Intensity Modulated Radiation Therapy (IMRT)

Intensity modulated radiation therapy (IMRT) is a specialized form of 3D-CRT that allows radiation to be more exactly shaped to fit your tumor. With IMRT, the radiation beam can be broken up into many “beamlets,” and the intensity of each beamlet can be adjusted individually. Using IMRT, it may be possible to further limit the exact amount of radiation that is received by normal tissues that are near the tumor. In some situations, this may also allow the safe delivery of a higher dose of radiation to be delivered to the tumor, increasing the chance of a cure.

Advantages of IMRT

IMRT can treat a wide range of cancer cases anywhere in the body. Whether you have a benign tumor you’d like to get ahead of or a difficult case that needs a customized treatment, IMRT may be what your doctor recommends. IMRT is highly precise and shapeable, meaning it can match the shape of your cancer exactly and deliver the radiation directly to the target area as efficiently as possible. Even the dose of radiation is customizable with IMRT.

This precision in both dose and targeting lowers the risk of hurting nearby healthy tissue, minimizing side effects from the cancer treatment as your body recovers. Overall, IMRT can lead to a better outcome for your case, no matter its complexity.

How IMRT Works

IMRT beams are called “beamlets,” and can be individually adjusted. Each beam in a single treatment can have its intensity varied, allowing for a higher dose delivery to more malignant tumors. The beams are delivered by a medical linear accelerator (LINAC), a large machine that the patient must lie still under.

CT scans or X-rays may be used in order to correctly position the patient on the treatment table. Marks made on the skin will be used as a guideline for where the beams need to be delivered. Charlotte cancer treatment sessions can take around 30 minutes, during which time the patient may be repositioned to ensure correct targeting of their cancer tissue.

Cancers Treated with IMRT

IMRT is a possible treatment for a vast array of people with different cancers thanks to its customizable nature. In particular, IMRT is used as a treatment for:

The IMRT Treatment Process

Patients undergoing IMRT can expect a comfortable treatment process, all guided by expert Charlotte cancer doctors at SERO. Support services and educational materials can always be provided by our team to keep you and your family at ease. We prioritize information and updates for you each step of the way, including care instructions after active treatment has concluded.

Before IMRT can be administered, you will have a diagnostic evaluation, which often includes imaging studies like CT scans, MRI, or PET scans. Your team will then define the target area, which includes the tumor and any nearby lymph nodes or areas at risk of containing cancer cells.

Your radiation oncologist will then optimize the radiation dose distribution, so the highest possible dose can be delivered while keeping nearby healthy tissue safe. IMRT achieves dose optimization by dividing the radiation beams into numerous small beamlets, whose intensity can be adjusted individually.

During a session, you will be carefully positioned on the treatment table, often with immobilization devices to ensure precise targeting. The LINAC will deliver carefully customized beams of radiation according to the treatment plan devised with your doctor.

Typically, a patient will undergo IMRT for several days in a row each week for several weeks. After the treatment is complete, follow-up visits for monitoring will be scheduled to assess treatment response and monitor for potential side effects.

Side Effects of IMRT

The side effects of IMRT primarily depend on the area treated, but generally, these side effects may be experienced after treatment:

  • Fatigue
  • Swallowing irritation
  • Nausea/digestive changes
  • Bowel/bladder changes

There can also be certain permanent side effects of IMRT, which can occur even in the years following treatment. You should always discuss potential risks and side effects with your doctor when making a decision about what treatment type is right for you.

Frequently Asked Questions (FAQs)

Is IMRT suitable for all types of cancer?

IMRT is suited for many types of cancers, given its precise nature and ability to treat cancer at all stages. However, many factors go into deciding which cancer treatment is right for you, and should always be discussed with your doctor.

How long does an IMRT session last?

One IMRT session typically lasts 10-30 minutes, though for complex cases, it may go up to an hour.

How is IMRT different from other radiation therapies?

IMRT is a form of external beam radiation therapy (EBRT), but is more specialized. IMRT’s customizable beamlets make it unique. Image-Guided Radiation Therapy (IGRT) is another larger term that applies to IMRT and includes EBRT as well. It simply refers to the fact that X-rays, CT scans, or MRIs may be used to position the patient properly for treatment.


SERO is made up of radiation therapy experts dedicated to effective and personalized treatment for your cancer. If you think IMRT is the right treatment option for you, contact us today at 704-333-7376 or schedule a consultation online.

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