The Computed Tomography (CT scan) is a technique that produces 2D or 3D cross sectional images of objects, contrary to the flat imaged conventional X-ray technique. The word tomography gets its name from the Greek word “tomos” meaning, “slice” or section and “graphos” means drawing. CT Scanning is used in studying tumors, fractures, infections, organs and various anatomic structures with great accuracy and in diagnosing various disease conditions.
What is a CT scan?
The CT scan is also called as CAT scan (Computed Axial Tomography). In this technique, a number of X- ray images are combined using a computer to form cross-sectional images of organs and structures. If needed, 3D images can also be obtained.
The scanning machine takes X-ray images of different parts of the body in various angles. It will be presented as X-ray slices of the body, which are put together by the aid of a computer. Basically, the images appear as a cross-sectional view of the body parts, from the skin to the central parts of the body. If all these different views are put together, it produces a 3D image.
Description of the technique:
The patient is made to lie on a motorized table that passes through a circular opening of the CT imaging system. The CT imaging beam comprises of an x ray source that emits a fan shaped beam that irradiates a part of the body. In typical examinations, the X-ray tube takes 10 to 50 rotations, with the table moving in coordination to the tube, through the circular opening
Detectors are present on the exit side of the patient, which receives the X-ray irradiations coming out from the body, as sliced X-ray snapshots. These X-ray snap shots are sent to a computer, where it is organized into cross-sectional, 2D or 3D pictures. A contrast medium is injected into the patient to record the vascular structures with clarity.
Instructions to the patient:
Some exams may require a dye, called the contrast medium that is either injected intravenously or given to the patient to drink. If this is the case, the patient should not take anything by oral, 4 to 6 hours before the test.
The physician should be intimated before, of any medical history of diabetes or kidney disease or any allergic reactions to Iodine and the necessary precautions and medications should be taken.
The contrast medium can give a metallic taste, or a burning sensation, which is absolutely normal and will go as the contrast medium is flushed out.
Indications of using the CT scan:
CT Scanning has a varied number of uses, when it comes to diagnosis and treatment plan. Some of them are,
For traumatic injuries, such ads blood clot and fractures.
To identify, tumors and infections.
To study the structure of bones, as in the case of osteoporosis.
To study the various anatomic structures in the abdomen, and organs such as liver, gall bladder and kidney and so on.
To study the location of tumors to perform biopsies.
This procedure is minimally invasive, but has prevented the need for surgeries and other invasive methods for diagnosis of ailments. The latest CT scans available are faster and more accurate. This technical advancement is hence a boon to the medical field.