scans. Patient weight and height do not directly correlate with radiation dose. The percentage of image clarity is not a metric that measures radiation dose but rather reflects the quality of the images produced. Additionally, the total time of the examination is not a direct measure of radiation dose, as dose relates more to the exposure parameters like energy levels and scan length rather than duration.