Intensity Modulated Radiation Therapy (IMRT)

  • Reference Number: HEY-495/2016
  • Departments: Radiotherapy


This leaflet has been produced to give you information about the benefits of intensity modulated radiation therapy (IMRT). Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor, but may act as a starting point for discussion.   If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team caring for you.

What is intensity modulated radiation therapy (IMRT)?

MRT can create radiation beams of differing strengths; this is not possible with conventional radiotherapy. IMRT can also shape the radiotherapy beams more precisely. This means that different doses of radiotherapy can be given to different parts of the treatment area so the dose to nearby tissues is kept as low as possible.

There are different types of treatment. Your doctor will prescribe the most suitable type for you and explain the reason that radiotherapy has been recommended.

Why is IMRT beneficial to people?

The aim of radiotherapy is to keep the dose of radiation to the normal tissues as low as possible. With IMRT, lower doses of radiotherapy can be given to healthy tissue. This means that both short term and long term side-effects are reduced.

Are there any complications or risks?

Radiotherapy can cause a number of side effects however IMRT can reduce these risks.

Which side effects can be reduced by treating with IMRT?

IMRT is often used to treat tumours that are close to important organs or structures. For example, when IMRT is used to treat pelvic tumours it can reduce the risk of long term bowel problems such as:

  • Cramps or spasms in the bowel and/or feeling that you have not emptied your bowel completely (tenesmus).
  • Diarrhoea or severe constipation.
  • Needing to rush to open your bowels (urgency).
  • Passing a lot of wind.

IMRT can also be used to treat tumours in the head and neck region. The radiotherapy dose to important structures such as the salivary glands can be kept as low as possible. These structures are very sensitive to the effects of radiotherapy. IMRT can reduce the damage to them and reduce the risk of permanent mouth dryness (called xerostomia). IMRT may also allow higher doses of radiotherapy to be given to the tumour.

Should all radiotherapy patients have IMRT?

It is generally accepted that IMRT should be used in at least 1 in 3 people who are having radiotherapy which is aiming to cure their cancer. It may benefit many different people with different types of tumour although its main use is in the treatment of people with head and neck, prostate, bladder, lung and breast cancers.

How do patients find out if they should have IMRT?

When you are referred for radiotherapy your Clinical Oncologist (radiotherapy specialist) should advise if you are likely to benefit from having IMRT. The oncologist should then tell you if their centre can provide it. The Queen’s Centre for Oncology and Haematology, Castle Hill Hospital is one of these centres.

Is IMRT available to everybody that should receive it?

Many radiotherapy departments are currently able to provide IMRT for patients who require it. If your Clinical Oncologist agrees that you would benefit from IMRT, but they cannot provide it at their centre, then arrangements can be made to send you to another hospital where it can be provided. Your oncologist or another member of your healthcare team will be able to give you more information about how this will happen.

Why is IMRT not available at all radiotherapy centres in England?

IMRT can be delivered on all modern linear accelerators, commonly known as LINAC, which are electrical machines which produce the radiation beams. However, the processes required to design an IMRT treatment are far more complex than for standard radiotherapy. A small number of radiotherapy departments are still working towards being able to provide this service for all people that should receive it.

Hull University Teaching Hospitals NHS Trust (HEY)

At the Queen’s Centre for Oncology and Haematology, Castle Hill Hospital, the Hull University Teaching Hospitals NHS Trust has invested significantly in radiotherapy technology and currently has six treatment machines (called linear accelerators), four of which can deliver Volumetric Modulated Arc Therapy (VMAT) and IMRT. VMAT is a type of IMRT where the linear accelerator moves in a continuous circle around the patient. This means quicker treatment times and enables a reduction in the dose to the patient, therefore reducing the side-effects incurred.

These are complicated and involved processes. From your CT planning scan to start of treatment it can take up to three weeks. This is to accommodate the intricate planning involved and the quality assurance that the department undertakes to ensure you receive the best possible treatment.

The service is expanding the IMRT/VMAT delivery and now routinely plans and delivers these techniques for cancers of:

  • Head and neck
  • Urology
  • Gynaecology
  • Breast
  • Lung
  • Neurological patients when clinically appropriate
  • Oesophagus
  • Rectum

Not all patients will receive IMRT but your consultant will discuss the best treatment options available for you.

Radiotherapy department staff

Clinical Oncologist

This is your consultant who is an expert in radiotherapy, and will be managing your treatment. They will take the responsibility for deciding what dose and how many treatments will be best for you, and it is them who will oversee the planning of your treatment. You may see them or a member of their team at your initial planning appointment and you can see them during your treatment if you have any problems or queries.

Therapy Radiographers

Therapy Radiographers are specialist healthcare professionals that are trained to plan and deliver radiotherapy treatment and to use the specialist equipment. You will usually see the same team of radiographers and they will assist you with any questions or problems or refer you to a more appropriate person.

Specialist Nurses

You will probably see our Specialist Nurses at some point during your treatment. They are able to offer expert skin care advice for radiotherapy patients and are able to offer advice for many other radiotherapy related problems.

Physicists, Planning Technicians and Machine Technicians

Medical Physicists are specialist scientists who have a key role in the individual planning and quality assurance of your treatment along with the Planning Technicians. They may also have an input into the set up of your treatment. They work together with the Machine Technicians to ensure that the machines are reliable and working accurately.


At some point during your treatment you may meet student radiographers. Everything they do is fully supervised. If you would prefer our students not to be present during the planning and treatment please let a member of staff know when you attend for your initial planning appointment.

Other members of staff

During your treatment course you may meet our receptionists, dieticians, oncology health staff, patient services staff, clinical support workers, porters, volunteer workers and radiotherapy helpers. All are working together to provide you with a high quality of healthcare.

Useful contacts

Please note below the contact details of useful organisations that provide information about cancer including radiotherapy treatments:

Cancerbackup and Macmillan Cancer Support

This provides information from specialist nurses on all aspects of cancer and its treatment, and on the practical and emotional aspects of living with cancer.

Free phone help line: 0800 8001234 (Monday – Friday, 9am – 8pm).
Write to: 3 Bath Place, Rivington Street, London, EC2A 3JR.

PALS (Patient Advice and Liaison Service)

Provide confidential advice and support, helping you to sort out any concerns you may have about the care we provide, guiding you through the different services available from the NHS.

Telephone: (01482) 623065 (Monday – Friday, 9am – 4.30pm excluding Bank Holidays).

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Radiotherapy Information and Support Team on telephone number (01482) 461206Email:

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.