Understanding why your doctor has referred you for a CT scan helps you feel informed and confident about your care. CT (Computed Tomography) provides fast, detailed images that help doctors diagnose, plan treatment, and monitor recovery.

What a CT scan shows

CT combines X-rays and computer processing to create clear cross sectional images of the body. It can reveal bones, soft tissue, organs, and blood vessels with high accuracy. This detail helps doctors identify internal problems that may not be visible with standard X-rays or ultrasound.

Common reasons for CT referral

• Head and brain: trauma, stroke, bleeding, tumours, or headaches.
• Chest: infections, lung nodules, blood clots, or cancer staging.
• Abdomen and pelvis: appendicitis, kidney stones, bowel or liver disease.
• Spine and bones: fractures, degenerative changes, or alignment issues.
• Vascular system: CT angiography to assess arteries, veins, and circulation.
• Cancer detection and follow up: monitoring treatment response and recurrence.

When CT is chosen over other scans

• When rapid results are required, such as after an accident or in emergencies.
• When more anatomical detail is needed than a standard X-ray can provide.
• When MRI is unsuitable due to implants, claustrophobia, or scan duration.
• When the focus is on bone, lung, or blood vessel imaging.

CT with contrast dye

In many referrals, contrast dye is used to highlight organs and vessels. This helps detect tumours, infections, and vascular disease with greater precision. The contrast injection is safe for most people and clears naturally through the kidneys.

Benefits of CT for your doctor

• Quick and widely available, most scans completed in under 20 minutes.
• Produces highly accurate 3D images for precise diagnosis.
• Guides surgeries, biopsies, and radiation therapy planning.
• Helps monitor progress and confirm that treatment is working.

Balancing accuracy and safety

Although CT uses radiation, doses are kept as low as reasonably achievable. The diagnostic information gained often far outweighs the small potential risk. Your doctor considers other options and refers you for CT only when it is the most appropriate test.

Questions to ask your doctor

• What is the CT scan looking for?
• Will it use contrast dye?
• Are there alternative tests for my condition?
• How will the results influence my treatment plan?

In summary

Doctors refer patients for CT scans when clear, fast, and detailed internal images are needed to guide diagnosis or treatment. The information from your scan helps ensure you receive the right care at the right time.

This guide outlines how to prepare for your CT scan, including what to wear, eating and drinking instructions, and information about contrast dye. Following these steps helps ensure accurate images and a smooth appointment.

Check your referral

Your referral form or booking confirmation will specify whether your scan requires contrast. Preparation can differ depending on the type of CT ordered by your doctor.

General preparation

• Bring your referral, Medicare card, and any previous imaging if available.
• Arrive 10–15 minutes before your appointment to complete forms.
• Wear loose, comfortable clothing without metal zips, belts, or buttons.
• Leave jewellery, watches, and piercings at home when possible.
• Continue taking your usual medications unless instructed otherwise.

Fasting and hydration

• If your scan uses contrast, avoid eating for 2–4 hours before your appointment.
• Drink water to stay hydrated; clear fluids are usually fine.
• If your scan does not use contrast, you can generally eat and drink normally.

Patients with diabetes or kidney conditions

• Tell us if you have diabetes or kidney problems. These conditions can affect how your body handles contrast dye.
• If you take metformin, you may need to pause it temporarily after your scan. We will give specific instructions.
• Bring a list of current medications with you.

Contrast injection preparation

• For contrast scans, a small IV cannula will be placed in your arm.
• Let staff know if you have had any reaction to iodine contrast before.
• Inform us of asthma, allergies, thyroid disease, or if you are pregnant or breastfeeding.

Pregnancy and children

• If you are or might be pregnant, inform us before your scan. We will assess whether CT is necessary or suggest an alternative such as ultrasound or MRI.
• For children, we tailor scanning protocols to keep radiation dose as low as possible.

On the day of your scan

1. Arrive a few minutes early to complete your questionnaire.
2. Remove metal items and change into a gown if required.
3. If contrast is used, you will have a brief consultation before the injection.
4. Relax and follow the radiographer’s instructions during the scan.

After your scan

• If you had contrast, drink extra water through the day to help flush it from your body.
• You can eat, drink, and resume normal activities immediately unless told otherwise.
• If you notice redness, swelling, or pain at the injection site, contact us or your GP.

Quick checklist

• Referral and Medicare card ready
• Loose, metal-free clothing
• Follow fasting instructions if contrast is used
• Drink water before and after
• Arrive early to allow time for paperwork

In summary

Most CT scans require little preparation. Following these simple steps helps ensure clear images and a safe, efficient experience. If you are unsure about fasting, medications, or contrast, contact our team before your appointment.

Some CT scans use an iodine based contrast dye to make internal organs and blood vessels show more clearly. This article explains how contrast works, when it is used, and what to expect during both types of scans.

What is contrast in CT?

Contrast is a clear liquid containing iodine. It is given through a small cannula in your arm or hand. The iodine temporarily circulates through your bloodstream, highlighting organs and vessels to help radiologists see structure and function in greater detail.

CT without contrast

• No injection is required.
• Shows bones, lungs, and some abdominal organs clearly.
• Commonly used for trauma, lung conditions, and bone injury.
• Shorter appointment and no aftercare needed.

CT with contrast

• Requires an IV cannula for the injection.
• Used to assess blood vessels, detect tumours, inflammation, or organ disease.
• Gives radiologists extra detail about how organs take up and release contrast.
• Takes a few minutes longer than a non-contrast scan.

What the injection feels like

During the injection you may feel warmth through the body or a metallic taste in your mouth. This is normal and passes quickly. You remain awake and can talk to the radiographer at any time.

Why contrast is important

• Improves visibility of blood vessels, kidneys, liver, and bowel.
• Helps detect subtle disease that may not appear on non-contrast images.
• Allows accurate diagnosis and treatment planning.

Safety and preparation

• Tell us if you have had a previous reaction to iodine contrast, kidney problems, or take metformin.
• We will review your medical history before proceeding.
• For most patients contrast is safe. Serious reactions are rare.
• After your scan, drink water through the day to help clear the contrast.

Common examples

• Brain CT without contrast: used for trauma or stroke.
• CT chest with contrast: used for clots, tumours, or infection.
• CT abdomen/pelvis with contrast: used for appendicitis, liver, or kidney disease.
• CT spine without contrast: used for fractures or bone injury.

After your scan

• If you had contrast, we remove the cannula and apply a small dressing.
• Drink water and continue normal activities.
• Seek care if you notice swelling, pain at the injection site, rash, or difficulty breathing.

In summary

CT with contrast gives more diagnostic information when soft tissue or vascular detail is important, while CT without contrast is sufficient for bones and lungs. Your doctor and radiologist decide which option provides the best balance of detail and safety for your condition.

This article explains CT scan safety, including radiation, contrast dye, and how we minimise risk.

CT safety at a glance

• CT uses X-rays, so it involves ionising radiation.
• Scans are performed only when medically justified.
• Dose is carefully controlled and kept as low as reasonably achievable.
• Most patients can resume normal activity immediately after the scan.

Radiation and risk

CT radiation can slightly increase lifetime cancer risk, but for an appropriate clinical question the diagnostic benefit outweighs this small risk. Your referrer and radiologist consider your symptoms, alternatives, and prior imaging before recommending CT.

When CT is recommended

• Urgent conditions where speed matters, such as trauma or suspected stroke.
• Problems best seen with CT, such as lungs, bowel, bones, and internal bleeding.
• Treatment planning and follow up when precise anatomical detail is needed.

Children and pregnancy

• Children: We adjust techniques for size and age and use CT only when it changes care. Ultrasound or MRI may be considered first.
• Pregnancy: Tell staff if you are or might be pregnant. We will discuss urgency, alternatives, and shielding or deferment where appropriate.

Contrast dye safety

Some CT scans use iodine-based contrast to highlight organs and vessels. Most people tolerate it well. A brief warm sensation or metallic taste can occur and passes quickly.

• Mild reactions can include nausea, itch, or hives.
• More significant reactions are uncommon. We are equipped to manage them.

Please tell us before your scan if you have

• Previous reaction to iodine contrast.
• Kidney disease or are on dialysis.
• Diabetes medicines containing metformin.
• Thyroid disease.
• Asthma or multiple severe allergies.
• Pregnancy or possible pregnancy.

How we minimise radiation

• We scan only the body area needed and avoid repeat phases unless essential.
• Automated exposure control tailors dose to your size.
• Low dose protocols and iterative reconstruction maintain image quality at lower dose.
• We check your prior imaging to avoid unnecessary duplication.

After your scan

• If you had contrast, drink water across the day.
• Minor bruising at the IV site can occur.
• Seek help if you develop worsening pain or swelling at the cannula site, hives, wheeze, or breathing difficulty.

FAQs

Is CT safe? CT is considered safe when medically justified and performed with dose optimisation.

Can I have CT while breastfeeding? Yes. If contrast is used, you can continue breastfeeding.

Will I feel anything? The scan is painless. Contrast may cause brief warmth or a metallic taste.

Are there alternatives? Depending on the question, ultrasound or MRI may be suitable. Your doctor and radiologist will advise.

Key point

For the right clinical question, CT provides fast, accurate answers with low, controlled risk. Talk to your doctor or our team if you have questions about safety in your situation.

CT stands for Computed Tomography. It uses a rotating X-ray source and computer processing to create detailed cross-sectional images of the body. Doctors refer patients for CT when fast, clear anatomical detail is needed to diagnose or plan treatment.

How a CT scan works

You lie on a narrow table that moves through a short, doughnut-shaped scanner. An X-ray tube rotates around you and captures many thin slices from different angles. A computer reconstructs these slices into clear images that show bones, organs, and blood vessels. The scan is painless and typically takes 5 to 15 minutes of imaging time.

Common reasons your doctor might request CT

• Head injuries, severe headache, or suspected stroke
• Chest symptoms including suspected clots, infection, or tumours
• Abdominal pain, kidney stones, appendicitis, or bowel issues
• Trauma assessment for internal injury or bleeding
• Bone and spine problems including fractures
• Treatment planning and follow-up

Safety and radiation

CT uses ionising radiation. The dose is kept as low as reasonably achievable while still producing diagnostic images. For most patients the benefit of accurate diagnosis outweighs the small risk from radiation. Tell the team if you are or might be pregnant so we can plan safely.

Contrast dye

Some CT scans use an iodine-based contrast dye to highlight blood vessels and organs. It may be given through a small cannula in your arm. You could feel a brief warm sensation or a metallic taste, which passes quickly.

Please tell us if you have:

• Previous reaction to iodine contrast
• Kidney problems or are on dialysis
• Diabetes medication containing metformin
• Thyroid conditions
• Asthma or multiple severe allergies

How to prepare

• Bring your referral and Medicare card
• Wear comfortable clothing without metal; you may be asked to change into a gown
• Avoid food for 2 to 4 hours before contrast studies unless advised otherwise
• Sip water to stay hydrated
• Arrive 10 to 15 minutes early to complete a safety questionnaire
• Continue regular medicines unless instructed otherwise

What to expect on the day

1. Check in and complete a brief form
2. For contrast scans a radiographer places a small IV cannula
3. You lie still on the table; the scanner makes quiet whirring noises
4. You may be asked to hold your breath for a few seconds during images
5. Most exams finish within 10 to 20 minutes; you can usually go home right after

After your scan

• Drink water across the day, especially if you had contrast
• You can resume normal activities unless told otherwise
• Minor bruising at the IV site can occur; seek care if you notice swelling, pain that worsens, hives, or breathing difficulty

Results

A specialist radiologist interprets your images and sends a report to your referrer, usually within one to two business days. For urgent cases we contact your doctor on the same day.

CT vs MRI at a glance

• CT: uses X-rays, very fast, best for bone, lungs, trauma, bleeding, involves radiation
• MRI: uses magnet and radio waves, takes longer, best for soft tissue, brain detail, joints, no radiation

Book a CT scan

Have your referral ready and contact our team to schedule your appointment. We will confirm any preparation steps specific to your scan.

This guide explains what will happen before, during, and after your CT scan so you can arrive prepared and know what to expect.

Before you arrive

• Bring your referral and Medicare card.
• Wear comfortable clothing without metal; remove jewellery where possible.
• If your booking involves contrast, avoid food for 2–4 hours unless told otherwise. Drink water.
• Continue regular medicines unless you received specific instructions.
• Tell us in advance if you are or might be pregnant, have kidney issues, take metformin, or had a prior contrast reaction.

When you check in

• Arrive 10–15 minutes early.
• Complete a safety questionnaire about allergies, implants, and medical history.
• A radiographer will confirm the scan region and preparation.

If your scan needs contrast

• A small IV cannula is placed in your arm or hand.
• During injection you may feel warmth, a metallic taste, or need to urinate; this passes quickly.
• We monitor you and communicate throughout.

Positioning and instructions

• You lie on a narrow table that moves through a short, open ring.
• Straps or cushions may be used to help keep still.
• You may be asked to hold your breath for a few seconds during images.

During the scan

• The scanner makes soft whirring sounds.
• Imaging itself is typically fast, often a few minutes.
• You can speak to the radiographer at any time via intercom.

How long it takes

• Total visit time is usually 15–30 minutes.
• Complex scans or contrast studies can take slightly longer due to setup.

After your scan

• If you had contrast, we remove the cannula and apply a small dressing.
• Drink water across the day to help clear the contrast.
• Resume normal activities unless given other advice.
• Minor bruising at the IV site can occur. Seek care if you notice increasing pain, swelling, hives, or breathing difficulty.

Safety

CT uses ionising radiation. We follow ALARA principles to keep dose as low as reasonably achievable while obtaining diagnostic images. The clinical benefit usually outweighs the small risk. Tell staff about pregnancy or possible pregnancy.

Results

A specialist radiologist interprets your images and sends a report to your referring doctor, usually within one to two business days. Urgent results are fast-tracked.

Frequently asked questions

Will it hurt? No. You need to lie still. Contrast can cause a brief warm sensation.

Will I feel claustrophobic? Unlikely. The CT scanner is a short, open ring, not a tunnel.

Can I drive afterwards? Yes, unless told otherwise.

Do I need to stop medications? Usually no. Follow any specific instructions you received.

Ready to book

Have your referral handy so we can confirm preparation and appointment times.