Introduction:
This is modified radiological technique discovered by Hounsfield & Ambrose. This technique is used to detect the abnormal structures and minor pathologies which could not be detected through other investigatory techniques, Computed tomography is a new method of forming images from X-rays. This is a multi directional scanning of the human body,By this multiple data is collected, calculated and finally images.
A computed tomography (CT or CAT) scan allows doctors to see inside your body. It uses a combination of X-rays and a computer to create pictures of your organs, bones, and other tissues. It shows more detail than a regular X-ray.
When the X-rays are subjected to body tissue, some X-rays are absorbed and remaining rays are taken by detectors as we see in simple X-rays but the difference here is, multi directional X-rays are taken in CT scan Equipment of computed tomography. The technique X-ray source & X-ray detector are placed on either side of the patient and also opposite to each other X ray source It is a thin source from which X-rays are ejected.When they pass thorugh the tissues of the body at a particular plane, some of these X-rays are absorbed by the tissues, and the remaining X-rays are received by the detector which is opposite side to the X-ray source The detector. This is placed opposite to the X-ray source to receive the unabsorbed X-rays at a particular plane. After a complete circular movement of the slice, the quantum of absorbed X-rays and reveiced X-rays are calculated.
How Do CT Scans Work?
They use a narrow X-ray beam that circles around one part of your body. This provides a series of images from many different angles. A computer uses this information to create a cross-sectional picture. Like one piece in a loaf of bread, this two-dimensional (2D) scan shows a “slice” of the inside of your body.
This process is repeated to produce a number of slices. The computer stacks these scans one on top of the other to create a detailed image of your organs, bones. For example, a surgeon may use this type of scan to look at all sides of a tumor to prepare for an operation.
•A computed tomography (CT or CAT) scan allows doctors to see inside your body. It uses a combination of X-rays and a computer to create pictures of your organs, bones, and other tissues. It shows more detail than a regular X-ray.
•You can get a this on any part of your body. The procedure doesn’t take very long, and it’s painless.
Advantages:
- CT scans can detect bone and joint problems, like tumors.
- If you have a condition like cancer, heart disorders or hepatocellular masses, CT scans can spot it or help doctors see any changes.
- They show internal injuries and bleeding, such as those caused by a car accident.
- They can help locate a tumor, excess fluid, or infection.
- Doctors use them to guide treatment plans and procedures, such as surgeries.
- Doctors can compare CT scans to find out if certain treatments are working. .
Disadvantages :
- cannot be used to assess individual renal function or degree of obstruction
- It is relatively expensive.
- It exposes the patient to a relatively high radiation dose (and thus should not be performed on pregnant women).
- Precise identification of small distal stones is occasionally difficult.
- Requires breath holding which some patients can not .
- CT scans of the brain can be affected by bone nearby.
- There is also a risk of childhood cancer and leukaemia in mothers who have imaging during pregnancy