Preparing for your scan
How to Prepare for — Your PET-CT Scan
The preparation for a PET-CT scan is straightforward, but getting it wrong can mean the scan has to be rescheduled. This page takes you through each step — from the evening before to the moment you lie down in the scanner.
Medically reviewed by Dr. T. Raghavender Reddy, Medical Oncologist, MBBS · DM (Medical Oncology) · MD (Radiation Oncology) · Last reviewed September 2026
- Fasting is essential — Eating raises your blood sugar, which affects where the radiotracer goes and can obscure the areas your oncologist needs to see.
- Exercise the day before matters too — Strenuous activity draws glucose into muscles and can create bright areas on the scan that have nothing to do with your cancer.
- Most regular medications are fine — But you must confirm in advance — especially if you take medication for diabetes. Specific rules apply and they differ from the standard instructions.
- The appointment is longer than the scan — Allow a full morning or afternoon. Most of your time at the centre is spent resting quietly after the tracer is injected, while it is absorbed.
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To get accurate results from a PET-CT scan, you need to fast for several hours beforehand, avoid strenuous activity for 24 hours, and leave jewellery and metal items at home. Your imaging centre will confirm the exact instructions when you book. The steps below take you from the evening before to the moment you arrive.
CION does 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.
Why does preparation make such a difference to the results?
A PET-CT scan works by tracking a radiotracer — a small amount of mildly radioactive glucose — as it moves through your body. Cancer cells absorb more glucose than normal tissue, which is how they show up on the scan.
When you eat before the scan, your blood sugar rises and the tracer spreads across many cells rather than concentrating in the area your oncologist needs to see. The scan becomes harder to read, and in some cases has to be repeated.
Exercise has a similar effect. It directs glucose into working muscles, which can create bright areas on the scan unrelated to your cancer. Avoiding strenuous activity from the day before is as important as the fast itself.
What should I do, step by step, before my PET-CT?
24 hours before: stop strenuous activity
From the afternoon or evening before your scan, avoid vigorous exercise — gym sessions, running, long walks, or anything that leaves you breathless. Your centre will confirm the exact cutoff time when you book.
The evening before: eat the right meal
Eat a normal meal but avoid sweet foods, fruit, fruit juice, sweetened drinks, and high-carbohydrate dishes. A simple meal of rice or roti with protein is fine. Stop eating at the time your centre has told you.
Your fast begins: what is allowed
Once your fast starts, no food and no sweetened drinks. Plain water is encouraged — drink it freely. No tea, no coffee, no milk, no flavoured water, no fizzy drinks of any kind, including diet versions. Do not chew gum or use breath mints.
Morning of the scan: medication and diabetes
If you have diabetes or take medication for kidney disease, you should already have specific instructions from your treating team — do not follow the standard advice here. For all other medications, follow the plan you confirmed with your team in advance.
Arriving at the centre: what happens
Hand in your referral and previous scan reports at reception. You will have a brief health check, then the radiotracer is injected into a vein. After the injection, you rest quietly for a set period before the scan begins. Plan your day around being at the centre longer than you might expect.
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 do I need to bring to my PET-CT appointment?
- Your appointment letter and the referral from your oncologist or doctor
- A government-issued photo ID — Aadhaar card, passport, or driving licence
- Any previous scan reports, CDs, or films from earlier CT, MRI, or PET-CT scans
- A written list of all your current medications, including supplements and herbal medicines
- Loose, comfortable clothing — avoid metal zips, underwire, belt buckles, or heavy jewellery
- A small bottle of plain water for during your wait
- A companion if you feel anxious — the wait is long, and having someone with you is fine
Did you know?
The radiotracer used in a PET-CT scan is eliminated from your body within hours of the appointment.
Concerns about radiation are among the most common questions people ask before their first scan. The IAEA notes that the dose from a PET-CT is broadly comparable to that from natural background radiation over several months — a level considered acceptable given the diagnostic information the scan provides.
Source: International Atomic Energy Agency (IAEA) — Radiation Protection of Patients
A whole-body PET-CT at CION is Rs 10,499 — among the lowest published prices in Hyderabad — with a free Rs 950 oncologist consultation to talk through your report. Indicative price, as of September 2026.
Explore 64 more Preparing For and Having Your Scan Safely topics
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
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
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
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
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Common questions
Frequently asked questions
Can I drink water before a PET-CT scan?
Yes — plain water is not only allowed, it is encouraged. Staying well hydrated makes the injection easier and helps the tracer circulate correctly. What you cannot have is anything with sugar, flavouring, milk, or caffeine: no tea, no coffee, no fruit juice, no flavoured water, no fizzy drinks including diet versions. If you are unsure whether something counts as plain water, treat it as off-limits and ask the centre when you confirm your appointment.
What if I accidentally eat or drink something I should not have?
Tell the centre as soon as you can — before your appointment if possible, or when you arrive. Do not assume it will be fine and say nothing. Depending on what you consumed and how long before the scan, your team may decide to proceed or to reschedule. A rescheduled scan is frustrating, but it is better than a result that is difficult to interpret or needs to be repeated. Be honest about what happened — it helps your team make the right call.
I have diabetes. Do the same preparation rules apply to me?
No, and this is important. Preparation for a PET-CT when you have diabetes requires specific guidance from your treating team, because your blood sugar levels and your diabetes medication interact with how the radiotracer behaves. Do not follow generic preparation instructions. Contact your oncology team or the imaging centre several days before your scan so they can give you a plan that is safe for you. Do not leave this question for the morning of the scan.
Can I take my regular medicines on the morning of the scan?
Most medications can be taken as usual with a small amount of plain water, but there are exceptions — particularly for blood-sugar-lowering medications. The safest approach is to ask your treating team or imaging centre when you book, so you have a clear answer well before scan day. If you did not ask at booking, call the centre in the days beforehand. Do not wait until the morning itself, when you may not have time to adjust your plan.
How long will the whole PET-CT appointment take?
Longer than most people expect. The scan itself is relatively short, but you will spend a significant amount of time resting quietly after the tracer injection while it is absorbed. Plan for a full morning or afternoon. When the centre confirms your appointment, ask them for a specific time estimate so you can arrange transport and family commitments around it. The exact duration varies depending on which part of the body is being scanned and the protocol your oncologist has requested.