The use of high-energy ionizing radiation to destroy cancer cells is known as Radiation Oncology. This type of treatment involves the use of high-energy X-Ray or Gamma ray beams to destroy the cancerous tissues or tumor area. The high energy radiation helps in curing cancer by stopping its growth and spread. Alternately, Radiation Therapy also provides relief from pain and bleeding due to cancer. 60 – 75% of all cancer cases require Radiation Therapy either as a curative or palliative procedure or a form of therapy at some or the other stages of treatment.
3DCRT: 3-DIMENSIONAL CONFORMAL RADIATION THERAPY
The treatment planning system conforms to the 3D shape of the tumor using multi-leaf collimators that shapes the beam. This delivers very precise and optimal dose to the tumor and spares the surrounding normal tissues to the maximum.
IMRT: INTENSITY-MODULATED RADIATION THERAPY
This is a specialized form of 3D CRT, where each radiation beam is subdivided into many tiny ‘beamlets’. The intensity of each of them can be varied individually, thereby effectively delivering the radiation dose more precisely to the target while further limiting the dose to the surrounding normal tissues.
IGRT: IMAGE-GUIDED RADIATION THERAPY
This refers to the use of sophisticated imaging technologies to guide the delivery of Radiation Therapy more precisely. Tumors can move during treatment and between treatments. For dynamic targeting IGRT, the LINAC is outfitted with sophisticated imaging devices. It helps in targeting the tumor more precisely sparing surrounding normal tissues and allows for dose escalation to the target, improving chances of cure
Volumetric Arc Therapy (VMAT) or RapidArc® Radiotherapy Technology is an advanced form of Intensity Modulated Radiation Therapy (IMRT) that delivers a precisely-sculpted 3-Dimension dose distribution with a 360-degree rotation of the gantry in a single or multi-arc treatment.
Stereotactic Radio Surgery / Radiation Therapy (SRS / SRT) (Intra-cranial / Extra-cranial) SRS / SRT is a highly specialized non-surgical procedure that uses highly focused X-ray (also called- X-knife) beams to converge on the tumor/ abnormality with very high level of precision and accuracy (with the help of micro-MLC) to deliver a high dose of radiation. It can be done with a localization frame fixed to the skull or can be frameless (intra-cranial) or even with a Stereotactic body-frame (SBF) device (extra-cranial). SRS delivers a very high radiation dose in a single session, while SRT is delivered in multiple sessions. In SBFRT again a relatively higher dose of radiation is delivered per fraction for a few sessions spaced out in time. Many benign lesions/ tumors of brain, cranial metastatic lesions, arteriovenous malformations (AVMs) are treated with SRS/ SRT. Metastatic lesions in various organs (like lungs, liver, very close or involving spinal cord etc), and even some locally advanced inoperable primary tumors can be treated with SBFRT. Difficult to treat lesions lying very close to critical structures such as spinal cord, brainstem, optic apparatus can be treated with Intensity- Modulated Radio surgery (IMRS).