Image Guided Radiation Therapy
Image Guided Radiation Therapy is a technique which involves the frequent use of diagnostic imaging to view the location, extent and size of the tumor during the course of the radiation therapy. This not only enhances accuracy and precision of the treatment, but also plays a critical role in the post therapy management of the patient.
In the Image Guided Radiation Therapy, the machine that delivers the radiation dose (i.e. linear accelerator) is linked to any diagnostic imaging equipment like a Computed Tomography (CT scan) Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET scan) or simply an X-ray, via a computer program, which facilitates the physician to view the tumor before, during and after the irradiation. This allows the radiation specialist to make necessary corrections and adjustments during the patient's exposure to the radiation doses.
Who can Undergo Image Guided Radio-Therapy (IGRT) Breast Cancer:
Breast cancer is usually diagnosed in early stages and in many cases of breast cancer, the breast can be preserved. In preservation of the breast, the cosmesis should be maintained. The radiotherapy of the breast involves the irradiation of the whole breast and higher dose to the tumour bed. But at the same time the lung and the heart are also irradiated.
Since these patients are going to be the long term survivors, the late toxicities of radiation need to be minimised. Lungs and heart being mobile organs, Image Guided Radio-Therapy ( IGRT) can be solution to overcome their mobility.
Prostate Cancer: Prostrate Cancer can be treated very well with high dose of radiation. Since prostrate is surrounded by two critical organs, the rectum and the urinary bladder, radiation becomes a critical issue. Also, position of the prostrate varies with the bladder filling and to an extent, distension of the rectum. With Image Guided Radio-Therapy ( IGRT), these volumes can be reduced, so that a higher dose of radiation is delivered to the tumour and minimising the dose to bladder and rectum.
Brain tumors: The brain is enclosed in the compact cranial cavity and brain does not move on its own within this cavity, but the irradiation volumes are very prone for set-up errors and this is very risky. The movements of neck and chin can alter the position of targets within the cranial sphere to a large extent. The margins of the treatment volumes are kept very tight to save the normal brain and other critical structures and the gradient between the high dose and low dose at the periphery of tumour volume is very sharp. These errors can be minimised with Image Guided Radio-Therapy ( IGRT).
Lung Cancer: Statistics say that more 60% of the times, lung cancer is detected in advanced stages, when the in which radiotherapy and chemotherapy is the standard of care. To achieve the outcome of radiation therapy with minimal side- effects, it is imperative to administer a radical dose of radiation to the tumor. Since lungs move with respiration, higher volume of radiation is given so as to not miss out the tumor, thus irradiating the normal lung. Image Guided Radio-Therapy ( IGRT) is advantageous in such cases to save the healthy tissues in the lung.