Preparing for Your Scan
What to Eat — the Day Before Your PET-CT Scan
Getting your diet wrong the day before a PET-CT can mean the scan has to be cancelled or repeated. The fix is simple: one day of high-protein, low-carbohydrate eating using food you can find in any Telugu household.
Medically reviewed by Dr. T. Raghavender Reddy, Medical Oncologist, MBBS · DM (Medical Oncology) · MD (Radiation Oncology) · Last reviewed September 2026
- No rice, no roti — These are the two most common day-before mistakes. Both raise blood sugar enough to affect the scan.
- Protein is your friend — Eggs, chicken, fish, paneer, and plain curd are all allowed and will not interfere with the tracer.
- Fruit is off the table — Natural fruit sugar has the same effect as sweets. Avoid all fruit and fruit juice the day before.
- Confirm your fast time — Your scan centre will tell you when to stop eating and drinking — confirm this at booking, not the night before.
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The day before a PET-CT scan, eat only low-carbohydrate food — protein and vegetables, no rice, no roti, no fruit, and no sweets. Carbohydrate raises your blood sugar and stops the scan tracer from distributing correctly, which can make the images unreadable. Confirm the exact timing of your fast when you book.
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.
Which foods are allowed the day before your scan?
| Food | Day before — allowed? | Why it matters |
|---|---|---|
| Eggs — boiled, scrambled, or plain omelette | Yes | Pure protein, no carbohydrate |
| Chicken or fish — plain boiled or grilled, no sauce | Yes | High protein, negligible carbohydrate |
| Paneer — plain, not fried or sweetened | Yes | Low carbohydrate, good protein |
| Plain curd — unsweetened, no sugar or fruit added | Yes | Low carbohydrate |
| Leafy vegetables — palak, methi, cucumber, tomato | Yes | Very low carbohydrate |
| Plain groundnuts — unsalted, small amount | Small amount only | Low carb, but eat sparingly |
| Tea or coffee — unsweetened, no jaggery | Small amount only | Sugar and excess milk raise blood glucose |
| Rice — white, brown, or any variety | No | High carbohydrate, raises blood sugar immediately |
| Roti, chapati, or parotta | No | Significant carbohydrate — same effect as rice |
| Idli, dosa, upma, or poha | No | Rice or semolina base — high carbohydrate |
| Fruit of any kind | No | Natural fruit sugar competes with the tracer |
| Fruit juice, sugary drinks, packaged drinks | No | Concentrated sugar |
| Sweets, halwa, mithai, or biscuits | No | Very high sugar |
Why does carbohydrate interfere with the scan?
The PET tracer is a glucose-based compound. When you eat carbohydrate, your blood sugar rises, and the tracer competes with that natural glucose for the same uptake pathways in your body.
If blood sugar is too high at the time of the scan, the tracer cannot reach the tissues your oncologist needs to see clearly. The images become unreliable, and in some cases the scan cannot be read at all.
One low-carbohydrate day prevents this. You do not need to fast the entire day before — you simply need to choose the right foods.
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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Day-before checklist
- Confirm your fast start time with the scan centre — they will tell you exactly when to stop eating and drinking
- Remove rice, roti, idli, dosa, and fruit from all meals today
- Plan each meal around eggs, chicken, fish, paneer, or plain curd
- Drink plain water freely throughout the day
- Skip strenuous exercise today — physical activity changes how the tracer is taken up by muscle
- Avoid all sugary drinks, including fresh juice and packaged drinks
- Do not start any new medicine without checking with your treating team first
What a low-carb day before your scan looks like
Breakfast
Two or three boiled or scrambled eggs with palak, cucumber, or tomato. Skip idli, dosa, bread, and upma entirely. Drink unsweetened plain tea or water.
Mid-morning
A small handful of plain, unsalted groundnuts, or a piece of plain paneer. Plain water or unsweetened black tea.
Lunch
Grilled or boiled chicken or fish with a large portion of sabzi — palak, lauki, or any non-starchy vegetable. No rice, no roti. If vegetarian: plain paneer or a small portion of dal with vegetables, no rice.
Afternoon
Plain unsweetened curd, a few groundnuts, or plain water. Avoid fruit and all fruit juice.
Last meal before your fast
Your scan centre will tell you when to stop eating. Have a protein meal — eggs, chicken, or paneer with vegetables — by that time. After your last meal, only plain water until your scan.
Did you know?
Elevated blood sugar at the time of a PET-CT is one of the most common reasons a scan has to be postponed or repeated.
It is also one of the most preventable — one careful day of eating is what keeps your appointment on track.
Source: Society of Nuclear Medicine and Molecular Imaging (SNMMI) patient preparation guidelines
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.
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Your next step
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Common questions
Frequently asked questions
Can I drink water during the fast on the morning of the scan?
Yes — plain water is encouraged right up until your scan. Staying hydrated helps the tracer move through your body and makes the intravenous line easier to place. What you cannot have during the fast is anything with sugar or calories: no juice, no milk, no sweetened tea, and no food of any kind. Your scan centre will confirm the exact window at booking.
I have diabetes. Is this diet safe for me?
Tell your treating oncologist and the scan centre before the day of your appointment. Diabetes changes how blood sugar behaves during a fast, and the team needs to plan your timing and monitoring accordingly. Do not adjust your diabetes medicines on your own. Your oncologist will give you specific instructions that fit your situation — the general guidance here may not apply to you as written.
Can I eat dal and sabzi, or is dal too high in carbohydrate?
Plain dal in a small portion is generally acceptable the day before, especially for vegetarians whose main protein is paneer or eggs. The foods to avoid are the high-carbohydrate staples — rice, roti, idli, dosa — not dal or leafy vegetables. If you are unsure about a specific dish, call your scan centre the day before and ask directly rather than guessing.
What if I accidentally ate something I should not have?
Call the scan centre as soon as you realise. Do not assume the scan will be cancelled, and do not assume it will still go ahead — the team will check your blood sugar when you arrive and decide then. Giving them advance notice lets them make a plan. Arriving without warning and being turned away is far more disruptive than a call the evening before.
Is plain tea or coffee allowed the day before the scan?
Unsweetened tea or coffee in small amounts is generally acceptable the day before — the carbohydrate impact is negligible without sugar or jaggery. Limit milk to a small quantity. On the morning of your scan, during the fast itself, check with your scan centre whether plain black tea or black coffee is permitted — centres differ on this point.