CT Scan: Procedure, Uses & Risks

WHAT IS CT SCAN?

CT stands for Computed Tomography, earlier known as Computed axial tomography or CAT scan. This diagnostic medical imaging technique uses X-rays, which processes data to generate a three-dimensional image(3-D) of the internals of the body. The X-ray is taken from various angles of the body, the computer processing is then used for creating slices of bone, blood vessels, and other internal parts. This gives more detailed information than normal X-rays. CT scans are painless, accurate, and non-invasive techniques. Professional radiographers perform this type of scan.

HOW TO PERFORM CT SCAN?

CT Scanner

CT Scanners use a fixed motorized source of X-rays that rotates around the circular- opening of a tunnel-like structure known as a gantry. The gantry has a row of detectors that measures X-ray attenuation by various internal parts of the body. The patient has to lie down on the bed that slowly moves in the gantry. Each time the X-ray source completes the full revolution, the CT computer uses mathematical analysis for generating a 2-D image slice of the patient. Once a full slice is completed, the image gets stored and the motorized bed gradually moves forward into the gantry. 

Subsequently, with the help of a CT computer, the image slices is either displayed individually or stacked together to generate 3-D images of the internals of the patient.

There are few things to keep in mind while undergoing a CT scan. You should wear loose-fitting clothes, you may even need to wear a hospital gown during the procedure. Contrast material is used to get a clear view of internal images. In that case, you will be asked not to eat or drink for a few hours before undergoing a scan. Avoid wearing any metallic objects, like jewelry, hairpin, dentures as it may affect the CT scan images. However, CT scans can be used in patients with metallic implants or pacemakers where MRI is ill-advised. It is mandatory to lay still to avoid a generation of blurry pictures. If a child needs a CT scan, medical professionals might recommend sedatives to keep the child from moving. It is wise to inform your doctor of any medical condition beforehand, whether you have any recent illness and other medical history. 

USES OF CT SCAN:

CT scans were first developed in the 1970s, and since then it is proving to be of great use in imaging techniques. CT scans are minimally invasive and can be conducted quickly and has served a wide purpose- industrial use, geological use, cultural heritage use but the main use that we are going to discuss is in the field of medicine. We can diagnose diseases and evaluate the extent of injuries. Let’s discuss some of its uses:

Brain CT scan
  • Diagnosing infections, muscle and bone disorders, for instance, fractures and bone tumors.
  • Aids in studying the blood vessels and other internal structures of the body.
  • Brain CT scan provide information about brain structures and tissues. We can assess brain tumors, lesions, injuries, structural abnormality when other imaging technique fails to do so.
  • Diagnoses and assesses the various kinds of diseases and conditions like cancer, liver masses, lung nodules, and heart disease.
  • Evaluating the effectiveness of particular treatments, for instance, cancer treatments.
  • CT scans can detect and assess the extent of internal bleeding and internal injuries.
  • Provides exact location of the tumor and masses, as in case of cancer.
  • CT scans provide real-time imaging that can be useful in guiding procedures like needle biopsies, surgeries, radiation therapy, and needle aspirations of areas of the body like lungs, abdomen, pelvis, and bones.

ROLE OF CT SCANS IN THIS PANDEMIC:

We cannot deny the fact that the second wave of the COVID-19 pandemic had hit India badly. CT scans played a great role in this coronavirus outbreak. Though, CT scans are not advisable to people with mild symptoms. Chest CT scans can help in diagnosing COVID-19 in patients with high suspicion of infection. Experts from China agreed that CT scans play a vital role in the early diagnosis of COVID-19 and evaluation of the disease. Scientists from China revealed that Chest CT scans found 97% of coronavirus infections.

RISKS ASSOCIATED WITH CT SCANS:

Though CT scans have plenty advantages but it is associated with few side effects. AIIMS director Dr. Randeep Guleria said that 1 CT scan is equivalent to 300-400 chest X-rays that increase the risk of cancer in later life, especially among the youth. CT scans use ionizing rays in the form of X-rays. Research shows that radiation can cause mutation, damage DNA which can lead to cancer. Single use of CT scan involves lower risk but the effect of radiation adds up over a lifetime. The risk increases with every CT  scan you take. 

It is harmful for patients with chronic kidney disease or oral fluid volume.

Some patients might be allergic to contrast dye material. In rare cases, it can cause anaphylaxis, which is a life-threatening allergic reaction.

CT scan during pregnancy has never shown any risk to the unborn child. However, the baby might be at a very slight if a CT scan is being used for examining the abdomen or pelvic area. The radiologists adjust the CT scan technique to lower the radiation level exposed to the baby if you inform them about your pregnancy, beforehand.

Children, especially infants tend to have a much higher risk of developing cancer, leukemia, and brain tumors, as their brains are in the developing stage till the age of 5. They are more sensitive to activate radiation-induced carcinogens. 

Doctors consider CT scans relatively safe and non-invasive; though they involve exposure to radiation. More research in pediatric CT and normal CT scans can help in reducing the risk posed by it. As of now, we have to keep its benefits in mind, refer your physician and radiologist whether the risks of CT scan exceeds its diagnostic value.

REFERENCES:

  1. https://www.radiologyinfo.org/en/info/bodyct
  2. https://www.radiologyinfo.org/en/info/safety-ct-pregnancy
  3. https://www.healthline.com/health-news/children-frequent-ct-scans-of-children-raise-cancer-risk-061013

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