IMRT (Intensity Modulated Radio Therapy) and IGRT Therapy for Prostate Cancer

Intensity Modulated and Image Guided Radio Therapy

Prostate cancer patients receive IMRT (Intensity Modulated RadioTherapy) radiation treatment to destroy cancer cells. Powerful x-ray beams are concentrated on cancerous prostate cells, as healthy organs and tissues are shielded from its effect. IMRT is a form of what’s known as conformal radiotherapy achieves high accuracy via IGRT (Image Guided RadioTherapy).

IMRT IGRT Image Guided Radiotherapy Prostate
Credit: Getty Images Ltd.


IMRT delivers radiation treatment to the whole of the prostate, often using a standard LINAC (Linear Accelerator) radiotherapy machine. Healthy tissues are protected by an incorporated multi-leaf collimator (eighty mini shields), that enables oncologists to dictate beam dosage and intensity with precision. Patients receive higher-dose radiation treatment, but with minimal side effects.


IGRT pre-scans recognise when the prostate has changed position within the body (typically due to tiny anatomical variations caused by the build-up of rectal gas or urine within the bladder). IGRT is vital in both achieving accuracy, and the protection of surrounding healthy tissues during treatment (accuracy and lower radiation levels reduce unnecessary damage).

What do IMRT and IGRT involve?

A computer can plan radiotherapy treatments using information gathered from initial CT MRI or PET scans of affected body parts; these scan images help consultants to carefully consider treatment options. When determining radiation dosage and treatment patterns, the shape and size of a patients tumour will also impact upon the computer’s final critical calculations.
When attaining accuracy; precision and overall best results for prostate cancer patients, radiotherapists often use other invaluable methods such as simple skin markers that provide defined reference points, or tailor-made radiotherapy moulds that minimise a patient’s movement throughout each treatment session.

The procedures

After radiotherapists have used IGRT to determine a patient’s correct body position (sometimes using markers and/or moulds), patients are required to lie still on a treatment table. The radiotherapist exits to an adjacent room to avoid radiation exposure (just as with standard x-rays), patients will be alone throughout the procedure; this should take no longer than half an hour.

Patient-doctor communication is typically using windows, intercoms and CCTV; this allows for specific directions or minor alterations (such as the regulation of a patients breathing) to be made throughout the procedure. IMRT is painless and patients won’t feel its impact during the treatment.

Side effects

Because side effects are only incurred when healthy tissues or organs are exposed to radiotherapy, they are automatically managed with procedural accuracy throughout these treatments. Although additional x-rays and scans marginally increase radiation exposure, side effects are minimal and most patient discomfort derives from their prolonged restriction of movement.

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