Image-guided radiotherapy (IGRT)

The use of scans or X-rays taken at the radiotherapy machine, just before or during each session, to check your position and aim the radiation accurately.

✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review

In short

IGRT is imaging taken at the machine to check your position and aim the radiation accurately; it is not a separate treatment on its own.
It helps the planned dose hit the tumour and spares more healthy tissue, which can reduce some side effects.
The real benefits and risks for your cancer come from the radiotherapy it supports, which may be curative or palliative.
It adds a little extra imaging and time per session; it is a tool used where it helps, not something that makes radiotherapy a cure-all.

A plain-English summary. The detail — including risks and recovery — is below.

At a glance

TypeImaging used to guide radiotherapy accurately

AnaestheticNot needed (children sometimes need sedation or anaesthetic)

How long it takesAdds a few minutes to each radiotherapy session for imaging and adjustment

Hospital stayOutpatient

Time off workSame as the radiotherapy course it supports; fatigue is common

When you'll see resultsEffect comes from the radiotherapy itself, reviewed over weeks to months

On the NHS?Routinely used on the NHS as part of modern radiotherapy where appropriate

A general guide. Your specialist will give you advice for your situation.

Best fit

Checks and corrects your position at the machine, improving accuracy

Pause if

IGRT does not change whether radiotherapy is the right treatment; that decision is separate.

Main recovery point

Imaging and any position adjustment add a few minutes before the usually not painful treatment. You normally go home afterwards.

Good aftercare

Clear written advice on skin care and site-specific self-care.

Each session

Imaging and any position adjustment add a few minutes before the usually not painful treatment. You normally go...

During the course

Side effects from the radiotherapy (such as fatigue and skin reactions) build gradually. The team reviews and...

End of treatment to a few weeks after

Short-term radiotherapy effects often peak then settle, though fatigue can linger.

Months to years

Late effects from the radiotherapy can occasionally appear in the treated area. Follow-up checks response and any...

Medical line illustration of radiotherapy treatment for Image-guided radiotherapy (IGRT). — Illustration only - not a diagnosis, medical advice or a promise of result. Your anatomy and treatment plan may differ. Vuemedics does not publish before-and-after photos.

What is image-guided radiotherapy (IGRT)?

Image-guided radiotherapy (IGRT) is not a separate cancer treatment on its own. It is the use of imaging, such as a cone-beam CT scan or X-rays taken at the radiotherapy machine, just before or during each session to check that you are in exactly the right position and that the radiation will land where it should.

The body and tumours can shift slightly from day to day, for example with breathing, a full or empty bladder, or small changes in position. IGRT lets the radiographers see this and adjust before treating, so the planned dose goes to the tumour and less to nearby healthy tissue. It is often used together with techniques such as IMRT, and is part of how modern radiotherapy is delivered accurately.

Because IGRT is about accuracy rather than a different kind of treatment, the actual benefits and risks for your cancer come mostly from the radiotherapy it supports. The aim of that radiotherapy may be curative or to relieve symptoms.

IGRT adds a small amount of extra imaging dose and a few minutes to each session. The accuracy it gives is valuable in the right situations, but, like any technology, it is a tool to be used where it helps, not a feature that makes radiotherapy a cure-all.

Types, options & approaches

There may be different ways to do this. The right approach depends on the clinical question and your circumstances.

Cone-beam CT (CBCT)

A 3D scan taken on the treatment machine to check soft tissue and bony position before treatment, and adjust if needed.

Planar (2D) X-ray imaging

Quick X-ray images used to line up your position, sometimes against bony landmarks or markers.

Fiducial markers

Tiny markers placed in or near a tumour (for example in the prostate) that show up on imaging, helping the team line up accurately each time.

Motion management / 4D techniques

Methods to account for movement, such as breathing, so treatment is delivered when the tumour is in the right place.

Radiotherapy with vs without image guidance

Feature	What it means
Position checking	IGRT checks your position at the machine each session and adjusts
Margins	Better accuracy can allow smaller safety margins around the tumour
Healthy tissue	Less healthy tissue may be treated, potentially reducing some side effects
Extra imaging	IGRT adds a small extra imaging dose and a little time per session

IGRT improves accuracy; it does not change the underlying decision about whether radiotherapy is right for you.

Preparing for your treatment

Attend your planning (usually CT) appointment, where your position and treatment area are mapped.
If fiducial markers are needed (for example for prostate treatment), ask how and when these are placed.
Follow any site-specific preparation, such as bladder or bowel instructions, as this affects position accuracy.
Tell the team about all your medicines and other health conditions.
Tell them if you are, or might be, pregnant.
Plan for fatigue and for travel to daily sessions over the course.
Ask how IGRT will be used in your treatment and whether it adds much time per session.

What happens

Your radiotherapy is planned in the usual way, with a planning CT scan. IGRT then becomes part of each treatment session.

When you are positioned on the couch, the team takes imaging, such as a cone-beam CT or X-rays, on the machine. They compare this with your planning scan and make small adjustments to your position, or to the treatment, so the dose lands accurately. This adds a few minutes to each session.

The radiotherapy itself is then delivered as planned, and is usually not painful. You can normally go home afterwards. Over a course, this checking is repeated to keep treatment accurate as your body and the tumour shift slightly day to day.

Is this treatment right for me?

A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.

May not be suitable if…

IGRT does not change whether radiotherapy is the right treatment; that decision is separate.
Image guidance cannot rescue a plan for a cancer that is not suitable for radiotherapy.
Fiducial markers are not needed for every treatment and carry their own small procedure considerations.
Pregnancy remains a contraindication to the radiotherapy, regardless of image guidance.

Delay or rearrange if…

You are, or might be, pregnant, until this is resolved.
You have an active infection or are acutely unwell and need stabilising first.
Marker placement is needed but a bleeding or infection risk must be managed first.
Planning information is incomplete.

Alternatives to discuss

Radiotherapy with simpler position checks where high-precision guidance is not needed.
Different radiotherapy techniques (standard, IMRT or SABR) as clinically appropriate.
Surgery or drug treatments, alone or combined, depending on the cancer.
Active monitoring or supportive care where appropriate.

Before you decide

Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.

What matters most to me?

Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.

What are all my options?

Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.

What would make me pause?

Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.

What happens if I do nothing today?

For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.

Comfort, sedation or contrast choices

If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.

No anaesthetic (most adults)

Imaging and treatment are usually not painful; most adults need no anaesthetic and simply lie still.

Local anaesthetic for marker placement

Where fiducial markers are used, the small placement procedure may be done under local anaesthetic.

Sedation or general anaesthetic (some children)

Young children who cannot keep still may need sedation or a general anaesthetic for each session.

Benefits

Checks and corrects your position at the machine, improving accuracy
Helps the planned dose reach the tumour reliably
Can allow smaller safety margins, sparing more healthy tissue
May reduce some side effects by limiting dose to nearby structures
Helps account for day-to-day changes such as bladder filling or breathing
Supports more precise techniques such as IMRT and SABR

Risks & complications

More common

A few extra minutes on the treatment couch for imaging each session
A small additional imaging dose, which is minor compared with the treatment dose
All the usual side effects of the radiotherapy it supports (such as fatigue and a treated-area skin reaction)

Less common

Discomfort from longer time in the treatment position
A minor procedure to place fiducial markers, where these are used, with a small risk of bruising or infection
Occasional need to repeat imaging if the first images are unclear

Rare but serious

Marker placement complications (for example bleeding or infection), where markers are used
Serious risks that relate to the radiotherapy itself rather than the imaging, which the team should explain

IGRT itself is low-risk; it mainly adds a little time and a small imaging dose. The side effects that matter come from the radiotherapy it supports and depend on the treated area. If fiducial markers are used, ask about that small extra procedure. Ask your team how IGRT changes your treatment and whether it allows smaller margins.

Published figures to discuss

IGRT is an accuracy tool, so it does not have its own meaningful cure or complication rates. Its imaging dose is small relative to the treatment dose. The side effects and outcomes that matter come from the radiotherapy it supports, and those rates vary by cancer type, area, dose and fractionation. We have not stated percentages here; in general, fatigue and a treated-area skin reaction from the radiotherapy are common, while serious late effects are comparatively uncommon and site-dependent.

Figure	Reported range	How to interpret it	Source / confidence
Daily set-up shifts found by image guidance	Common	IGRT is used because anatomy and patient position move from day to day.	Guide sourcesClinical context
Imaging dose from repeated verification scans	Low compared with the treatment dose, but not zero	The benefit is more accurate treatment and potentially smaller margins.	Guide sourcesClinical context
Assuming IGRT removes all side effects	Common misconception	It improves targeting; normal tissues near the tumour may still receive dose.	Guide sourcesClinical context
Treatment delay if anatomy differs from the plan	Uncommon but useful safety stop	Bladder, bowel, weight change or tumour shrinkage can require adjustment before proceeding.	Guide sourcesClinical context

These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.

What happens afterwards

IGRT does not create its own recovery; it is part of how each radiotherapy session is delivered accurately. Recovery follows the radiotherapy course it supports, where fatigue and treated-area reactions often build during treatment and for a few weeks afterwards.

Each session

Imaging and any position adjustment add a few minutes before the usually not painful treatment. You normally go home afterwards.

During the course

Side effects from the radiotherapy (such as fatigue and skin reactions) build gradually. The team reviews and helps manage them.

End of treatment to a few weeks after

Short-term radiotherapy effects often peak then settle, though fatigue can linger.

Months to years

Late effects from the radiotherapy can occasionally appear in the treated area. Follow-up checks response and any late effects.

What's normal — and not a worry

A slightly longer time on the couch than radiotherapy without imaging
The usual building tiredness from the radiotherapy course
A treated-area skin reaction that improves over a few weeks
Site-specific effects depending on the area treated

Aftercare

Follow the radiotherapy team's skin-care and site-specific advice for the treated area.
Pace yourself and rest; light activity such as short walks can help fatigue.
If fiducial markers were placed, follow any advice on caring for the site.
Keep any site-specific routine (such as bladder filling) as instructed, as it helps accuracy.
Attend follow-up appointments so response and late effects are checked.
Know who to contact for advice and what counts as an emergency.

Before your treatment

Site-specific preparation (for example bladder/bowel) understood
Any fiducial marker procedure explained and scheduled
Skin-care products recommended by the team obtained
Support arranged for fatigue and transport for daily sessions
Contact number for the radiotherapy team saved
Follow-up appointments noted

⚠ Get urgent help if…

A high temperature, shivering or feeling very unwell, especially if you are also having chemotherapy, needs urgent contact with your team.
If fiducial markers were placed, signs of infection (increasing pain, redness, fever) at the site.
Skin in the treated area that breaks down, blisters or weeps and is not settling.
Severe or rapidly worsening pain.
Difficulty swallowing, breathing, or passing urine or stool, depending on the treated area.
Heavy or new bleeding.
Any symptom the team has specifically told you to report for your treatment area.

Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.

General guidance — it doesn't replace the specific advice your specialist gives you.

Results & realistic expectations

IGRT itself does not produce a result you can see; its value is in making the radiotherapy more accurate, so the planned dose reaches the tumour and less reaches healthy tissue. Any improvement in outcome or reduction in side effects comes through that accuracy.

The cancer's response comes from the radiotherapy, not the imaging, and is assessed over weeks to months. No radiotherapy guarantees a cure, and accuracy does not change the realistic aim, which your team will explain.

How long it lasts

Because IGRT is a way of delivering radiotherapy accurately, durability of the result depends on the cancer, the dose and any other treatments, not on the imaging itself. Late effects from the radiotherapy can appear months or years later, so follow-up continues after treatment.

Related tests, treatments or support

IGRT is routinely combined with techniques such as IMRT and SABR, and with motion-management methods for tumours that move with breathing. It supports, rather than replaces, the radiotherapy plan. The MDT and radiotherapy team decide how it is used for your treatment.

Follow-up & long-term care

Follow-up is the same as for the radiotherapy course IGRT supports: response is assessed over weeks to months, and you are watched for side effects including late effects. You should have a contact for questions and know what symptoms to report urgently.

Attend follow-up appointments, which may continue for years.
Continue any site-specific routine and skin care as advised.
Report new or persistent symptoms in or near the treated area.
Keep a record of the treatment area and dose for future clinicians.

Repeat, follow-on and what comes next

Imaging may be repeated within a session if the first images are unclear.
The plan may be adapted during a course if imaging shows anatomy has changed.
Further treatment may be needed if the cancer does not respond or recurs, as with any radiotherapy.
Markers, where used, usually stay in place permanently and are harmless.

Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.

What good aftercare looks like

Clear written advice on skin care and site-specific self-care.
A named contact and emergency instructions for side effects.
Care of any fiducial marker site where relevant.
Planned follow-up to assess response and watch for late effects.
Coordination with the wider cancer team and your GP.

What affects the cost

Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:

Whether image guidance is part of the radiotherapy package (it often is, as standard)
Any procedure to place fiducial markers
The radiotherapy technique it supports (for example IMRT or SABR) and number of sessions
Planning scans and the extra imaging at each session
Consultant oncologist fees and physics/radiography input
Follow-up appointments and management of side effects

Make sure your written quote includes

Whether image guidance is included as standard in the radiotherapy quote
Whether fiducial marker placement is needed and what it involves
The radiotherapy technique it supports and the number of sessions
What management of side effects and follow-up is included
How any combined treatments are costed and coordinated
What happens, and what it costs, if the plan changes or complications occur

On the NHS? Image guidance is routinely used on the NHS as part of modern radiotherapy where appropriate; private care may be used for speed or choice, but the imaging itself is a standard accuracy tool rather than a premium add-on that changes the decision to treat.

You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.

Choosing a specialist safely

Check the specialist is on the GMC Specialist Register for this area.
Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
You're entitled to your total cost in writing — including any follow-up — before you decide.

How Vuemedics verifies every consultant →

Questions to ask your medical professional

Take this to your consultation. A good specialist will welcome every one of these.

How will image guidance be used in my treatment, and does it add much time per session?
Will I need fiducial markers, and what does placing them involve?
Does IGRT let you use smaller margins and spare more healthy tissue in my case?
What is the aim of my radiotherapy: to cure or to control symptoms?
What side effects should I expect from the radiotherapy itself?
Who do I contact if I have side effects, and what counts as an emergency?
Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
Will you be the specialist who carries out my treatment, and who looks after me afterwards?
What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
What does a realistic result look like — and what can this treatment not achieve?
What are my options, including waiting, doing nothing for now, or choosing a different approach?
Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
What is the total cost in writing, including any follow-ups, and how much time do I have to decide?

Frequently asked questions

Is IGRT a different type of radiotherapy?

Not really. IGRT is imaging taken at the machine to check your position and aim the radiation accurately. It is used alongside radiotherapy techniques such as IMRT, not instead of them.

Does the extra imaging give me a lot more radiation?

The imaging dose from IGRT is small compared with the treatment dose. Teams keep it as low as reasonable while getting the accuracy they need.

Will IGRT mean fewer side effects?

By improving accuracy and sometimes allowing smaller margins, IGRT can reduce the dose to healthy tissue, which may lower some side effects. The main side effects still come from the radiotherapy and depend on the treated area.

Why do I need markers placed?

For some treatments, such as prostate radiotherapy, tiny fiducial markers help the team line up accurately each session. Placing them is a small extra procedure your team will explain.

Why does my bladder or bowel preparation matter?

A consistent bladder or bowel state keeps nearby organs in a predictable position, which helps IGRT keep treatment accurate and spares healthy tissue.

Does IGRT make radiotherapy more likely to cure my cancer?

IGRT improves accuracy rather than curing cancer by itself. Whether the aim is cure or symptom control depends on your cancer, and no radiotherapy can guarantee a cure.

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How we made this page

Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →

Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.

Sources & standards: Cancer Research UK — Image guided radiotherapy (IGRT) NHS — Radiotherapy NHS — Side effects of radiotherapy Macmillan Cancer Support — Radiotherapy side effects Royal College of Radiologists — Clinical oncology

Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.

Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.