Computed Tomography Scan

A Radiographer placing a Patient in the Gantry


This is an imaging method that makes use of X-rays to create cross-dimensional images of the body.

CT Scans include;

  • Chest CT Scan
  • Orbit CT Scan
  • Vertebra CT Scan
  • Abdominal and Pelvic CT Scan
  • Cranial/Head CT Scan

How is CT Scan Carried out?

The Patient is asked to lie on the Gantry Couch that slides into the gantry during scan.

Once the Patient is slide into the gantry, the X-ray beam rotates around them. Modern spiral scanners are consistent in performing this exam without stopping.

A computer is responsible for reconstruction of images collected from the Patient into slices, which can be stored and archived for diagnosis.

Patients before the scan are asked to keep still during the procedure as little movements could result in image blurring.

CT Scans run for few minutes and Patients are asked to leave the exam room and wait for results at the hospital reception.

How to prepare for a CT Scan?

CT exams vary as certain exams may require the use of a contrast agent. This contrast agent aid in better visualization of the body. And the Patient will be asked to maintain a dry fast for up to 6hrs before the exam.

Patients are required to consult their health provider on any reaction or allergy to contrast. Contrast used sometimes are Iodine.

Patient would be given a hospital gown, and is required to remove all jewelry.

The contrast may be given via an intravenous line (catheter), it may be drank by the Patient before the exam, which may taste chalky and is passed out of the body via stool.

On rare occasions, contrast are given as enema (through the rectum and into the GIT).

Patients on diabetes medications are required to consult their doctor if they are to carry out intravenous injection of contrast, as this contrast can worsen the health state of such Patient.

Need for CT Scan?

CT present with a detailed image for diagnosis of the body. It is vital in the;

Diagnose an infection

Study blood vessels

Guide a doctor to the right area during a biopsy

Identification masses and tumors.

Dangers of using CT?

Damage to kidney function from the contrast dye

Exposure to radiation

Allergic reaction to the contrast dye (mostly iodine). Antihistamins are prescribed by the doctor if the Patient must be given the contrast.

Dyes may cause anaphylaxis which may be life-threatening, thus Patient should make complaint if they find it difficult to breathe during the scan.

Patients are vulnerable to more radiation than regular x-rays. Multiple CT scans over time may raise the Patients risk for cancer. 

The Patient and the Radiographer should weigh the risks against the benefits of the CT scan. Although most recent CT machines have the ability to reduce the radiation dose.