Diabetes and PET-CT prep
What to Eat the Day Before — Your PET-CT if You Have Diabetes
The day before a PET-CT scan matters more for you than for someone without diabetes. If your blood sugar is too high when you arrive, the scan may not go ahead — after you have already fasted, travelled, and paid.
Medically reviewed by Dr. Bharati Devi Gorantla, Medical Oncologist, MBBS · MD · DM (Adyar, Chennai) · ECMO · MRCP SCE (UK) · Last reviewed September 2026
- The day before counts — A low-carb day before the scan helps bring your blood sugar into a range where the scan can proceed.
- Different from standard prep — People without diabetes only need to fast from the morning. You need to watch what you eat throughout the whole day before.
- Local foods can work — Many everyday Telugu foods — eggs, paneer, dal, leafy greens — fit the low-carb requirement.
- Medicines need a plan — When to take your diabetes medicines on the scan day must be confirmed with your treating team at booking, not guessed.
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The day before a PET-CT scan, eat low-carbohydrate meals only — protein, non-starchy vegetables, and plain dal are safe. Avoid rice, roti, fruit, and sweets completely. This is different from standard PET-CT prep, which requires only a morning fast. Your diabetes medicines need a specific timing plan confirmed with your treating team.
PET-CT at CION starts from Rs 10,499 — among the lowest published prices in Hyderabad, with no hidden charges. Indicative price, as of September 2026.
How is diabetic PET-CT prep different from the standard prep?
Standard PET-CT prep is a simple fast from the morning of the scan — nothing to eat or drink except water before your appointment. No special diet the day before is needed.
For you, the preparation starts the day before. The tracer used in a PET-CT scan behaves like glucose in the body. If your blood sugar is elevated when you arrive, the tracer distributes unevenly and the images become unreliable. If your reading is above the level needed for a clear scan, the appointment may need to be rescheduled.
Eating low-carbohydrate meals throughout the whole day before — not just at dinner — gives your blood sugar the best chance of being in an acceptable range by the time of your appointment.
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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Which common Telugu foods are safe the day before — and which are not?
| Food or drink | Standard prep patient | Diabetic prep — your approach |
|---|---|---|
| Rice (anna) in any form | Fine the day before | Avoid — significantly raises blood sugar |
| Roti and chapati | Fine the day before | Avoid — high-carb even in small amounts |
| Idli, dosa, upma | Fine the day before | Avoid — rice- and semolina-based |
| Fruit of any kind | Fine the day before | Avoid — high natural sugar content |
| Sweets, sugary drinks, packaged snacks | Fine the day before | Avoid — directly raises blood sugar |
| Eggs — boiled or scrambled | Fine the day before | Safe — low-carb, good protein |
| Paneer — plain or lightly cooked | Fine the day before | Safe — small portions are fine |
| Dal — toor or moong, plain | Fine the day before | Safe — a small portion at one meal |
| Chicken or fish — grilled, not fried | Fine the day before | Safe — good low-carb option |
| Plain curd — no sugar added | Fine the day before | Safe — check your usual tolerance |
| Leafy greens — palak, gongura, methi | Fine the day before | Safe — eat freely |
| Non-starchy vegetables — sorakaya, beerakaya, kakarakaya | Fine the day before | Safe — filling and low-carb |
| Plain water | Encouraged | Drink freely throughout the day |
What to do the day before your PET-CT scan
Confirm your medicine timing at booking
When you book your scan, ask the centre exactly when to take your diabetes medicines the day before and on the morning of the scan. Write it down. Do not follow your usual routine without checking — the fasting window may change the timing.
Eat a low-carb breakfast
Eggs, paneer, or plain dal with non-starchy vegetables are good choices. Skip idli, dosa, upma, fruit, and fruit juice — even if these are your usual morning meal.
Keep lunch low-carb
A small portion of dal and sabzi without potato or yam is fine. Do not eat rice or roti at lunch, even if it is your usual meal.
Eat a light, low-carb dinner early
Plain curd, a small portion of paneer sabzi, or a boiled egg with leafy greens works well. Avoid chapati, fruit, or sweets at dinner.
Drink plain water freely all day
Water is not restricted and is actively encouraged. Staying well-hydrated helps the scan proceed smoothly. Avoid tea or coffee with sugar or milk unless your team has specifically cleared it.
Stop eating at the time your team specifies
Your centre will give you a specific stop time based on your appointment. Take or skip your medicines at the time your team has confirmed — do not guess or follow your usual habit.
CION does PET-CT in Hyderabad from Rs 10,499 — among the lowest published prices in the city — including an oncologist-reviewed report and a free Rs 950 consultation. Indicative price, as of September 2026.
Explore 92 more Preparing For and Having Your Scan Safely topics
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- How to Prepare for a PET-CT Scan: The Complete Checklist
- Preparing a Very Elderly or Frail Person for a PET-CT
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- 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
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- Why Your Kidney Function Test Is Needed Before a PET-CT
Radiation Safety & After-Scan Precautions
- Are You Radioactive After a PET-CT Scan?
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- 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?
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- Is PET-CT Radiation Different From Radiotherapy?
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- PET-CT Radiation Compared With CT, X-Ray and Natural Background
- Radiation Safety at Home After Your Scan: A Family Checklist
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- Simple Steps to Clear the Tracer Faster
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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
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- Why You Have to Wait an Hour After the Injection
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- PET-CT With a Pacemaker, Stent or Metal Implant
- PET-CT for Claustrophobic Patients
- PET-CT for Patients Who Cannot Lie Flat
- PET-CT for Patients With Anxiety or Panic Disorder
- PET-CT for Patients With Dementia or Confusion
- PET-CT for Patients With Incontinence or a Catheter
- PET-CT for Patients With a Stoma
- PET-CT for Patients on Long-Term Steroids
- PET-CT for Very Elderly or Frail Patients
- PET-CT for Very Heavy Patients: Weight and Bore Limits
- PET-CT for Wheelchair and Bedbound Patients
- PET-CT in Pregnancy: Why It Is Avoided
- Sedation and Fasting for a Child's PET Scan
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Common questions
Frequently asked questions
Can I just eat normally the day before and fast from midnight?
No — for people with diabetes, the day before matters as much as the fast itself. The tracer used in the PET-CT behaves like glucose in your body. If your blood sugar is elevated when you arrive, the scan images are not reliable and the appointment may need to be rescheduled. A low-carb day before is the most effective thing you can do to prevent this from happening.
What if I accidentally eat rice or roti the day before?
Call the centre as soon as you realise. They will decide whether to proceed or reschedule based on your blood sugar reading on the morning of the scan. Do not cancel on your own without speaking to the team — the right call depends on how much you ate, when, and what your reading is. Calling early gives them the best chance of keeping your appointment.
When should I take my diabetes medicines the day before and on the scan day?
This must be confirmed with your treating doctor and with the imaging centre at the time of booking — it depends on which medicines you take and what time your scan is scheduled. Do not adjust, delay, or skip your medicines based on general advice from any source. Write down exactly what your team tells you and follow that plan.
Is tea or coffee safe the day before the scan?
Plain black tea or black coffee without sugar or milk is generally considered acceptable on the day before, but not during the fasting window on the morning of the scan. If you usually add milk or sugar, avoid tea and coffee altogether the day before, as both add carbohydrates that can raise your blood sugar. Check with your team if you are unsure — guidance may differ based on your medicines and appointment time.
What happens if my blood sugar is too high when I arrive?
The team will check your blood glucose with a fingertip test before the tracer is given. If the reading is above the level needed for a diagnostically reliable scan, the appointment will need to be rescheduled. This is not a formality — a scan done with high blood sugar can produce misleading images and lead to the wrong conclusions. Eating low-carb the day before is the most practical way to arrive in range.