Radiation therapy is the use of beams of energy to treat tumors.
Doctors first figure out the precise location of the tumor using computed tomography (CT) and magnetic resonance imaging (MRI) scans. Then they use special machines to aim X-ray or proton beams at that site from several angles.
The beams can travel through outer structures, such as skin and bones, to reach the depth of the tumor and kill the tumor cells there.
The technology for this type of treatment has changed remarkably in recent years, even in just the past five years.
Now, doctors are able to target tumors better and to spare healthy areas or limit damage to them. This means fewer side effects for children in the short term and the long term.
Some children with neuroblastoma may be able to have a newer type of radiation therapy called I-131-MIBG therapy. This is a way to get radiation inside your child’s body and into their cancer cells via the bloodstream.
Types of Treatment
Some types of radiation machines may send out beams wider than the place where your child needs treatment. So doctors use blocks inside the machine to stop segments of the beam that would otherwise hit healthy tissue.
Other types of machines emit more focused beams and may be right for certain types of tumors or tumor sites.
We offer different types of radiation therapy:
Three-dimensional conformal radiotherapy
This was the standard for many years and is still useful in many situations. It focuses two or three X-ray beams on the tumor site.
This is becoming more common. It allows doctors to use more X-ray beams and to focus them in a more precise way to confine the radiation to the tumor.
Fractionated stereotactic radiotherapy/radiosurgery
This can focus X-rays even more precisely and is good for certain types of tumors in the head, such as craniopharyngiomas, pituitary adenomas, retinoblastomas and other small brain tumors. It helps spare normal brain tissues. It can also be used to treat some problems with the blood vessels. Sometimes this is called gamma knife therapy.
This type uses protons instead of X-rays, so it’s even more precise. Protons stop once they reach their target, reducing radiation effects to healthy tissue beyond the target. Read more.
What is a typical radiation therapy schedule?
Most children who get radiation come for treatment each day, Monday through Friday, for several weeks. The treatment itself takes about 5 to 10 minutes per session, but the total time at the center is typically 30 to 90 minutes each day.
Where Treatment Happens
Most of our young patients get their radiation treatment in the Cancer Center at University of Washington Medical Center, which has a pediatric radiation therapy service. Gamma knife therapy is performed at Harborview Medical Center. Proton therapy is offered at SCCA Proton Therapy, A ProCure Center, on the campus of Northwest Hospital & Medical Center in north Seattle.
To keep the beams aimed at the right spot, children must be very still during treatment. Most children younger than 5 years of age get anesthesia before each radiation treatment.
When a child needs this sedation, a pediatric anesthesiologist from Seattle Children’s goes to the University of Washington Medical Center, Harborview or SCCA Proton Therapy, A ProCure Center.
Finding Out What Your Child Needs
Each week our doctors from various specialties, such as medicine, surgery and radiation, meet at our General Tumor Board and our Brain Tumor Board.
These meetings provide a time when our team can talk as a group about each patient and develop treatment plans. Your child's doctors will discuss whether radiation is a good treatment choice for your child and will let you know what they recommend.
Dr. Ralph Ermoian, a radiation oncologist, attends both boards to help the teams assess whether radiation may be helpful.
Here are the steps you can expect if your child needs radiation:
- If we think your child needs radiation therapy, we will ask you to come see us to talk about the reasons, the benefits and the possible side effects.
- If you agree that radiation is a good treatment for your child, we will have a second meeting for detailed treatment planning. We will do a CT scan of the tumor site to tell right where the tumor is, and we will figure out how we want to carry out the sessions. This is called a simulation.
- Next, we will take one to two weeks for technical work to figure out the best angles for treatment and to set up the equipment.
- If your child needs anesthesia before treatment, the next step is to come in for the first radiation treatment. First, we will give your child anesthesia. Then we will do a “dry run” with your child to make sure everything is set properly. Once we confirm all settings are correct, and while your child is under anesthesia, we will give the first dose of radiation.
- If your child does not need anesthesia, we will still do the “dry run.” Then we will have your child come back for the first treatment a day or two later.
What's Special About the Radiation Therapy Service at Children’s?
Children’s provides multidisciplinary care. We bring together teams of experts from many fields to decide, with you, the best treatment plan for your unique child. This includes our use of radiation.
Dr. Ermoian is the only radiation oncologist dedicated to pediatric care in Washington, Wyoming, Alaska, Montana and Idaho. He has a unique depth of knowledge about cancer care and about the experiences of children with cancer and their families.
He is one of many team members who work to make sure our radiation therapy service focuses on the special needs of children.
We have a full-time nurse dedicated to caring for our patients who come for radiation therapy a pediatric recovery room.
SCCA Proton Therapy, A ProCure Center, is the first and only place to offer proton therapy in the Northwest. The Seattle Cancer Care Alliance (SCCA) brings together cancer care from Seattle Children’s, UW Medicine and Fred Hutchinson Cancer Research Center.
Who Needs Radiation Therapy?
About 50% to 60% of our young cancer patients get radiation. Most get radiation in addition to surgery and chemotherapy.
Some types of tumors respond well to radiation, and others do not. So it is not the right choice for all our young patients.
We use radiation most often to treat brain tumors and sarcomas (bone tumors), and we use it to prepare patients for a hematopoietic cell transplant.
We also use radiation for children with Wilms tumors, a type of kidney tumor; neuroblastoma; some cases of leukemia; and some other forms of cancer.