CT SCAN

Multi-slice low-dose Toshiba CTs are installed at all of our practice locations.

Computed tomography (CT, computed axial tomography or CAT) scanning is a diagnostic and interventional radiology technique that creates cross sectional images through any part of the body. CT images are created by passing low levels of X-ray radiation through the body. The radiation is produced by a shielded X-ray tube, mounted in a round gantry.

The patient lies on a table in an opening in the middle of the gantry. The X-ray tube moves within the gantry on a circular rail, travelling around the central hole and the patient on the table. A band of detectors in the shape of an arc is positioned opposite the X-ray tube. These detect changes in the density of parts of the body as X-rays pass though them, while the tube and detectors rotate around with the gantry.

During the CT scan, the technician can see and hear what is happening at all times. Occasionally, patients experience claustrophobia, but the CT scan times are very short.

Sometimes an intravenous injection of contrast material will be required during the examination, depending on the problem and the area being examined.

The final CT images are produced by a very powerful mapping computer that clearly shows many internal structures: soft tissues, bones, stones and parts of the body containing air, including the brain, neck, chest, abdomen, pelvis, arms, and legs.

Images can also be reconstructed to make 3D pictures of the body. This is routinely performed for the investigation of vascular anomalies, for example.

CT PREPARATION

Bring your request form, Medicare card and all old X-rays, scans, reports and films every time you visit us.

You are welcome to ask questions regarding your examination. A CT examination is typically 60 minutes but may be only 15-30 minutes. Let us know if you are on any medications for diabetes – this may alter the protocol for your scan.

Preparation varies depending on the type of examination. You may be asked to fast prior to your examination. Some examinations don’t require any preparation. You will be told what to do at the time of making your appointment.

Fasting requirements

  • CT scan of the head, neck, chest: Nothing to eat for 2 hours before the examination. A small amount of water may be taken. Continue all normal medications. An injection of X-ray contrast material may be required.
  • CT angiogram (additional instructions): No coffee, tea or chocolate for 8 hours before the scan. An injection of X-ray contrast material will be required.
  • CT scan of the abdomen and pelvis: Nothing to eat or drink for 4 hours before the appointment. You may need to drink an oral contrast given to you at the practice, up to 1 hour before the scan. An injection of X-ray contrast material is usually required.
  • CT scan of the abdomen (with colon views): Nothing to eat or drink for 4 hours before appointment. Please contact our practice to collect a kit 2 days prior and follow the dietary instructions. An injection of X-ray contrast material is usually required.
  • CT guided injections, and most other CT scan examinations, do not require any preparation. An injection of anaesthetic, X-ray contrast material and/or selected medications may be required.

WHAT HAPPENS DURING THE CT SCAN?

For the scanning procedure, you will be asked to lie on the scanner table. The part of your body to be examined will be positioned in the scanner by the technician (radiographer). You will hear a whirring or humming noise when the scanner’sX-ray tube and gantry rotate around you. No moving parts will touch you and there will be no discernible discomfort from the radiation.

Most CT scans take 15-60 minutes overall, which includes preparation, patient information confirmation, positioning and planning. The actual scan time for each acquisition is typically less than 10 seconds. During the scan, the technician can see and hear you at all times, as there is a camera and 2-way microphone built into the scanner. You can call for assistance at any time during the scan. Some patients experience slight claustrophobia, but the CT room layout and décor has been planned to minimise this.

Sometimes an intravenous injection of contrast material (“dye”) will be required, depending on the area being examined. The contrast can provide valuable information by improving visualisation of certain organs and blood vessels on the CT images. During the injection, you may notice a brief sensation of warmth and/or a metallic taste. These subside rapidly. Let the technician know if you have a history of any allergies.

CT SCAN SAFETY

If you are pregnant you must let our staff know before the examination.

At AdelaideMRI we have installed Toshiba CT scanners to provide our patients with the highest quality imaging. All of our Toshiba CT scanners use raw data acquisition with a slice thickness of only 0.5 mm. This means tiny structures inside the body, such as small blood vessels, or the bones of the ear, can be accurately imaged. This level of spatial resolution is the thinnest available slice thickness amongst all the scanners sold for medical imaging in Australia.

  • 0.5 mm detector elements are the thinnest available in any commercial scanner.
  • The industry-best low contrast resolution creates consistent soft tissue imaging at the lowest achievable dose.
  • Best possible image quality of small objects is achieved by isotropic resolution.
  • Reconstruction algorithms improve image quality, including special software to optimally image metallic reconstructions.

The result is the best achievable imaging coupled with the lowest achievable X-ray exposure.

The Toshiba 3-D Quantum de-noising system (patent-pending) enables us to reduce patient doses by up to 40%. Quantum de-noising gives us the choice of reducing dose without loss of image quality or improving image quality at our usual low dose settings. Importantly, the lowest suitable radiation dose is always used, including for paediatric imaging. If you are on medications for diabetes, you may be asked to withhold your medications for up to 48 hours after the CT study, or be re-booked for part of the study on another day. If you are not sure if this applies to you, please ask us before the examination.

CT SCAN RADIATION RISK

The intensity of X-rays used by a CT scanner is more than is used for a traditional X-ray examination. The amount of radiation used, however, is too small to accurately measure if there is any increase in the risk to the patient of cancer or other radiation-related injury. The amount of radiation used is kept as low as technically achievable. This is known as the ALARA (as low as reasonably achievable) standard that applies to all medical imaging.

Your doctor has decided that the medical benefit to you is greater than any risk of harm that might be posed by exposure to diagnostic X-rays in the CT scanner.

If you are pregnant you must let our staff know before the examination.
If you would like to know more about the risks and benefits of CT scanning, please ask the technician or speak to the radiologist when you attend for your examination.

CT COSTS

Imaging excellence and affordability are the cornerstones of our business. To meet this commitment, we BULK BILL all Medicare eligible CT Scans. Bulk billing means no gap payment and no large, unexpected out of pocket expense. Please check if your scan is eligible when booking. Medicare guidelines are very specific about which examinations are covered under the Medicare schedule.

It’s your choice where you have your Scan or X-ray. Call us with any practice’s Imaging request form for an appointment. . If your doctor has requested an X-ray or scan, you can use our request form at any radiology practice.

Sometimes your doctor may require traditional large-format plastic images. If this is the case, let us know and we will print plastic images for you – a surcharge applies for these copies.

CT RESULTS

The radiologist or technician will talk to you before, during and after the examination. The radiologist will interpret and report on the CT images. Often a second radiologist will also review your scan images and the final report will be issued the following day. The results will be sent to your referring doctor. As the images are digital they will be kept on our computer system for future reference. You should always discuss the results with your doctor.

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