Radiation Simulation

What is radiation simulation?

Radiation simulation is a practice radiation therapy session. It helps your care team plan your child’s radiation treatment.  

During radiation simulation, the radiation oncologist chooses the best position for your child’s body. The correct position helps the treatment work better and helps protect healthy cells.  

Getting ready for radiation simulation

Meet the care team

Before radiation simulation, you will meet the radiation therapy care team. They will talk with you about what to expect during radiation therapy.

A child life specialist may meet with your child to help them prepare. They can:

• Show your child the imaging equipment
• Explain the process in a way that fits their age
• Talk with them about what to expect
• Create a plan for coping  

Help your child understand

Children and teens may have questions, worries, or ideas about radiation that are wrong. Clear, age-appropriate information can help your child:

• Be less afraid
• Trust you and the care team
• Feel more in control
• Learn coping skills

Use the word “radiation” so your child will be familiar with it. Explain it in a way that is easy for them to understand.

• Toddler: Use words like “boo-boo,” “owie,” and “medicine.” Explain that the medicine goes to the “boo-boo” to help them feel better.
• Preschooler: Explain what will happen in simple terms. “A big machine will send a special kind of light to the part of the body that is sick. The machine doesn’t touch you, and it won’t hurt.”
• Early school-age: Explain that radiation is a type of treatment they cannot see, feel, or touch. A machine sends a special kind of invisible energy to the sick parts of the body. Your child’s job is to stay still so the radiation only goes to the parts that need it.
• School-age: Explain that radiation stops sick cells from growing or spreading. A machine sends invisible energy to the sick cells. They will not see, hear, or feel the radiation. Their job is to stay still so that the radiation only goes to where it is needed.
• Teens: Teens may want more detailed information. They may ask to talk with the doctor.

Give reasons for the simulation and treatments. Let your child know that they did not do or say anything to cause the disease or treatment.

Help your child plan things to do during the session and while they are waiting. Offer choices when you can, such as listening to music or watching a movie.

During radiation simulation

Your child should wear loose, comfortable clothing to their appointment. T-shirts and sweatpants, pajama bottoms, or other elastic waist pants are best. Try to avoid clothing with metal snaps, zippers, or buttons. These can interfere with imaging.

Your child may need to take some clothing off for the simulation. This helps the care team perform scans and place marks on your child’s skin. Staff will give your child a hospital gown to wear.

A parent or caregiver can go with your child to the simulation area. Once the session begins, the caregiver will return to the waiting area.

Imaging tests

Your child will have imaging tests to make sure their body is in the best position for treatment. This may include a CT scan and an MRI.

Contrast material may be given through a vein by IV for imaging tests. This makes the images from scans more clear.

Marking the skin

When your child is in the correct position, the therapist will make small marks or tattoos on your child’s skin. These marks help the care team aim the radiation to the same place each session.

• Radiation tattoos: In most cases, these are freckle-sized tattoos made with a sterilized needle. Your child may feel a tiny pinch or sting when the mark is made. These marks are permanent. They do not interfere with any other treatment your child may get.
• Permanent marker or paint pen: Marks made with a permanent marker or paint pen stay until radiation therapy is complete. If your child has a mask, marks will be made on the mask and not the skin. The therapist may reapply the marks at each new session to make sure they are easy to see.

Helping your child stay still during radiation simulation

A device may be made to help your child stay still during treatment. If a device is made, it will be used for each treatment.

Mask

The therapist may use a mask to hold your child’s head in the correct position. This mask is made from a flat piece of plastic that has small holes in it. It is made just for your child.

To make the mask, the therapist will:

1. Help your child get into the correct position.
2. Place a flat, plastic sheet in a dry heat oven to make it soft.
3. Take the plastic out of the oven for a few seconds so it can cool.
4. Place the plastic on your child’s face and stretch it down over the chin.

As it cools, the plastic hardens. Your child will be able to breathe easily through holes in the mask.

If your child’s treatment requires a mask, their hair should be in the same style for each simulation and treatment. Sometimes, the care team may ask that your child get a haircut before their session. This helps make sure the mask holds your child’s head in the correct position.

Headrest

The therapist may make a mold that supports your child’s head while they are lying on their back. To make this mold, the therapist will:

1. Help your child get into the correct position.
2. Place a flat, plastic sheet in a dry heat oven to make it soft.
3. Take the plastic out of the oven for a few seconds so it can cool.
4. Place the plastic under your child’s head.

As it cools, the plastic hardens. The mold forms into the shape of the back of your child’s head 

If your child will be on their stomach during treatment, a similar facemask will be made. The therapist will place an oxygen tube between the table and the mask so your child can breathe easily.

Vac lock bag

A vac lock bag is a type of body mold that helps hold your child’s body in the correct position. It can support the head, abdomen, leg, or another part of the body. Your child will lie on the bag. A vacuum will remove the air from the bag, causing the bag to mold around your child’s body.

Alpha cradle

An alpha cradle is used for Total Body Irradiation (TBI). To create an alpha cradle:

1. Your child will lie on the TBI table, on top of a vac lock bag. 
2. The therapist will pour a foaming solution inside a plastic bag (the alpha cradle). 
3. The therapist will place the bag on top of your child like a blanket. 
4. The bag will harden and form the shape of your child’s body.

General anesthesia

Your child may need general anesthesia to help them stay still during the radiation treatment. Your medical team will discuss this with you. In some cases, your care team may recommend that your child try the simulation without anesthesia. 

If your child gets anesthesia, you or another caregiver may stay with them until they fall asleep. The anesthesia team monitors your child the whole time. They will call you to the recovery room when your child wakes up.

Your care team will let you know your schedule for simulation and radiation treatments. Your child may also have an appointment with a child life specialist. If you have questions about simulation or radiation therapy, talk to your care team.  

Questions to ask your care team

• How long will the radiation simulation take?
• Can I stay with my child during the appointment?
• What clothes should my child wear for the simulation?
• Will my child need anesthesia or sedation?
• Will my child need contrast?
• How should my child prepare for the simulation appointment?
• Will my child get tattoos, or will they get marks with a marker or pen?
• If tattoos are used, how many marks will there be?
• What types of positioning devices will be used?
• What will happen if my child cannot stay still?
• What can my child bring to help them feel comfortable?
• How do you keep children calm if they are scared?

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