Since its opening in 2019, ACOC Dubai is committed to delivering the most advanced care to its patients, especially in the radiation therapy department where the state-of-art linear accelerator Versa HD from ELEKTA was installed.

Dr Georges Farha

The aim was to give our patients access to the most advanced techniques enabling them to get the best oncologic outcome with the least possible toxicity.

Versa HD is a versatile machine capable of delivering the state-of-art technique developed so far, the intensity modulated radiotherapy (IMRT) with image guidance (IGRT).

What is IMRT?

IMRT is a specialized form of radiation therapy that allows radiation intensity to be changed (modulated) during treatment to precisely focus the radiation to cover just the tumor, thereby sparing normal surrounding tissue and organs at risk.

How it works

With IMRT, the radiation beam can be broken up into hundreds of “beamlets,” each of which can be adjusted to a different degree of intensity. In some cases, because of its extreme focus, IMRT can safely allow a higher dose of radiation to be delivered to a tumor to stop or slow its growth.

The linear accelerator has a device called a multileaf collimator (MLC), which is made up of thin leaves that move independently and form shapes that fit precisely around the treatment area. This means that the tumor receives a high dose and normal healthy cells nearby receive a much lower dose.

IMRT allows the dose to be shaped to the tumor by modulating (controlling) the intensity of the radiation beam. This allows different doses of radiation to be given across the tumour. It also avoids high radiation doses to structures that would otherwise be damaged by the radiotherapy and reduce the risk of long term side effects.

What’s IGRT?

In order to precisely focus the radiation to the tumor, we need to see what we treat. For this reason the Versa HD is equipped with one of the fastest Cone Bean CT (CBCT) scanner that ensure quick imaging of the treated area and precise focusing of the radiation to that area.

Volumetric Modulated Arc Therapy (VMAT)

VMAT is an advanced form of IMRT in which a single or multiple radiation beams sweep in arcs around the patient rather than remaining static. VMAT delivers a high-powered, targeted dose of radiation with minimal damage to surrounding tissue and critical anatomy, and because of its accuracy is often used for tumors that are adjacent to organs.

How it works

VMAT uses 3-D imaging to allow the radiation oncologist to verify the position of the tumor immediately prior to treatment, and to monitor the treatment in real-time to ensure the dose is delivered as prescribed.


Due to its high speed arc rotation, VMAT cuts treatment time significantly, which both lessens the amount of time patients must remain motionless and reduces the possibility that they will compromise the aim of the radiation by moving.

- The writer is Specialist, Radiation Oncology, ACOC