Difference Between IMRT and IGRT

Difference Between IMRT and IGRT

Cancer is an extremely complicated disease, which makes it very difficult to battle. Fortunately, cancer treatment has come a very long way in the past 100 years or so. That isn’t to say cancer isn’t a very challenging battle anymore, though, because it certainly is.

If you or a loved one is dealing with cancer, then you are probably used to hearing acronyms with all of the abbreviated medical staff, medicines, treatment, diseases, etc. However, you are probably a lot less used to what knowing exactly what all of those acronyms stand for.

Since cancer is already such a difficult battle and a very complicated disease, you don’t need the extra stress of being confused by acronyms. There are plenty acronyms involved with cancer treatments that can be very difficult to distinguish, especially when they’re extremely similar. For instance, IMRT and IGRT are not only very similar acronyms, but they are similar forms of radiation therapy.

Although they may be similar, they are very different too, and it is extremely important to understand what makes them different from each other. If you don’t know the difference, then don’t panic – we have the answer for you right here:

IMRT = Intensity-Modulated Radiation Therapy

Radiation therapy previous to IMRT had one major limitation – it could only fit to a general tumor shape without conforming to the exact shape and surface of the tumor.

However, with IMRT, the computer uses a 3-D image of the malignant tumor and its irregular shape. Then, using the computer image, this mode of high-precision radiotherapy uses computer-controlled linear accelerators to deliver extremely accurate radiation doses that conforms to the tumor, or specific areas within the tumor, in a much more precise manner that previously achieved.

Additionally, by being able to control, or modulate, the intensity of the radiation beam in multiple small volumes, IMRT further allows for a precise delivery of radiation doses. Being able to modulate the intensity increases the likelihood of the doctors being able to cure the cancer as it can provide a higher dose of radiation to areas with a higher concentration of cancer cells. This also helps the doctors minimize damage to the adjacent areas with healthy tissues and organs decreasing the risks of side effects significantly.

IGRT = Image-Guided Radiation Therapy

Tumors often move between treatment sessions due to things such as breathing and changes in organ-filling. Additionally, patients tend to alter their positioning between separate treatments, which affects where the tumor is relative to the radiation beam accelerator.

While Radiation Oncologists used to only use external beam radiation therapy, like IMRT, by way of very precise mathematical location without being able to exactly see the tumor, the higher doses of concentrated radiation require that you know exactly where you’re provided the dose to. So, new technology came about that can account for this issue – IGRT.

IGRT uses Cone-Beam CT images to track the changes in the position of the tumor to more accurately pinpoint where the radiation doses should target. So, in addition to all of the benefits described when using IMRT, image-guided radiation therapy also allows Radiation Oncologists to better deliver the radiation, making the therapy more accurate, more effective, and safer than many other techniques.

At the end of the day, it is important to remember that you will be under the direct supervision and guidance of a doctor, or team of doctors, that are there to help you through the process. You will most likely meet with them at least once per week to assess your progress while undergoing a certain treatment.

It is also very important to understand not only the advantages to each treatment technique, but also to understand the risks associated with them. You can read about the side effects of IMRT or the side effects of tomotherapy (a form of IGRT), or don’t be scared to take the opportunity to let the doctor know about any possible concerns you have while undergoing a certain treatment.

Battling cancer is a very tough experience, and understanding what’s going on might help a little with the stress, which can make a huge difference – so, don’t be hesitant when it comes to asking for help! 

By Russell McBurnie