Intensity-modulated radiotherapy (IMRT) is a type of conformal radiotherapy, a technology that enables the radiation oncologist to precisely target the tissues with cancer cells. . In this type of radiation therapy for cancer, the radiation beams closely take up the shape of the area that is being targeted.

IMRT is delivered through the standard radiotherapy machine, which is also known as the linear accelerator (LINAC). This machine has a device called multileaf collimator, which possesses lead leaves that can move independently to form a shape that best fits the target area.

Because the radiation beams can take up the shape of the target area, high dosage of radiation can be delivered to kill the cancer cells while minimizing exposure to the non-cancerous cells and tissues. IMRT proves to be highly effective in the case of head and neck cancer among other types of cancer.IMRT for prostate cancer is now available across all major hospitals around the world.

The efficiency of IMRT has already been tested for multiple cancers, including breast cancer. Latest advancements improving the efficacy of radiotherapy, however, continue to take place in the field of healthcare. This radiation treatment for cancer is already being used as a standard treatment for some cancer types.

Stereotactic radiotherapy (SRT) is a type of technique used to precisely target radiation beams at the tumour. This is one of the latest innovations in the field of radiation therapy. Since this treatment requires special equipment, machine, and expertise, this treatment is not widely available across all cancer treatment hospitals.

SRT involves treatment of a tumour with the help of a special machine known as a linear accelerator (LINAC). This machine is used to deliver external radiation therapy in the case of normal radiation therapy and intensity-modulated radiation therapy (IMRT).

SRT treatment involves of small daily doses of radiation, which are also known as fractions. The patient may be advised to undergo anywhere between 3 to 30 fractions in a day, depending on the extent of cancer and the size of the area that is being targeted. SRT is mostly used for the treatment of smaller lesions and tumours and is less than 3 cms in size.

Stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) are types of SRT. SRS is also known as Gamma Knife surgery. It involves exposing the tumour to a very high dose of radiation in one to five fractions. Gamma Knife surgery is usually used for the treatment of a tumour in the central nervous system (CNS).

On the other hand, SBRT is a special procedure used for the treatment of tumours located outside the central nervous system. In this approach, radiation is delivered through different directions or positions of the body. It can be used for the treatment of small tumours in the lungs, pelvis, prostate, pancreas and other organs as well.

SRT is mostly used for the treatment of the following conditions:

• Secondary brain tumours
• Small lesion or brain tumour that has a well-defined edge
• Glioma that may have returned after months or years of treatment

Gamma Knife surgery is different from CyberKnife radiation. The latter is used for the treatment of cancerous and non-cancerous tumours as well as other medical conditions. CyberKnife treatment is actually a frameless robotic radiosurgery system that delivers a high dose of radiation to the targeted location.