Lymphoscintigraphy

The lymphatic system is a network of small channels, similar to arteries and veins, that transport the fluid and cells of the immune system to and from the lymph nodes and throughout the body.

This fluid, called lymph, normally flows slowly from the arms and legs toward the center of the body and into the blood stream.

If the flow of lymph is blocked, the fluid can build up and the affected areas can become swollen.

Lymphoscintigraphy is a special type of nuclear medicine test that provides images of your child's lymphatic system.

We use lymphoscintigraphy to evaluate children and adults who may have several different conditions:

• swelling (edema) of the arm or leg, called lymphedema
• chylothorax (lymphatic fluid collecting in the cavity around the lungs), sometimes as a result of a lymphatic or vascular anomaly or after thoracic surgery
• certain types of cancer, to identify and examine the lymph node closest to the tumor — called the “sentinel node” — to see if the cancer has spread

We perform lymphoscintigraphy using a gamma camera — a specialized camera that detects radiation and takes pictures from different angles. A computer helps create the images from the data obtained by the camera.

• The nuclear medicine technologist will ask your child to lay down on an examination table, and will inject a very small amount of radioactive tracer (or radiotracer) into your child’s skin using four very small needles.
• The radiotracer will travel into your child's lymphatic system, where the technologists can detect it with the gamma camera.
• Immediately after the injection, the technologist will take a series of images with the gamma camera. While the camera is taking pictures, your child will need to remain still for brief (three to five minutes) periods of time.
• In some cases, we may move the camera very close to your child's body to get the best possible images. The camera will never actually touch your child.
• If your child is having lymphoscintigraphy before surgery to find a sentinel lymph node (a node into which all of the lymph fluid from a particular area of the body drains), your child’s surgeon also may use a small probe that looks like a microphone to detect and measure the amount of radiotracer in a small area of your child's body. This will help the physician find the lymph node.
• The nuclear medicine physician may ask you and your child to return for additional pictures throughout the day.

While the injection can cause some discomfort — it might feel similar to a bee sting — the imaging process itself is completely painless.

We use a topical anesthetic to reduce the pain of the injection.

Nuclear medicine has been used on babies and children for more than 40 years with no known adverse effects from the low doses used.

• The radiopharmaceutical contains a very tiny amount of radioactive molecules. Those molecules will pass out of your child's body before the end of the day. We believe that the benefit to your child's health outweighs potential radiation risk. Learn more.
• The camera used to obtain the images doesn’t produce any radiation.
• It is safe to be with your child in the imaging room if you are pregnant or nursing.

Boston Children's is committed to ensuring that your child receives the smallest radiation dose needed to obtain the desired result. You can find out more here about what we're doing to keep nuclear medicine and radiology scans as safe as possible.

Yes. We encourage you to stay with your child during the entire procedure, though other children are not allowed in the procedure room.

Here are a few tips that may make the procedure easier for your child.

• There are no restrictions on eating or drinking before the scan.
• We suggest giving your child a simple explanation as to why lymphoscintigraphy is necessary and assure her that you will be there for the entire time.
• You may want to bring your child's favorite book, video, toy, or blanket to help her stay still during the test and pass the time in between scans.

Getting a lymphoscintigraphy scan can sometimes be a little intimidating for small children — that’s why we’ve set everything up to be child-friendly. We place a great deal of importance on making sure children and their families are well informed about the procedure in advance, so that they know what to expect.

One of our child life specialists may also be available to help your child during the examination, using age-appropriate play and other distraction techniques.

No. Because lymphoscintigraphy just involves small injections and taking images, and because children only have to remain still for brief periods of time while being scanned, we don’t use sedation for most children.

Our technologists and child life specialists are good at helping children and families remain comfortable through procedures like lymphoscintigraphy. It’s because of these specialists that we so rarely need to sedate a child to perform lymphoscintigraphy — eliminating the inherent risks of anesthesia, especially in young children.

When you arrive, please go to the Nuclear Medicine check-in desk on the second floor of the main hospital. A clinical intake coordinator will check in your child and verify her registration information.

Then you’ll meet with one of our nuclear medicine technologists, who will explain to you and your child what will happen during the procedure.

You should plan on being here for most of the day. It may take some time for the radiotracer to move throughout the lymphatic system.

Not all the time is spent in the examination room, though. In between imaging sessions, you and your child can wait in the waiting room, take a walk, or go to the cafeteria. Just be sure to return to Nuclear Medicine in time for any additional imaging.

• The nuclear medicine physician will have you come back several times (at intervals of a few hours) so that she can take more images.
• Sometimes, the doctor may ask your child to walk around to speed up lymphatic flow.

One of Boston Children's nuclear medicine physicians will review your child's images and create a report of the findings. We will send the report to the doctor who ordered your child's scan. Your child's doctor will then discuss the results with you.

In the meantime, unless your physician tells you otherwise, your child may resume normal activities immediately after the scan.