Am I radioactive after a PET scan? Can I be near my family, hold my children, sleep next to my partner, drive home or go to work? How long it lasts, what precautions actually apply, and what you can stop worrying about.

In cervical cancer a PET CT is asked one question above all: are the para-aortic nodes involved? The answer decides how far the radiation field extends. Why MRI and PET are both needed, the bladder problem that can obscure the pelvis, why menstrual cycle timing matters, and the three-month interval after chemoradiotherapy.

Oesophageal cancer surgery is major surgery undertaken for cure — and a PET CT exists in this pathway largely to check it can achieve that. Why staging needs endoscopy, EUS, CT and PET together, the timing rule after chemoradiotherapy, why reflux and stents complicate interpretation, and how preparation is adapted when swallowing is already difficult.

Colorectal cancer spreads to the liver predictably — and unusually, those liver secondaries can sometimes be removed with curative intent. That fact drives when a PET CT is needed and when it is not. Rising CEA, assessment before liver surgery, why rectal staging is an MRI question, and why mucinous tumours behave differently.

Head and neck cancer is where PET most often answers a question nothing else can — finding an unknown primary, and assessing the neck after chemoradiotherapy so that surgery can sometimes be avoided. Why the interval after radiotherapy is critical, why dental work and talking during the uptake period matter here more than anywhere else.

Breast cancer is the common cancer where a PET CT is often not the right next scan. When it genuinely adds something, why routine PET staging is not recommended in early-stage disease, where it has real limitations including lobular carcinoma and sentinel nodes, and the vaccination and positioning points that matter here more than anywhere else.

What a PET CT adds in lung cancer — nodule characterisation, mediastinal nodal staging and distant spread. Why a bright node still needs sampling, why tuberculosis complicates interpretation in India, when lung cancer is not FDG-avid, why the brain needs a separate MRI, and what to tell the centre when you book.

PET CT is more central in lymphoma than in almost any other cancer. What the baseline, interim and end-of-treatment scans each decide, what your Deauville score actually means, why scan timing after chemotherapy and G-CSF matters, what can light up and not be lymphoma, and why surveillance scans are usually not recommended.

“Triple phase” describes the CT part of the scan, not the PET part — and once that is clear, everything else makes sense. What the three contrast phases are, why they matter most in the liver, why well-differentiated HCC may not show on FDG PET, the preparation contrast studies require, and what to ask before booking.

How to read a PET CT scan price list in Delhi — why the same scan appears at very different rates, the five things usually excluded from a headline figure, the four questions that test any discount offer, and a half-hour method for comparing three centres properly.