Before your PET-CT
Can Diabetics Take Their Tablets — Before a PET Scan?
If you take tablets for diabetes, the answer is not simply yes or no. The instruction depends on which tablets you take — and if you do not confirm it at booking, you may arrive to find the scan cannot go ahead.
Medically reviewed by Dr. T. Raghavender Reddy, Medical Oncologist, MBBS · DM (Medical Oncology) · MD (Radiation Oncology) · Last reviewed September 2026
- Not one rule for all tablets — Different diabetes tablet classes carry different preparation instructions. What applies to one may not apply to another.
- Confirm at booking, not on the morning — The morning of the scan is too late to sort out your medication plan. Your instructions must be confirmed when the appointment is booked.
- High blood sugar can cancel the scan — If your blood sugar is too high when you arrive, the centre may need to reschedule. Good preparation prevents a wasted journey.
- Tell both your doctor and the centre — Your oncologist and the imaging centre each need to know you are diabetic. Neither can give you complete instructions without knowing your specific tablets.
17+
Cancer Specialists
on Panel
on Panel
96.9%
Breast Cancer
Survival Rate*
Survival Rate*
15,000+
Patients
Treated
Treated
4.8★
Google Rating
(800+ reviews)
(800+ reviews)
Many oral diabetes tablets need to be paused or taken at a different time on the day of a PET scan. The exact instruction depends on which tablets you take. Your treating oncologist and the imaging centre both need to confirm your specific plan when you book — not on the morning of the scan.
A whole-body PET-CT at CION costs from Rs 10,499 — among the lowest published prices in Hyderabad. Indicative price, as of September 2026.
Why does your blood sugar level affect PET scan results?
The tracer used in most PET-CT scans works like glucose. Your body handles it the same way it handles sugar — which means that if your blood sugar is already elevated, the tracer cannot concentrate accurately where it needs to.
Some diabetes tablets lower blood sugar in ways that also change how the tracer distributes through the body. This is why the preparation instruction is specific to your tablet class, not a single rule for all diabetic patients.
Centres check your blood sugar on arrival before the tracer is given. If it is above the level they consider safe for an accurate result, the scan will be rescheduled. Preparation prevents that.
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.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Interventional Radiologist
Dr. Mohammed Imran
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
You do not have to work this out alone
A 45-minute consultation with a specialist who treats this every week.
How do you prepare your diabetes tablets for a PET scan?
Tell your oncologist when the scan is referred
When your doctor refers you for a PET scan, tell them which diabetes tablets you take. They will advise whether any adjustments are needed and include the relevant information in the referral to the imaging centre.
Confirm the tablet plan at the time of booking
When the imaging centre contacts you to schedule the scan, tell them again that you are diabetic and list the tablets you take. They will give you specific instructions for the evening before and the morning of the scan. Write them down.
Read the fasting and tablet instructions together
You will be asked to fast before the scan. Your tablet instruction must be read alongside this, because taking a blood-sugar-lowering tablet while fasting can cause problems. Your confirmed plan will account for both.
Tell the team what you took on arrival
When you arrive for the scan, tell the radiographer exactly which tablets you took and at what time. Your blood sugar will then be checked. Only after that check is the tracer given.
Be prepared for a reschedule if your sugar is high
If your blood sugar is above the level needed for an accurate scan, the centre will reschedule rather than proceed. This protects the quality of your results. Rescheduling is not a failure of preparation — being scanned with inaccurate results is.
Did you know?
The tracer in a PET-CT scan and glucose compete for the same uptake sites in the body. When blood sugar is high, the tracer is diluted and distributes less predictably — which can make an active tumour appear less active than it is.
This is why a blood sugar check on arrival is not optional, and why centres reschedule rather than scan you when the level is not within the required range.
Source: EANM/SNMMI Guideline for 18F-FDG Use in Oncology
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 92 more Preparing For and Having Your Scan Safely topics
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
Contrast, Cannula & Procedure Safety
- Can You Have a PET-CT If You Are on Blood Thinners?
- Can You Have a PET-CT Through a Port or PICC Line?
- Contrast Allergy and PET-CT: What to Declare
- Contrast Reaction Symptoms: What to Watch For
- Contrast and Kidney Function: The Creatinine Rule
- Infection Risk and Hygiene at a Scan Centre
- Is Contrast Used in a PET-CT Scan?
- Metformin and Contrast: What Is the Rule?
- Side Effects of a PET-CT Scan
- The Cannula: Bruising, Pain and Difficult Veins
- Tracer Leakage at the Injection Site (Extravasation)
- What If You Feel Unwell During the Scan?
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
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
Special Populations
- Breastfeeding and PET-CT: How Long to Pause
- PET-CT Scans for Children: A Parent's Guide
- PET-CT With Kidney Disease or on Dialysis
- 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
Your next step
Talk to an oncologist about your scan
Your PET-CT report read by a senior oncologist, explained in plain language, with a free 45-minute consultation.
Common questions
Frequently asked questions
Do I stop my diabetes tablets the night before a PET scan?
Not automatically — it depends on which tablets you take. Some need to be paused the evening before; others only need to be delayed until after the scan; a few may be taken as normal. Your imaging centre will tell you the specific instruction for your tablets when you book. Do not follow general advice you have read online — the instruction differs by tablet class and the centre needs to confirm it for your situation.
Will I be turned away if my blood sugar is too high on the day?
Possibly. Blood sugar is checked on arrival before the tracer is given. If it is above the level the centre considers safe for an accurate result, the scan will likely be rescheduled. This means another fast, another journey, and a further wait for results. Getting your tablet instructions confirmed at booking, and following them carefully, is what prevents this.
I forgot to mention my diabetes tablets when I booked. What should I do?
Call the imaging centre as soon as possible — do not wait until the morning of the scan. They need enough notice to check your tablet against their preparation protocol and give you the right instruction. If you cannot reach the centre, contact your oncologist's office and ask them to liaise. Arriving on the day without having sorted this out means the centre may not be able to scan you.
Can I eat before a PET scan if I am diabetic?
The fasting instruction for diabetic patients is often modified compared to non-diabetic patients, to reduce the risk of low blood sugar. The exact eating and drinking instruction depends on your tablets and your usual control. Your imaging centre will confirm what applies to you when they book your appointment. Do not eat before the scan unless you have been explicitly told that it is safe for your specific situation.
My tablets are for type 2 diabetes — are the instructions different from insulin?
Yes, oral tablets and insulin carry different preparation instructions. But different categories of oral tablet also have different instructions from each other, so being on tablets does not mean one rule applies to you. Your imaging centre will know which category your tablet belongs to and will tell you exactly what to do. The instruction needs to come from them at booking, not from a general guide.