What is Radiation Therapy (Radiotherapy)?

Radiotherapy is the branch of medicine that deals with the treatment of tumours (malignant or benign) through Ionising radiations.

How does Radiotherapy Work?

Radiation Therapy, or radiotherapy, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation Therapy works by damaging the genetic material within cancer cells. Once this happens, the cancer cells are unable to grow and spread. When these damaged cancer cells die, the body naturally removes them. Normal cells are also affected by radiation, but they are able to repair themselves in a way that cancer cells cannot. The main aim of Radiotherapy is to give maximum dose to target volume or tumour and give minimum dose to surrounding normal tissues.

Three-dimensional Conformal Radiotherapy (3DCRT)

In 3DCRT radiation is delivered according to size and shape of tumour from appropriate angles, with an attempt to block the normal tissues.

Intensity Modulated Radiotherapy (IMRT)

IMRT is a new way of giving radiation therapy which uses software-based planning and delivery of tightly focused radiation beams to tumours. This reduces the radiation dose to surrounding healthy tissues and organs and thereby resulting side effects.

Image Guided Radiotherapy (IGRT)

IGRT is a step ahead of IMRT towards precision. A CT scan of the patient is taken in treatment position before delivering radiation using cone-beam CT scanner attached to the linear accelerator. This ensures that the radiation is being delivered to the intended region in millimetre accuracy.

Volumetric Modulated Arc Therapy (VMAT)

Limitations of fixed field IMRT has led to development of arc-based IMRT in which the machine moves around patient at the time of radiation delivery. VMAT is arc-based approach to deliver IMRT with the following merits:

• Stereotactic Radiosurgery & Radiotherapy (SRS / SRT)

  SRS/SRT are high precision techniques which use highly potent biological dose of radiation delivered using a 3D coordinate system for the exact localization of the tumours, thus ensuring millimetre accuracy.

• Stereotactic Body Radiotherapy (SBRT)

  SBRT is similar to the concept of SRS applied for tumours in the body even with respiratory and other movements. It may include 1 to 8 high-dose radiation sessions to ablate the tumours with motion management techniques. This was not achievable previously and has much better outcomes than fractionated radiation therapy and is useful even in resistant tumours.

Total Body Irradiation (TBI)

Total Body Irradiation is a technique where radiation is given to the whole body as a part of conditioning of Bone Marrow Transplant (BMT). Technically it's quite challenging to cover whole body uniformly and saving vital organs like lungs.

Clinical benefits of High Precision Radiotherapy:

• Better sparing of normal tissues
• Better tolerance to the treatment
• Better quality of life
• Dose escalation to tumour in some patients
• Improved chances of cure