Low-dose CT

What is Computed Tomography?

Computer Tomography is an imaging technique that uses advanced type of X-ray exam to create three-dimensional images of your body. The CT machine moves X-rays in a circular motion around the body region being investigated and acquires X-rays of very thin slices of your body. CT may be used to visualise internal organs, head, neck, spine and extremities.

At Harbour Radiology you will be scanned using low dose Siemens multi-slice CT scanner. Multi-slice CT equipment allows for greater clarity and detailed images.

The examination usually takes 10-25 minutes depending on the nature of the test being performed, in rare circumstances it may take longer.

Preparation – What to do before a CT scan

At Harbour Radiology, our staff will advise you of any specific preparations when you make your appointment. We aim at ensuring our patients receive a safe and accurate examination, and it is therefore imperative you adhere to the instructions as failure to do so may lead to delays or rescheduling of your appointment.

CT scans that do not require preparation include many bone scans such as the brain, temporal bone, facial bone, spine, knee, and wrist.

For some CT scans, the radiologist injects intravenous iodinated contrast medium or dye to highlight certain blood vessels and organs. In these circumstances, you will often be required to fast (nothing to eat) for 2 to 4 hours prior to your appointment. Drinking water is permitted to keep hydrated. You should continue to take your medication unless otherwise advised. If you are a diabetic or have other health problems preventing you from fasting please talk to your doctor and or our receptionists who will be able to guide you as changes in preparation instructions or booking ties may be required to accommodate your needs. If you are pregnant or breast feeding it is imperative to advise our staff when booking your appointment.

Contrast media is considered very safe but there are some precautions to be aware of with regards to patients with poor kidney function or diabetes. If you suffer from any of these conditions or have a known allergy to contrast media please contact Harbour Radiology on 02 9188 5280.

The Procedure

Upon your arrival to our practice, you will need to:

  • Register with our reception staff
  • Required to complete essential safety and medical history paperwork prior to commencing test

The general procedure involves being positioned onto the table for the scan. After you lay down on the scanner table, it will move to position the part of the your body to be investigated in the middle of the scanner. The CT machine is not a tunnel, so you will nut feel enclosed, however it is a bit noisy. The bed continues to move to complete each scan and you may be asked by our radiographers to hold your breath while this happens. It is important that you do not move during the scan as this impacts image quality

If an injection of contrast media is required, our radiographer will discuss this with you before the procedure, and will be asked to sign a consent form. To administer the contrast media a small needle is required to insert a plastic tube called a cannula into your arm or hand. During the injection you may experience warm sensation and notice a metallic taste in your mouth, which are normal reactions to the contrast agent and dissipate within a few minutes. Any adverse reaction to the contrast agent is very rare, and our team at Harbour Radiology are fully trained in the unlikely event of a reaction.

Once the scan has ended the images will be checked and your cannula removed. The results of your test will be reviewed by the Radiologist and conveyed to your doctor.

Post Scan

In the majority of cases patients can return to normal daily live activities following a CT scan. In small percentage of cases patients can be allergic to iodinated contrast media although our staff take all necessary precautions and are highly trained if an incident was to occur. If you experience any of the following symptoms post CT scan:

  • Vomiting/nausea
  • Itchiness
  • Rash/hives
  • Sneezing
  • Dizziness /headache
  • Change in blood pressure
  • Swelling of the mouth/ throat

You must tell our staff immediately or if you have left the premise you should return to Harbour Radiology or go to your nearest emergency department or Doctor (whichever is closest).

Is It Safe?

CT scanners use X-ray which are a form of ionising energy, however the chance for absorbed X-ray to induce cancer or mutation leading to a disease is thought to be very small for radiation doses of the magnitude associated with CT procedures. CT scans are only performed where the benefit of the examination with outweigh any potential risks.

At Harbour Radiology by using modern Siemens CT technology, and ensuring our radiographers are highly trained and the use of dose minimising procedures we will ensure that radiation doses are kept to as low as reasonably possible.

North Sydney