IMRT (Intensity Modulated Radiotherapy) at Cancer Centre London

What is IMRT?

IMRT is the method of delivering high-precision radiotherapy using a computer-controlled linear accelerator. This allows our expert teams to deliver precise radiation doses to a malignant tumour or to specific areas within the tumour. This means that the tumour receives a very high dose and normal healthy cells nearby receive a much lower dose.

IMRT is the most widely used radiation therapy technique for prostate cancer in the UK and USA. Data from CT scans and MRIs are used to plan treatment delivery to the prostate.

IMRT (Intensity Modulated Radiotherapy) can also be used to treat bladder, oesophagus, pancreas and lung cases.

How does IMRT work?

The linear accelerator has a device called a multileaf collimator. The multileaf collimator is made up of thin leaves of lead which can move independently. They can form shapes that fit precisely around the treatment area. The lead leaves can move while the machine moves around the patient. This shapes the beam of radiation to the tumour as the machine rotates.

Each radiotherapy beam is divided into many small beamlets that can vary the intensity of radiation. This allows different doses of radiation to be given across the tumour.

Research has shown that IMRT also has the potential to reduce treatment toxicity, even when higher doses are delivered to the tissue being treated.

‘Forward planned’ IMRT can be used to treat breast patients. This ensures that a homogenous dose distribution is delivered throughout the entire treatment volume with heart and lung doses minimised.