Before you start treatment
Baseline PET-CT Before Treatment — Why It Cannot Be Skipped
A baseline PET-CT is taken before treatment begins so that every scan that follows has a fixed starting point. Without it, measuring how well your treatment is working becomes much harder — and sometimes impossible to do formally.
Medically reviewed by Dr. C. Raghavendra Reddy, Medical Oncologist, MBBS (Gold Medal) · DNB · DM (Medical Oncology, Gold Medal) · Last reviewed September 2026
- A reference, not just a scan — Every scan during and after treatment is read against this one.
- Records the starting point precisely — Tumour location, size, and metabolic activity — measured before treatment changes anything.
- Without it, response is harder to assess — Your team cannot formally measure change if there is nothing to compare against.
- The cost is worth defending — Skipping the baseline can result in more follow-up scans to resolve what a baseline would have settled.
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A baseline PET-CT maps where disease is — and how active it is — before any treatment touches it. Every scan you have later is measured against this one. Without it, your oncologist has no fixed reference to judge whether treatment is working. Most treatment plans begin with one for exactly this reason.
At CION, a whole-body PET-CT starts from Rs 10,499 — among the lowest published prices in Hyderabad. Indicative price, as of September 2026.
Why does your team need a scan before treatment begins?
A PET-CT before treatment records the extent and metabolic activity of your disease before anything changes. It is the only way to establish a true starting point.
Every scan taken during or after treatment is read alongside this baseline. Without it, your oncologist cannot formally measure whether the disease has responded, stabilised, or grown — only observe what the scan shows now.
A finding that looks alarming mid-treatment — a lesion appearing larger, a new area of uptake — can only be correctly interpreted if there is a before-and-after comparison. Without a baseline, the same result can look like progression when it is actually expected, or reassuring when it is actually new.
What a baseline PET-CT gives your treating team
- Where in your body disease is metabolically active at the start of treatment
- How brightly each area shows on the scan — a measure of biological activity, not size alone
- Lymph node involvement and distant sites that may affect which regimen is chosen
- Areas that are suspicious but not yet confirmed, so later scans can track whether they change
- A measured, documented starting point that formal response criteria can be applied against
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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MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
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MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
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Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
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Dr. Vinay Mamidala
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Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
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What your team can tell — with a baseline versus without one
| With a baseline PET-CT | Without a baseline PET-CT | |
|---|---|---|
| Measuring tumour response | Compared against a precise documented starting point | Estimated from notes and other earlier imaging |
| Identifying a new lesion | Confirmed — not present on the baseline scan | Uncertain — may have been there at the start |
| Reading an unexpected finding | Checked against baseline size and activity | No reference — harder to say if it is new or pre-existing |
| Applying formal response criteria | RECIST or PERCIST criteria can be used (ASCO, ESMO) | Formal classification is not possible without a baseline |
| Deciding to continue or change treatment | Based on documented change from the baseline | Based on current scan appearance only |
Did you know?
Standard response assessment criteria endorsed by ASCO and ESMO — including RECIST and PERCIST — require a baseline scan to formally classify whether a tumour has responded, stabilised, or progressed.
Without one, two experienced oncologists looking at the same mid-treatment scan may reach different conclusions. The baseline is what makes the comparison objective.
Source: ASCO and ESMO clinical guidelines on tumour response assessment (RECIST 1.1, PERCIST)
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
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
Can we skip the baseline PET-CT to save money?
Skipping it is rarely the saving it appears to be. If your team cannot formally measure treatment response, follow-up scans become harder to interpret and may generate more uncertainty — and more imaging — rather than less. The baseline is what makes every later scan meaningful. If cost is a concern, ask your oncologist whether a baseline is required for your specific protocol and whether any alternative imaging would serve the same purpose.
What if treatment has already started — can we still do a baseline?
Once treatment begins, the scan is no longer a true baseline — any result it shows may already reflect treatment effect. If this is your situation, tell your oncologist now. They may still scan to establish the best available reference point, or work from imaging taken before treatment started. This is a clinical decision based on your specific circumstances, not something the imaging centre decides alone.
How close to starting treatment should the baseline scan happen?
General oncology protocols recommend the baseline be taken as close to treatment start as is practical, so it reflects the disease before any treatment has changed it. The specific timing depends on your regimen and your oncologist's instructions. Your treating team — not the imaging centre — decides the schedule. If you have been given a treatment start date, ask your oncologist when the scan needs to happen relative to that date.
Will I need many more PET-CT scans after this one?
How many scans follow the baseline depends on your cancer type, your treatment protocol, and how your team assesses response. Many protocols include a mid-treatment and an end-of-treatment scan at minimum. Some cancer types are monitored more closely; others less so. Your oncologist will tell you when the next scan is planned and what question it is meant to answer. The baseline is the first in a sequence, not a standalone test.
The baseline showed more areas than we expected. Does that mean it has spread?
A baseline PET-CT maps disease that was already present — it does not cause or worsen it. Finding more areas than expected is distressing, but it means the scan is doing its job: giving your team the full picture before treatment begins, so the plan can account for everything. It is also not the same as spread during treatment; this was the picture before anything started. Talk to your oncologist about what each finding means for your specific plan.
Why PET-CT and not a regular CT scan?
A standard CT shows the size and shape of a tumour. A PET-CT adds metabolic information: how actively the tumour is using glucose, which reflects how biologically active it is. For many cancers, this metabolic signal changes before the tumour visibly shrinks, making PET-CT a more sensitive tool for early response assessment. Whether PET-CT or CT is appropriate for your situation depends on your cancer type and stage — your oncologist specifies which is needed.