Importance of IMRT
In our body thousands of cells break down every day and get replaced by new cells, to keep the body optimum. All effective medicines damage or kill some more cells in the body which are effectively replaced. Radiation therapy, when it came into existence, was primitive. It would hurt the normal cells, more than the body could replenish, and side effects would affect the quality of life in cured patients.
However, radiation was here to stay by the year 1934; as one of the scientific forms of therapy in cancer with its ability to disrupt the DNA of cancer cells far more than the normal cells with a significant cure rate. Before the turn of this century, we were able to modify the way radiation was delivered conforming to the general shape of cancer (3 Dimensional Conformal Radiotherapy - 3DCRT).
With the improvement in computers by leaps and bounds, in this century we can modulate the radiation delivered into any irregular shape within the body. This revolutionary technology is Intensity Modulated Radiotherapy (IMRT) and became the basis for all subsequent developments.
With the irregular shapes achieved the IMRT dose of radiation fits in three dimensions into the corresponding irregular shape of cancer spread. IMRT technology reduced the number of normal cells damaged phenomenally, and side effects have come down very dramatically.
Difference between IMRT and IGRT
With the sophisticated treatment, came the need for very precise positioning while on treatment. Earlier positioning with measurement was replaced by imaging taken with the treatment machine itself. During the treatment with IMRT x-ray images are taken to check the position of the patient on the treatment table and exact corrections made. In Image-Guided Radiotherapy (IGRT), CT scan is taken with the treatment machine, and the same IMRT treatment is delivered. There is no difference between IMRT and IGRT in terms of tumour control and cure; however, with IGRT probability of side effects is expected to come down. If one needs to optimize the finance, could go for IMRT unhesitatingly and makeup with the more rigorous lifestyle changes. Of course, 3DCRT is, even today, used for more straightforward treatments.
IMRT and IGRT at CTI
At CTI, we use an advanced, top-of-the-linear accelerator machine, Varian True Beam STx with 6DoF (6 Degrees of Freedom therapy table) Robotic Positioning system. After the patient lay down on the couch and images, 3D match is done for six directions (in technical terms: up-down, left-right, vertical, rotation, yaw and pitch), both for IMRT and IGRT.
Varian TrueBeam STx with 6DoF machine is also a top-end machine for Radiosurgery {read more}.
DIBH
Radiotherapy today has improved by leaps and bounds over decades and is now sophisticated technology helped by robotics and AI. In the left-sided breast cancer therapy, since the heart is nearer to the treatment area, another sophisticated method - Deep Inspiratory Breath Hold Technique (DIBH) - is used. DIBH shifts the heart away (heart becomes more vertical during the deep breath position and moves away from the chest wall) from the treatment beam. It requires about 3 to 5 deep breath positions to treat, and it takes less than 10 minutes to complete this automated technique, in our centre, with the availability of True beam technology. DIBH is a straightforward technique and requires minimal practice.
The second situation where DIBH is used is in the chest and upper abdomen radiotherapy and Radiosurgery. Here the lumps move in a complex trajectory during breathing. Since a superior dose is delivered with SABR in a short period of time, far higher precision is required. One way is to track the tumour breathing movement during the radiation process. The other way is "freeze" the tumour in a particular position as the treatment is going on. Today's technology permits that, and the patient is asked to take a deep breath and hold it for 10 to 20 seconds, and radiation therapy gets triggered during this phase. Also, treatment beams converge from many directions focusing on the cancer tissue. The whole process is precise to the level of less than an mm, automated, images and confirmed with Varian TrueBeam STx with 6DoF.
Another great advantage of the Varian TrueBeam STx with 6DoF is that the actual treatment gets over in 2 to 3 minutes. Concise duration treatment is possible with another evolution, i.e. development of flattening free filter (FFF or Triple F) technology.
4D CT Scan Technique
The first choice for lung and upper abdomen Radiosurgery is DIBH. However, when the deep breath-hold is not possible, then using the 4D CT scan technique, the tumour will be targeted at a particular phase of the breathing cycle. This technique is also handy in patients who do not want to undergo the invasive gold seed insertion (around the tumour) into the lung.
Another technique during liver SBRT is an abdominal compression technique to "freeze" the tumour without any movement.
Note: Each clinical scenario is different. Sometimes it is essential to check the most suitable techniques mentioned above, i.e. DIBH, 4D CT scan, Gold seed fiducial tracking or abdominal compression technique to find out which suits the best for that particular clinical situation. That's what we precisely do.
Other Facilities
The other facilities available in our centre are Electron Beam therapy, Total skin irradiation, Total Body Irradiation (TBI) for Bone Marrow Transplant (BMT), Hemi-Body Irradiation (HBI), Radiation Lung Bath, Hemi-thorax radiation, Whole Abdominal Radiation (WAR), Cranio-Spinal Radiation, Low-Dose Fractionated Radiation (LDFRT) etc.
We have expertise in SABR/SBRT as "Bridge to Liver Transplant", Concurrent Chemo-radiation, Neoadjuvant and Adjuvant radiation, Single-dose radiation, Hippocampus-sparing whole brain radiation, Malignant Pleural Mesothelioma (MPM) radiation, "Beam Hold Technique" fiducial tracking in carcinoma prostate SBRT etc.
Cancer therapy India is one of the best hospital for radiotherapy in India having the best radiation oncologist in India who work together in areas of expertise to provide the best radiation therapy in Bangalore and the highest level of patient care. Cancer Therapy India is among the best radiation hospital in Bangalore and their multidisciplinary team of radiology experts offer the best radiation therapy in India and work best to help keep you strong during and after treatment.
