Spiral CT

Spiral CT is based on the technology called a slip ring.

It is a device that distributes the power supply between the patient table (or couch) and the gantry, which contains the spinning X-ray tube. The slip ring makes the simultaneous movement of the patient and X-ray tube rotation possible.

The process of CT imaging is faster, and the entire trunk can be taken in a single breath-hold. Thus, there is no respiratory misregistration. Also in spiral CT, 3D reconstruction can be done.

Spiral CT is the investigation of choice for renal stones. It is also used for staging of colon cancer and for visualization of pulmonary embolism.

Radiation exposure:

  • CT abdomen = 500 chest X-rays (highest)
  • CT head= 100 to 150 chest X-rays
  • Mammography = 20 to 25 chest X-rays.

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