Image-Guided Radiation Therapy (IGRT)

What is image-guided radiation therapy (IGRT)?

Image-guided radiation therapy (IGRT) uses imaging technology such as X-rays to visualise the position of the tumour so that radiotherapy can be delivered accurately. Accuracy is important not only to treat the tumour, but also to avoid normal tissues.

Image guidance corrects for variations in the position of the patient or tumour, including motion of the tumour within the body. For example, prostate and cervical cancer positions may vary daily based on the state of bladder or rectal filling, while the position of lung and liver cancers change with breathing.

All tumour types can benefit from increased accuracy but image-guidance is especially important when tumours are close to vital organs.

A second advantage is that oncologists can track changes in tumour size or shape over the weeks of treatment. Thus, the radiation plan can be adapted to the new shape, size and position to reduce side effects and improve accuracy. This is called adaptive radiotherapy.

IGRT and other radiation therapy

IGRT is often used as an add-on to improve the positional accuracy of radiation therapy treatments, such as intensity-modulated radiation therapy (IMRT), 3D conformal radiation therapy or brachytherapy.

Why do you need IGRT?

IGRT is suitable for all types of cancer, especially those located near important organs and tissues.

IGRT is also useful for tumours that are likely to move during treatment or between treatments, such as lung tumours affected by breathing.

As IGRT is able to detect changes to your cancer before each therapy, your doctor can tailor your treatment plan accordingly. This can result in:

• Fewer side effects
• More accurate radiation delivery
• More effective treatment

What are the risks and complications of image-guided radiation therapy?

IGRT is used as an add-on to radiation therapy. As such, it poses no additional risk or complication beyond the underlying risks of radiation therapy itself.

In fact, IGRT lowers the risk of side effects and complications due to the increased positional accuracy.

What can you expect in image-guided radiation therapy?

You will be asked to keep still during the imaging and radiation processes.

Estimated duration

Image guidance adds about 5 minutes to each daily radiation therapy session for the scan to be done and the position adjusted.

During the procedure

You will be carefully positioned on the treatment table with devices to help you maintain the position.

Your radiation therapist will take an image of your tumour using an X-ray, CT scan or ultrasound scan. Your radiation therapist will review the images and adjust your position if necessary, before starting the radiation therapy.

During the radiation therapy session, you may see or hear equipment moving around you when it captures images. Depending on where radiation is delivered, you may need to hold your breath for intermittent periods.

Care and recovery after image-guided radiation therapy

You may have to go for regular follow-up appointments with your doctor to check on your recovery and look out for any side effects, which may occur well after the procedure.

Contact your doctor if notice any new symptoms so that they can help you manage them.