IMRT – Intensity Modulated Radiation Therapy

Techniques of Radiation therapy for cancer treatment

There are major advances in techniques of radiation therapy which all lead to precise focused for of radiation therapy which is associated with high cure rates with reduced side effects.


IMRT stands for intensity modulated radiation therapy. In this technique intensity of radiation is modulated/modified in such a manner that it gets concentrated on cancerous area with least doses to surrounding healthy tissues.

VMAT and Rapid arc are delivery techniques of IMRT which help in further improving precision of IMRT as well as require shorter treatment delivery time every day.


IGRT stands for Image Guided Radiation Therapy. IGRT is a combination of IMRT with Image guidance. For patients undergoing IGRT, treatment is planned with IMRT or VMAT.  Additionally, before starting radiation treatment, daily a short CT scan called Cone Beam CT (CBCT) is taken on radiation machine (Linear Accelerator). Everyday this CBCT is matched against planning CT scan to verify accuracy of patient positioning and target. In simple words IGRT further improves accuracy of radiation therapy over IMRT.


SBRT stands for stereotactic body radiation therapy.SBRT is a technique of radiation therapyin which still higher degree of precision is used for certain specific of lung cancer, liver cancers, bone and lymph node metastases. SBRT gives high ablative dose of radiation in fewer sittings of treatment.


SRS stands for stereotactic radio surgery and radiotherapy. SRS and SRT techniques are used for targeting brain tumours or metastases with high accuracy of stereotactic localization. SRS and SRT gives high dose of radiation in fewer sittings of treatment.

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