Scan Day: What Actually Happens
Is a PET-CT Scanner — Closed Like an MRI?
If the thought of lying inside a scanner is making you anxious, it helps to know what PET-CT actually looks like. It is not the narrow enclosed tube that many people picture. The ring is wide and open at both ends, and most people find it much easier than they expected.
Medically reviewed by Dr. T. Raghavender Reddy, Medical Oncologist, MBBS · DM (Medical Oncology) · MD (Radiation Oncology) · Last reviewed September 2026
- Open at both ends — Your head and feet are outside the ring for much of the scan. It is not a tunnel.
- Near-silent — Unlike an MRI, a PET-CT makes almost no noise. There is no loud banging or clicking.
- You can signal to stop — The technologist monitors you throughout. If you feel distressed, you can signal and the bed will stop.
- Sedation is available — If you have severe claustrophobia, mention it to your oncologist before the scan day. It can usually be arranged.
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A PET-CT scanner is much more open than an MRI. The detector ring is wide and open at both ends, so your head and feet are outside it for much of the scan. You lie still while the bed moves slowly through. Most people with mild claustrophobia manage it without sedation.
CION offers PET-CT in Hyderabad from Rs 10,499 — among the lowest published prices in the city, with no hidden charges. Indicative price, as of September 2026.
How enclosed is a PET-CT scanner compared to an MRI?
| Feature | PET-CT | MRI |
|---|---|---|
| Machine opening | Wide ring, open at both ends | Narrow tube, closed around the body |
| Head position | Often outside the ring during the scan | Inside the tube throughout |
| Noise | Near-silent | Very loud banging and clicking |
| Time fully enclosed | Minimal — bed passes through in short sections | Extended — body inside for most of the scan |
| Sedation commonly needed | Rarely | More often, for anxious patients |
What should you do if you feel panicky during the scan?
If you have ever felt panicky in a confined space, tell your oncology team before the scan day — not when you arrive at the imaging centre. Sedation needs to be planned in advance.
During the scan, you are never left unattended. The technologist monitors you from a room next door and can hear you at all times. Signal them and the bed will stop.
If your anxiety is severe enough that you do not think you can lie still, sedation is usually available if arranged ahead of time. Mention it at your next oncology appointment so it can be planned before the scan day.
PET-CT Partner Centres
PET-CT Scan Centres in Hyderabad
CION offers PET-CT scans through 4 trusted partner PET-CT centres across Hyderabad, so you can choose the one closest to you. Call 18002028726 and we’ll guide you to the earliest available appointment.
PET-CT Centre — Punjagutta
PET-CT Centre — Himayatnagar
PET-CT Centre — Narayanaguda
These are partner diagnostic centres within the CION network. Toll-free booking: 18002028726.
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What happens during a PET-CT scan?
Arrival and preparation
You check in at the imaging centre. Staff review your appointment notes and ask about recent food and drink. You may be asked to remove jewellery or metal objects.
Cannula placement
A nurse places a small cannula — a short, thin tube — in a vein, usually in your arm. This is the route for the radiotracer injection. It is similar to having a blood test.
Tracer injection and rest
The radiotracer is injected through the cannula. You then rest quietly, lying still and staying warm, while it travels to the right parts of your body. This rest period is the longest part of the appointment.
Moving to the scanner
You are taken to the scanning room and asked to lie on a narrow but padded bed. The technologist explains what will happen and answers any last questions before you start.
The scan
The bed moves slowly through the wide open ring. The scanner makes very little noise. You are asked to lie still and breathe normally. The team monitors you throughout. The imaging part of the appointment takes less time than the rest period.
After the scan
The cannula is removed. You can eat, drink and resume normal activities. The radiotracer clears from your body naturally over the rest of the day. Drinking plenty of water helps speed this up.
Did you know?
The injection given before most cancer PET-CT scans is a modified form of glucose, known as FDG. Cancer cells tend to absorb it more actively than the surrounding healthy tissue, which is what makes them visible on the scan.
This is why you are asked to fast before the appointment. Eating raises blood glucose, which competes with the tracer and makes the images harder for the radiologist to read.
Source: IAEA Human Health Series guidance on the use of FDG-PET in the management of cancer patients
PET-CT at CION starts from Rs 10,499 — among the lowest published prices in Hyderabad — across 4 partner centres in Banjara Hills, Punjagutta, Himayatnagar and Narayanaguda. Indicative price, as of September 2026.
Explore 64 more Preparing For and Having Your Scan Safely topics
Scan Day: What Actually Happens
- Can Someone Stay With Me During the Scan?
- Can You Drive Yourself Home After a PET-CT Scan?
- Can You Have Sedation for a PET-CT Scan?
- Can a PET-CT Scan Be Done on the Same Day as Other Tests?
- Contrast in a PET-CT Scan: When It Is Used and Why
- Eating and Drinking After Your PET-CT Scan
- How Long Does a PET-CT Scan Take?
- Is a PET-CT Scan Painful?
- Is a PET-CT Scanner Closed Like an MRI? Claustrophobia Explained
- The Tracer Injection: Does It Hurt?
- What Happens If the Scan Cannot Be Completed?
- What If You Cannot Lie Still or Have Tremors?
- What to Expect Immediately After the Scan
- Why Was My Scan Repeated or Extended on the Day?
- Why You Have to Wait an Hour After the Injection
- Your PET-CT Scan Day: What Happens, Step by Step
Diabetes & Blood Sugar for PET-CT
- A Diabetic Patient's PET-CT Day Plan
- Best Appointment Time for a Diabetic PET Scan
- Can Diabetics Take Their Tablets Before a PET Scan?
- Does Diabetes Change Your SUV Reading?
- Fasting Safely With Diabetes Before a Scan
- Insulin and PET-CT: Timing Rules
- Newly Diagnosed Diabetes Found Before a Scan
- PET-CT Scan With Diabetes: The Complete Preparation Guide
- PET-CT With Steroid-Induced High Sugars
- What Blood Sugar Level Is Needed for a PET-CT Scan?
- What Happens If Your Sugar Is High on the Day?
- What to Eat the Day Before if You Have Diabetes
Preparing for Your Scan
- A Printable PET-CT Preparation Card
- Can I Drink Water Before a PET-CT Scan?
- Can I Have a PET-CT Scan During My Period?
- Can I Take My Regular Medicines Before a PET-CT Scan?
- Can You Reschedule a PET-CT Scan?
- Cold Weather, Shivering and Brown Fat: Why You Are Asked to Stay Warm
- Fasting Before a PET-CT Scan: How Long and Why
- How to Prepare for a PET-CT Scan: The Complete Checklist
- Preparing a Very Elderly or Frail Person for a PET-CT
- Preparing a Wheelchair-Bound or Bedridden Patient
- Preparing for a PSMA, DOTATATE or FAPI PET-CT
- Should I Avoid Exercise Before a PET-CT Scan?
- Smoking, Alcohol and Caffeine Before a PET-CT Scan
- What Happens If You Break the Fast by Mistake?
- What to Carry to Your PET-CT Appointment
- What to Eat the Day Before a PET-CT Scan
- What to Wear to a PET-CT Scan
- Why Your Kidney Function Test Is Needed Before a PET-CT
Radiation Safety & After-Scan Precautions
- Are You Radioactive After a PET-CT Scan?
- Being Around Pregnant Women After a PET-CT Scan
- Can I Hold My Child or Grandchild After a PET-CT Scan?
- Can a PET-CT Scan Cause Cancer?
- Cumulative Radiation From Repeated Scans
- Do You Need Precautions After a PSMA or DOTATATE Scan?
- Do You Need Separate Utensils or a Separate Toilet After a PET-CT?
- How Long Does the Tracer Stay in Your Body?
- How Long Should You Avoid Close Contact After a PET-CT?
- How Many PET-CT Scans Are Safe in a Year?
- How Much Radiation Is in a PET-CT Scan?
- Is PET-CT Radiation Different From Radiotherapy?
- Is the Radiation From a PET-CT Scan Dangerous?
- PET-CT Radiation Compared With CT, X-Ray and Natural Background
- Radiation Safety at Home After Your Scan: A Family Checklist
- Radiation Safety for Staff and Attendants at the Centre
- Simple Steps to Clear the Tracer Faster
- Travelling Home After a PET-CT Scan: Public Transport and Airports
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Common questions
Frequently asked questions
How long will I actually be inside the scanner ring?
The imaging part — where the bed moves through the ring — is significantly shorter than the rest of the appointment. Most of the time is spent lying quietly after the injection while the tracer reaches the right parts of your body. If it is the scanner itself you are anxious about, it may help to know that the time inside the ring is brief. Ask the imaging centre staff when you book if you want a clearer sense of how the day is structured.
Can I have someone with me during the scan?
Usually not inside the scanning room itself, because the room contains low-level radiation from the tracer. A family member or carer can wait nearby and will be told where to go. If you are worried about being alone, mention it when you book — the imaging centre may have options, such as staff staying visible through a window, that can help.
Can I ask for a sedative before the scan?
Yes, and if you know from experience that enclosed spaces cause you significant anxiety, tell your oncologist before the scan day. Sedation needs to be planned in advance — your oncologist arranges it, and you will need someone to bring you to the appointment and take you home afterwards. Do not take a sedative prescribed for another purpose without telling your team first.
Is a PET-CT the same as a plain CT scan?
A PET-CT combines two scans in one machine. The CT part is the same rotating X-ray you may have had before — it shows the body's structure in detail. The PET part uses the radiotracer to show how active different areas are. Both are done on the same bed in the same session. The scanner looks like a CT ring rather than a long tube, which is why it feels much more open than an MRI.
What happens if I need to move during the scan?
Movement during the imaging part can blur the images, and that section may need to be repeated. The team will tell you when staying still matters most and guide you through any breathing instructions. If you feel uncomfortable or need to adjust, signal the technologist — it is better to pause briefly than to stay in distress. Repeating a section adds time to the appointment but does not affect your safety.