Computed Tomography (CT)

What is Computed Tomography?

Computed Tomography (CT) is an imaging technique that uses x-rays to acquire very fine slices of data through the body. This data is then used to construct images of the body part and specific structures under examination. CT scans are only performed through the area of interest not the entire body.

At Southern Radiology you will be scanned on what is known as a multi-slice CT scanner. Multi-slice CT equipment acquires data and produces images of extraordinarily fine detail. The level of detail obtained allows the body part being scanned to be imaged in multiple directions and views including 3D representations.

Preparation – What to do before a CT scan

The preparation required for a CT scan varies with the actual body part being scanned and the clinical symptoms your doctor is investigating.

At Southern Radiology our staff will advise you of any specific instructions when you make your appointment. Any preparation advice given is very important to follow. All instructions are aimed at ensuring you receive a safe and accurate examination. At the time of booking please advise our staff of any medical conditions that may contraindicate standard preparation instructions or even the test itself.

If you have been told you may need to have a contrast injection we advise you to fast (nothing to eat) for 2 hours prior to your appointment. If you take regular medication discuss this with our staff when making your appointment. You should continue to take your medication unless otherwise advised. If you are a diabetic please ensure booking staff are made aware of this when you are making your appointment as variations in preparation instructions or booking times may be required to accommodate your needs. If you are pregnant or breast feeding it is imperative to advise our staff or this at when booking your appointment.

For all examinations we ask that you bring with you any imaging you had done of the area under investigation. Also bring any imaging that may be relevant to your current examination.

At Southern Radiology we require a written referral or request from a doctor before undertaking any medical imaging examinations. Please ensure you bring your referral with you to your appointment. Bring your Medicare card to your appointment for billing purposes.

The procedure – What happens during your appointment and CT scan?

The exact procedure for any medical imaging examination depends on what is being imaged and why.

Although there will be slight variations in what you can expect when you attend your CT appointment, as a general guideline:

You will need to register with our secretarial staff upon arrival
You will be required to fill out some essential safety and medical history paperwork before we can commence your test
For pelvic and abdominal scans you may need to drink either water or what is known as oral contrast prior to your scan
You may require an intravenous contrast injection – if this is required one of our Radiographers or nurses will insert a vascular cannula in a vein in your arm prior to your scan ( link to contrast)
You may be asked to change into a gown
For the CT scan you will be asked to lie on a table which will move through what is known as the CT gantry. The CT gantry is a “donut” shaped unit that is open at both ends and is approximately 50 centimetres wide. The table you are lying on will be moved through the gantry when the scan data is being acquired. For some scans you may be asked to hold your breath during this time. With the multi slice technology used at Southern Radiology holding your breath, if needed, is only for a few seconds.  The whole scan itself will take a few minutes.
Your attending radiographer will explain and discuss all aspects of your scan with you prior to your examination.  Also your consent will be sought prior to commencing any part of the procedure
After the completion of your scan you may be asked to remain on site for at least 15 minutes if you have had intravenous contrast.
After your examination there are several options available to you regarding your films and result. Our staff will discuss the most convenient option with you.

Appointment length – How long can I expect to be at Southern Radiology?

Your appointment includes the time it takes to:

register your details
complete important safety and medical history paperwork
complete necessary preparation steps
complete the scan
collect your films
Scan times may only take minutes but in order to allow for pre-procedural steps as well as aftercare as a general rule we advise you to allow an hour for your appointment.

For examinations with additional preparation or aftercare our staff will advise you of any further time requirements.

Is it safe?

CT scanners use x-rays which are a form of ionising radiation. All radiation is cumulative and has associated risks that cannot be avoided. CT scans are only performed where it is deemed the benefit of the examination will outweigh any potential risks.

At Southern Radiology with the combination of modern CT technology, specialised radiographers and the use of dose minimising techniques you can be assured that radiation doses are kept to as low as reasonably possible.

Southern Radiology CT scanners are equipped with dose minimising software and are regularly serviced and calibrated by specialised engineers to ensure accuracy. Our CT radiographers are specialised in their field and tailor techniques to match your specific requirements. At all Southern Radiology practices specialised shields are placed over particularly sensitive organs when needed and scans are confined to the specific area of interest.

Should you require intravenous contrast there is a small risk of allergic reaction. The possibility of reaction is minimised through investigation of your medical history and existing conditions. All our staff are trained in observing even the most minor signs of an allergic reaction as well as corrective actions.  CT scans that require intravenous contrast are not performed without a medical doctor on site should any further assistance be required.


Southern Radiology is a leading diagnostic imaging provider who is committed to providing prompt and professional care to both patients and referrers. We are one of the largest medical imaging providers servicing the southern, inner western and eastern suburbs of Sydney and led by our specialist diagnostic imaging radiologists, Southern Radiology provides you comprehensive diagnostic support across all imaging modalities.

Our services include diagnostic radiology, interventional radiology, cardiac CT, magnetic resonance imaging, nuclear medicine and obstetric and gynaecological imaging. The Southern Radiology network consists of private community and hospital based practices, as well as two imaging research facilities.

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