Image-guided Radiation Therapy

What Is Image-Guided Radiation Therapy (IGRT)?

Image-guided radiation therapy, or IGRT, is a type of cancer treatment that combines the use of visual imaging with high-energy X-ray or proton beams to destroy tumors. There are several technologies involved, but all of them utilize detailed images of cancerous growths and the surrounding tissues taken before and sometimes during the procedure. This allows the medical team to more precisely deliver the radiation dosage and also to locate tumors that tend to change position. Patients receiving IGRT undergo a simulation beforehand; this is a practice run for the actual procedure in which the areas of the body to be dosed are carefully mapped out. 

Technologies used in IGRT include imaging machines, computer software, and radiation-delivery systems. Imaging technologies consist of X-rays, ultrasounds, computed tomography (CT), and magnetic resonance imaging (MRI).

Doctors use imaging tests to precisely locate and measure the size and shape of a tumor. Computer software compares the reference images. A linear accelerator then delivers targeted radiation to tumors while avoiding healthy tissue.

IGRT is now viewed as the standard of treatment for radiation therapy. It can be used with a wide range of cancers more effectively than older forms of radiotherapy without imaging. To learn more about cutting-edge cancer treatments, see the oncology providers at Baptist Health. 

Why Is Image-Guided Radiation Therapy (IGRT) Used to Treat Cancer?

Image-guided radiation therapy offers several advantages in treating cancer over earlier versions of this method. With IRGT:

  • Physicians have a clearer picture of the size, location, and extent of the malignancy
  • Radiation dosages are more accurately delivered
  • Less damage is inflicted on healthy, surrounding tissues
  • Cancer is more effectively controlled because higher dosages are utilized
  • Treatment is possible for cancers sitting near sensitive organs or tissues

IGRT also enables better tracking of tumors that move, based on organ function or tissue structure. Examples include cancers of the lungs, prostate, pancreas, and liver. 

Preparing for IGRT

Your doctor may recommend various ways for you to prepare for IGRT. Doctors may inquire about potential pregnancy or breastfeeding. Pregnant women, females who think they may be pregnant, and women engaged in breastfeeding should inform their doctors prior to IGRT.

Your doctor may also ask about pacemakers or any metal in your body from other surgeries. For example, if you use a pacemaker, please inform your doctor. Any metal in your body can impact an IGRT.

If you have prostate cancer, your doctor will likely ask you to consume enough water to fill your bladder an hour before your procedure. A full bladder allows your doctor to image your prostate more easily with an ultrasound. 

What Can I Expect During Image-Guided Radiation Therapy (IGRT)?

An image-guided radiation procedure typically entails the following steps:


The first step in a radiation procedure is called a simulation, in which your medical team will prepare you for the actual procedure at a later date. Simulations increase the effectiveness of cancer treatment by pinpointing the exact location for delivering the radiation dosage. 

On the day of your appointment, you will go to the hospital or other medical facility where the simulation is scheduled to take place. You will change into a hospital gown and go to a room with a table and medical-imaging equipment. There you will undergo a variety of scans all with the purpose of locating the tumor or tumors and determining the best approaches for dosing. Your medical team may position you in a series of molds or frames, to obtain the best possible views for the scanners. At the end of the procedure, your body will be marked to indicate the target points for radiation treatment.

Medical-imaging technologies, such as X-rays or CT scans, are utilized during a simulation. You will be able to schedule the first of your radiation treatments when the simulation is completed. 


Treatment is similar to simulation but typically shorter in duration, because your medical team will already have a plan in place for the procedure. You will return to the medical facility, change into a gown, and go to a treatment room with a table and both radiation and imaging technology. A member of your medical team will position you, according to the findings of the simulation. The actual dosing may take up to two hours. Your radiologist will monitor you throughout this period, using the imaging equipment to fine-tune delivery, based on any changes in the location of the tumor. The actual procedure is painless. 

Depending on the type and severity of your cancer, you may return to the facility to receive additional treatments. Your medical team will keep these trips to a minimum by precisely targeting maximum dosages of radiation. This is a major advantage of using image-guided radiation therapy, and one reason why it’s more effective than the older method. 


Both during and following radiation therapy, you will have regularly scheduled follow-up appointments. These will help ensure that your treatments are effective, as well as address any side effects that you may experience from radiation. 

What Are the Side Effects of Image-Guided Radiation Therapy (IGRT)?

IGRT can result in both short- and long-term side effects. Short-term effects can begin almost immediately after treatment and last a few weeks.

They include:

  • Weakness and fatigue
  • Irritated, itchy, or swollen skin
  • Hair loss
  • Headaches
  • Changes in appetite
  • Nausea
  • Changes in bathroom habits
  • Diarrhea

Long-term side effects are less common but more serious. They become apparent months or sometimes years after treatment:

  • Infertility
  • Lymphedema
  • Secondary cancers

Radiation therapy can also lead to changes in the size, shape, or functional effectiveness of targeted organs or structures. For example, radiation for brain tumors has been linked to the development of cataracts, hearing loss, and memory loss, some of which may be permanent.

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