What is Radiation Therapy (Radiotherapy)?

Radiotherapy is the branch of medicine that deals with the treatment of tumours (malignant or benign) through Ionicising 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. Main aim of Radiotherapy is to give maximum dose to target volume or tumour and give minimum dose to surrounding normal tissues.

Radiation therapy & Description

Features	Description
High-definition dynamic radiosurgery (HDRS)	Dynamic radiosurgery with software module to treat very small tumors without affecting normal organs
Stereotactic Radiosurgery (SRS)	Frameless non-invasive radiosurgery of head region capable of achieving high positional accuracy.
Stereotactic Body Radiation Therapy (SBRT)	High dose per sitting radiotherapy of body region capable of achieving high positional accuracy.
Volumetric Modulated Arc Therapy (VMAT)	Faster delivery of highly shaped beams without interrupting machine rotation
Image Guided Radiotherapy (IGRT)	Daily imaging during radiation therapy to improved accuracy & precision
Intensity Modulated Radiotherapy (IMRT)	Highly shaped beams to deliver radiation therapy with sparing of normal organs
Active Breathing Coordinator (ABC)	Breathing coordinator for chest & upper abdomen tumours to reduces dose to normal organs
Flattening Filter Free (FFF) beams	Delivers radiotherapy in 4-5 fold increase in dose rate, thereby reduces treatment time
Hexapod evo RT system	Robotic patient positioning platform providing six degrees of freedom and accuracy
4D CBCT& intrafraction imaging	Realtime imaging during the treatment delivery to detect tumour motion in lung & upper abdomen tumours.
Monte Carlo based algorithms & radiobiological based optimization (MONACO)	Specialized treatment planning software for achieving high dose calculation accuracy that uses biological cost functions.

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 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 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 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 its 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