The computed tomography or CT scan is referred to medical imaging procedure that uses x-rays and digital computer technology to create detailed 2D or 3D images of the body. CT scans are also known as computerized axial tomography. CT scan was developed independently by a British engineer named Sir Godfrey Hounsfield and Dr. Alan Cormack. It has become one of the main units for diagnosing medical diseases. For their work, they were jointly awarded the Nobel Prize in 1979.
CT scanners began to be installed first in 1974. CT scanners have rapidly improved patient comfort because a scan can be done quickly. Improvements have led it to higher-resolution images, which assist the doctor in making an easy diagnosis. Unlike other forms of medical imaging, the CT scan can make an image-slice of every type of body structure at once, such as bone, blood vessels, and soft tissue. The CT scanning equipment consists of a large supporting structure or gantry with a circular hole. Inside the gantry is a rotating ring that composed of the x-ray source and electronic x-ray detectors. An attached table holds the fully reclined person into the hole. Multiple x-ray images are taken in thin cross-sections along the person’s body. The detectors collect the x-ray projections from each cross-section and send them to a special computer that combines them into an image-slice.
When a CT scan is used
Some of the common uses of the CT scan are the following:
- Assessment of the structure and shape of an organ
- Diagnosis of disease, including cancer
- Diagnosis of trauma and injury
- Diagnosis of vascular diseases
- Aid to planning surgeries or radiotherapy
- Visual aid to radiotherapy administration or certain interventional procedures like biopsy or needle aspiration
- Measurement of bone strength
- Alternative to some exploratory or diagnostic surgery.
CT scan procedure
As a reference one may know, one may get the best CT scan center in Chennai, in India. Generally, the procedure involves:
A patient may be given a large drink to consume before the scan. This drink is an oral contrast agent which enhances the picture of the stomach, small intestines, and bowel. Sometimes, the contrast agent is administered as an enema. A patient may be asked to undress and wear a hospital gown. He must remove all metal objects including jewelry. Then he lies down on the scanner table. The radiographer may use straps and foam pillows to position the patient’s body and help keep him still. He may be given an intravenous injection of an iodinated contrast medium to help scan better images. This injection may cause a strange warm feeling that lasts for a few seconds, and a funny metallic taste in the mouth or the sensation that he has wet himself. Then the table slides into the circular hole in the machine.
Depending on the organ and particular condition being investigated, a number of projections may be taken as the table moves in and out of the circular hole. The gantry moves in a circle around the patient as it takes the x-ray images. Each turning of the gantry takes less than a second and there may be a number of revolutions or turning depending on the examination. The patient needs to lie very still. This is very important because movement will blur the images. He may be asked to hold his breath for a few seconds while the CT machine takes the images. The scanning equipment makes clicks and buzzes while taking the images and it is normal.
CT scan: Side Effects
CT scan is a very low-risk diagnosis process. The patient will be exposed to radiation when undergoing a CT scan, though, it is a safe level.
The biggest potential risk is with a contrast injection which is also called dye that is sometimes used in CT scanning. This contrast can help distinguish normal tissues from abnormal ones. It also helps to distinguish blood vessels from other structures like lymph nodes. Like any other medication, some people can have a serious allergic reaction to the contrast. The chance of a fatal reaction to the dye is about 1 in 100,000. Those who are at increased risk may require special pre-treatment and should have the test in a hospital setting. Anyone who has had a prior contrast reaction like a severe allergic reaction to other medications, or has asthma or emphysema, or has severe heart disease, those are at increased risk for a contrast reaction and referred to a hospital X-ray department for the exam. Besides an allergic reaction, the intravenous contrast can damage the kidneys, particularly if anybody already has marginal kidney disease. Usually, the patient is advised to drink plenty of fluids to help flush the contrast out of their system.
Any time an injection is done into a vein, there is a risk of the dye leaking outside of the vein under the skin. If a large amount of dye leaks under the skin, in some cases, this can cause the skin to break down.
After the CT scan
A patient may be asked to wait while the radiographer reviews the images. In some cases, more images need to be taken. Once the radiographer has enough good images, the patient can dress and leave. The medically qualified radiologist assesses the images. The results are usually sent to one’s referring doctor, so the patient will need to make a follow-up appointment. And one can get the best CT scan in Chennai in India. The CT scan is a non-invasive, painless and relatively safe diagnosis process that doesn’t require any recovery time. Be guided by one’s own doctor but, generally speaking, one can resume normal activities as soon as he leaves. There are no known long-term risks from having a CT scan. However, the procedure is thought to be increasing slightly a person’s chance of developing cancer. To keep this small risk in perspective, a typical CT scan will expose anyone to the same amount of radiation that he would receive from the general environment over about three years.