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Total Lymphatic Irradiation

What is TLI?

Total lymphatic irradiation (TLI) is radiation therapy given to the lymphatic system. TLI uses high-energy x-rays. TLI is an important part of some stem cell (bone marrow) transplants.

The lymphatic system is part of your immune system. Normally, having a strong immune system is good. But the immune system can also attack the new, healthy donor cells your child gets in a transplant. TLI helps turn off the immune system for a short time, so it will not harm the new cells.

Doctors use chemotherapy and TLI together to prepare for the transplant. TLI may occur before, during, or after chemotherapy. It usually includes 4 doses.

Diagram of total lymphatic irradation (TLI)

Total lymphatic irradiation (TLI) is radiation therapy given to the lympathic system.

Getting Ready for TLI

Pre-Treatment Evaluation

About 1-2 weeks before TLI, you will meet with a radiation oncologist (a cancer doctor who specializes in radiation therapy). The radiation oncologist will explain TLI and discuss the benefits and potential side effects.

You will also meet other care team members. These include nurses, child life specialists, and radiation therapists (the people who give the TLI treatments). Your health care team will ask a parent or guardian to sign a consent form to give permission for TLI. The care team will let you know what to expect and answer your questions.

Simulation Visit

A simulation visit is a planning visit to help your child get ready for the actual treatment. During this visit, your care team will plan the radiation treatment and explain the process to you and your child. This visit can take up to 2 hours.

Your team will make a plastic mesh mask and a headrest to help your child stay in position during treatment. Then, your child will have a computed tomography (CT) scan in the treatment position.

A CT scan uses X-rays to create pictures of the inside of the body. The images from the CT scan will help plan the TLI treatment. Your doctor may use CT contrast for planning. The contrast highlights certain areas of the body to see them better on the CT scan.

During the simulation visit, your child will probably get 4-6 small permanent tattoos on the skin. These tattoos are about the size of a pencil tip, and they help mark the correct position for treatment.

The radiation therapist might also draw some lines on your child’s body with a marking pen. These are not permanent but help mark the correct treatment position. Please do not wash off these marks until your child is done with treatment.

What to Expect during TLI

Your child will not feel anything during TLI treatment. The machine might make a humming sound or other noises.

The radiation therapist will ask your child to lie on the radiation table using the mask and headrest. While receiving radiation, your child must be very still.

You may bring your child’s favorite music playlist or audiobook to play during the radiation treatments. Encourage your child to relax and breathe normally during treatment.

Your child will be alone in the treatment room during TLI when the machine is on. The radiation therapist will watch on the TV monitor and can see, hear, and talk to your child.

The total time for the TLI treatment is about 30 minutes. After treatment, there is no radiation in your child’s body or on their clothes. Your child is not radioactive and is safe to be around. Your child will go back to their hospital room after treatment.

Side Effects of TLI

Your child might have one or more of the side effects listed below. Because TLI is given as part of other treatments, it is hard to know if a side effect is caused by radiation, chemotherapy, or other treatments. Most side effects of TLI go away after treatment is over.

Side effects are called “early” or “late,” depending on when they happen after the start of treatment.

Possible Early Side Effects of TLI

Early side effects can happen shortly after the start of TLI and up to 6 months after TLI ends. They include:

Possible Late Side Effects of TLI

Late side effects can happen 6 months or longer after TLI. They can include:

  • Changes in normal growth and development
  • Having fewer than normal of certain types of blood cells
  • Changes in the function of the heart, lungs, liver, or kidneys
  • Hormone problems
  • Infertility (trouble getting pregnant or fathering a child)
  • Other cancers

Taking Care of your Child During TLI

Follow these tips to help take care of your child during TLI:

  • Remove jewelry and contact lenses for TLI. Your child can wear them between treatments.
  • Give medicines as instructed to control nausea and vomiting.
  • Do not wash off any pen marks used for positioning or shielding until the TLI treatments are over.
  • Do not use oil-based creams or lotions on the days of TLI. Some lotions can interfere with treatment. Use only lotions that are ordered by the care team until the last treatment is over. Then, use creams or lotions as recommended to keep the skin soft and moist.
  • Take care of the skin. Use mild soaps, such as Dove® or Ivory®. You may use the soap provided on the transplant unit for bathing. Avoid deodorant soaps. Do not use hot blow dryers on the skin or scalp.
  • Your child’s skin will be sensitive to sunlight and will burn more easily now and in the future. Always use sunscreen with 30 SPF or higher and limit sun exposure when possible.

Key Points

  • Total lymphatic irradiation (TLI) is radiation therapy delivered to the lymphatic system.
  • TLI may occur before, during, or after chemotherapy as part of conditioning to prepare for a stem cell transplant.
  • TLI is painless, but some patients may have side effects after TLI. Most side effects occur within days or weeks after treatment and go away over time. However, some side effects can occur later or be long-lasting.
  • Talk to your care team about any problems or questions.

Reviewed: July 2022