A procedure that uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body. The x-ray machine scans the body in a spiral path. This allows more images to be made in a shorter time than with older CT methods.
Axial non-volumetric scanning is how CT began where one (or just a few) slices are acquired during each gantry rotation. Traditional helical scanning (some call spiral) has the advantage of being faster than non volumetric axial scanning and also uses data continuously for improved motion robustness.
A spiral CT scan, also known as a helical computed tomography scan, is a non-invasive imaging procedure that uses an X-ray machine to create detailed cross-sectional images of the body:
n spiral CT, the patient is shifted continuously through the gantry while the x-ray tube and detector system rotate around the patient with data being acquired continu- ously. The patient travels at a speed of typically one slice thickness per 360” rotation; in practice this means values of l-20mm/s.
How it works: The patient lies on a table that passes through a donut-shaped scanner, while the X-ray tube rotates around the table. This creates a continuous spiral-shaped data set of images.
This allows more images to be made in a shorter time than with older CT methods. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly on the x-ray. Spiral CT scan also creates more detailed pictures and may be better at finding small abnormal areas inside the body.
Benefits: Spiral CT scans can:
Create more detailed images than older CT methods
Find small abnormal areas
Help diagnose disease
Plan treatment
Determine how well treatment is working
Radiation exposure: The amount of radiation absorbed during a spiral CT scan is similar to that absorbed during a mammogram.
Dye: A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly on the X-ray.
Cost: Spiral CT scans can be relatively expensive.
Identification of small stones: It can sometimes be difficult to precisely identify small distal stones.
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