Volumetric Modulated Arc Therapy (VMAT)

Volumetric modulated arc therapy [VMAT] builds further on intensity-modulated radiation therapy [IMRT] technology.

VMAT involves the use of external radiation therapy beams being directed in a series of arcs or angles by a rotating machine to allow for greater access to a cancerous tumour. The main advantages of this treatment are its precision and speed.

This therapy reduces the likelihood of impacting healthy surrounding tissues and allows more difficult tumours, such as ones wrapped around other important structures, to be targeted precisely.

VMAT technology allows different variables (e.g. gantry rotation speed, dose rate, MLC position) to be adjusted while the radiation beam is moving. With this, complex dose distributions can be achieved and treatment time is much shorter.

On average, each VMAT treatment is completed in less than two minutes, significantly shorter than conventional radiation treatments. Shorter treatment times improves the accuracy of radiation delivery while also improving the patient’s convenience and quality of life.

The VMAT technique is utilised in the head and neck cancers, prostate cancers, and lung cancer where radiation therapy needs to be delivered precisely to tumour while sparing surrounding healthy organs. This treatment is especially suitable for patients whose tumour is surrounded by normal tissues where treatment precision is most important. The added benefit is that VMAT is faster than IMRT and is especially suitable for patients who have difficulty remaining in the treatment position for prolonged periods of time.