Not Sure Which Scan You Need? See a GP First

If you already know exactly what you want scanned and why, book it. If you are not sure — which part, which scan, or whether a scan is the answer at all — a ten-minute conversation with a doctor will usually save you more than it costs. Booking the wrong region is an expensive way to learn nothing.

This is general information, not medical advice. If you have symptoms that worry you, speak to a GP or call 111.

What ten minutes with a GP actually adds

A scan answers a specific question about a specific area. Working out what the question is, and where to point the machine, is a clinical job, and it is mostly done by history and examination rather than imaging.

Pain does not always come from where you feel it. Shoulder pain can come from the neck. Buttock and leg pain can come from the lower back, or from the hip, and the scan for each is different. A GP examining you can narrow that down in a way a booking form cannot.

There is also a simpler saving. Blood tests sometimes answer the question faster and far more cheaply than imaging, and an examination occasionally settles it on the spot.

Sometimes the honest answer is no scan

This is the part imaging providers tend not to say. For several common problems, guidelines actively discourage routine imaging.

NICE guideline NG59, on low back pain and sciatica in over-16s, tells clinicians: "Do not routinely offer imaging in a non-specialist setting for people with low back pain with or without sciatica in the absence of red flags, or suspected serious underlying pathology following medical history and examination."

The reasoning is not cost. It is that most episodes settle, that the findings rarely change what is done next, and that scans of people without symptoms very often show wear-and-tear changes that look alarming written down and mean very little. A report describing disc degeneration and mild bulging can leave you more worried and no better treated.

That does not mean imaging is never right for back pain. It means a doctor should decide whether you are in the group it will help.

Choosing the scan, not just the body part

Even when imaging is the right idea, the choice of modality matters, and it is not obvious from outside.

Ultrasound is often the right first test for soft tissue lumps, tendons, the gallbladder, the thyroid, the testes and blood vessels. It uses no radiation, it is quick, and it was running from about £69 to £540 for one area in September 2026 — well below a single-region MRI at roughly £249 to £840 and up. Prices are ranges observed on providers' own websites and change.

MRI is the detail scan for joints, spine, brain and soft tissue. CT is faster, better for bone, lung and acute abdominal problems, and uses ionising radiation. Our side-by-side on MRI versus CT goes through where each one earns its keep.

MRI is also priced per region, so "my back" is not a single purchase. Cervical, thoracic and lumbar are three scans. Getting the region right is worth real money.

Some scans need a doctor by law

Under the Ionising Radiation (Medical Exposure) Regulations 2017, anything using ionising radiation has to be requested by a referrer, defined as "a registered health care professional who is entitled in accordance with the employer's procedures to refer individuals for exposure to a practitioner". A patient cannot be their own referrer.

In practice that means CT, X-ray, DEXA and mammography need a doctor or other registered professional to request them. MRI and ultrasound sit outside those regulations, which is why self-referral is normal for those two and not for the rest. We have set this out in more detail in our guide to getting a private MRI without a GP referral.

So if the scan you are leaning towards is a CT, the GP conversation is not optional anyway. You may as well have it first, when it can still change the plan.

How to get the appointment

Your NHS GP is the cheapest route and knows your history, which is genuinely valuable — a referral from someone who has your records is worth more than a form filled in by a stranger. If the wait for a routine appointment is long, ask the practice whether a telephone appointment is quicker.

Private GP appointments are widely available, often same day or next day, and a private GP can act as referrer for scans that need one. Some imaging centres also offer a GP consultation alongside the scan, priced around £40 to £50 in September 2026 when booked with the scan itself.

A short word of warning about that last option. A consultation booked with a scan is useful for going through the report afterwards. It is less useful as the thing that decides whether you need the scan, because by then you have already booked it.

What to take with you

• A written timeline: when it started, what it does, what makes it better or worse.
• Anything you have already tried, and whether it helped.
• Previous scans, operations or injuries in the same area, with rough dates.
• Your current medicines.
• Any implant or device card, if you have one.

Ten minutes disappears quickly. Notes are the difference between a vague conversation and a specific one.

Questions worth asking before you leave

Ask which scan the doctor would request and why that one. Ask what would change depending on the result — if the answer is "nothing, we would treat it the same either way", that is important information. Ask whether it is reasonable to wait and see, and for how long.

If you are going to pay privately, say so. It changes the practical advice: which centre, whether the report should come back to the practice, and whether they will act on a privately obtained result.

Symptoms that need a doctor today

Some things should not go through a booking form at all. Sudden severe headache unlike any you have had. Back pain with numbness around the groin, or loss of bladder or bowel control. A new breast lump. Coughing up blood. Chest pain. Sudden weakness, facial droop or difficulty speaking.

For any of those, call 111 or go to A&E now. A scan next Tuesday is the wrong answer to a problem that needs assessing today.

Frequently asked questions

Do I have to see a GP before a private scan? Not for MRI or ultrasound, which you can usually book yourself. You do need a registered healthcare professional to refer you for CT, X-ray, DEXA or mammography, because those use ionising radiation and IR(ME)R 2017 requires a referrer.

What will a GP actually change? Often the scan itself — the region, the modality, or whether imaging is the right test at all. An examination can also settle a question a scan cannot, and blood tests sometimes answer it faster and more cheaply than any image would.

Can I use a private GP instead of my own? Yes. Private GP appointments are widely available, usually same-day or next-day, and a private GP can act as referrer for scans that need one. Some imaging centres offer a GP consultation alongside the scan, priced around £40 to £50 in September 2026.

What if the GP says I don't need a scan? Take that seriously. Guidelines discourage imaging in several common situations because it rarely changes what happens next and often finds harmless things that cause worry. You can still choose to pay for a scan, but you will be doing it knowing the reasoning.

What should I bring to the appointment? A short written timeline of the symptoms, anything that makes them better or worse, previous scans or operations on the same area, your current medicines, and any implant or device cards. Ten minutes goes quickly, and notes stop you forgetting the useful details.

Once you know which scan you need, you can compare centres, prices and availability and book the right one rather than the nearest one.