Which of the following three characteristics do all helical scans possess?

Helical scans, also known as spiral scans, are a key aspect of modern computed tomography (CT) imaging. The characteristics that define all helical scans include a continuously rotating x-ray tube, constant x-ray output, and uninterrupted table movement.

The continuously rotating x-ray tube is essential as it allows for a smooth and consistent acquisition of data while the patient moves through the scanner. This rotation enables the generation of high-quality images without gaps in the data, which is necessary for creating comprehensive cross-sectional images of the body.

Constant x-ray output ensures that the radiation dose remains consistent throughout the scan, contributing to image quality and patient safety. This uniformity allows for better density ratios in the resulting images, making them clearer and more diagnostically useful.

Uninterrupted table movement during the scanning process means that as the x-ray tube rotates, the patient table is constantly moving at a consistent speed. This combination of rotation and table movement is what creates the helical or spiral path that the x-ray beam follows, ultimately providing continuous data acquisition and allowing for rapid imaging compared to older techniques.

In summary, these three characteristics are fundamental to the operation and efficacy of helical scans, making option B the only correct choice among the options provided.