Fractionated Stereotactic Radiotherapy -A Guide For Patients with Arterio-Venous Malformations (AVM)
Fractionated Stereotactic Radiotherapy is a precise way to aim beams of radiation, from many angles, to cover a tumor. The treatment is split into a number of smaller doses (fractions) of radiation. By doing this, the effects on the normal, healthy tissues are reduced while the tumor receives the desired treatment.
Types of tumors are treated with Fractionated Stereotactic Radiotherapy
- brain tumors, both benign and malignant
- metastatic brain lesions
- non-tumor lesions in the brain such as Arterio-Venous Malformations (AVM)
- vestibular schwannomas or acoustic neuromas
- meningiomas
Before your treatment
Before treatment can begin, you will need a bite tray, head mold and face mask. The bite tray is used to help us place you in the same position for every treatment. The head mold and face mask are used to keep your head from moving. We will need to look at your teeth before the bite tray is made to make sure that you do not have loose teeth, fillings or caps. A loose tooth, filling or cap could be pulled out when taking the bite tray out of your mouth. If you know that you have loose teeth, please see your dentist before being fitted for a bite tray.
Step 1
Stealth, MRI and MRA
As part of the planning process, a stealth MRI and MRA scan may be needed. This scan is like those you may have had in the past, but is used as part of the treatment planning. The images are closer together than other MRI scans. This gives us a more defined picture of the treatment area.
The stealth MRI must be done at the UW Hospitals and Clinics because the scan needs to be fed into our computer in order to plan your treatment. At this time, we cannot retrieve scans done at other places. If you have never had an MRI before, please let the nurse know, so you can be given a handout that explains it in detail.
If you are claustrophobic (feel afraid in confined spaces) or have problems completing MRIs, please let your doctor or nurse know so that medicine can be ordered to help you relax. Please let the doctor or nurse know if you have any of the items listed below.
- pacemaker
- artificial heart valve
- defibrillator
- brain aneurysm clips
- implanted pumps or chemotherapy ports
- neurostimulators
- eye or ear implants
- stents, coils or filters
- kidney disease
StealthCT(CAT) Scan
As part of the planning process your doctor may order a special CT scan called a Stealth CT. This CT is very similar to other CT scans you have had in the past, however the images are closer together than other CT scans. This gives us greater detail on your AVMand will be used for planning. Your doctor will decide if you need both the MRI/MRA and a CT scan.
If you have never had a CT scan before please let your nurse know so you can be given a handout that explains it. The scan is the final step before we can begin planning your treatment. If IV contrast is needed a blood test called a creatinine level may be done, prior to the CT, to make sure that your kidneys are working well. Your local doctor can do the test or it can be done here.
If you have an allergy to the CT contrast or are allergic to shellfish or iodine products please let your doctor or nurse know.
If you have diabetes and take oral medicines (specifically, GlucovanceÒ, metformin, MetaglipÒ, AvandametÒor GlucophageÒ) or insulin to control your diabetes, please let your nurse or doctor know. You should NOTtake this the day of your scan and for 48 hours after the injection of contrast. We may need to find a short-term plan to manage your blood sugars until you can resume this medication. This may involve talking to your primary doctor.
Remember: You should have nothing to eat or drink for four (4) hours before the CT scan, but once the CT and MRIare completed, we ask you drink extra fluids that day to flush the dye out of your system
The Bite Tray
On the day of your first visit with the doctor or on the day of your MRI, a custom bite tray will be made. The bite tray takes about 20 minutes to make. You will sit upright. You will be given a white plastic mold and asked to insert it into your mouth a few times. This helps you practice taking the tray in and out of your mouth and checks for proper fit and size. Once the right size has been chosen, you will insert the tray again. This time it will contain a mint-flavored molding material. You will bite down on the tray with moderate force, about as hard as you would bite into a piece of fruit. You need to hold the bite for 4-5 minutes. Do not chew or try to talk while the mold is being made.
After the tray has hardened you will remove it. It will be hard to remove. The bite tray will be checked to be sure that we have a proper mold. You will insert and remove it until you become comfortable with the fit. We check the fit. If there is a good fit, you are fininshed. If the fit isn't right, we will need to start over until we hav the proper fit.
Step 2
The frame placement and the CT scan
On this day, you will be asked to arrive at the hospital very early in the morning. You can expect to be there for about 9 hours. Because you will be given medicine to help you relax, you should not drive or make important decisions until the next day. You must make plans to have someone drive you home.
The night before the procedure do not eat or drink anything after midnight, except you may take your medications with a small amount of water.
If you have diabetes and take oral medicines (specifically, Glucovance®, metformin, Metaglip®, Avandamet® or Glucophage®) or insulin to control your diabetes, please let your nurse or doctor know. You should NOT take this the day of your scan and for 48 hours after the injection of contrast. We may need to find a short-term plan to manage your blood sugars until you can resume this medicine. This may involve talking to your primary doctor.
Once you arrive at the hospital you will change into a gown. An IV line will be placed in your hand or arm. You will get a pill to help you relax.
You will be moved to the Radiotherapy Department where a frame is applied to your head by a neurosurgeon. The frame can cause some pain and discomfort. A local anesthetic will be used to numb four sites of your scalp (two on the forehead and two in the back of your head) before the fram placement. This part of the procedure takes about 10 - 15 minutes. You will be given medicine to help you relax while the frame is put on.
After the frame is placed, a CT scan is done. This scan is used for planning your treatment. If you have never had a CT scan before please let your nurse know so you can be given a handout that explains it in greater detail. You will have your bite tray in place for the CT. Before the CT scan you will be given an IV contrast agent. The contrast agent will allow us to see your brain better. Some people feel a warm flush or have a metal or strange taste in their mouth with the contrast. This is normal and will go away after the contrast is finished.
Before the CT scan is done a blood test called a creatinine level will be done to make sure that your kidneys are working well. If you have an allergy to the contrast agent or shellfish or have ever had a reaction to CT dye, please tell your doctor or nurse.
After the CT is finished, you will wait in a comfortable area while the treatment plan is finished. We will provide you with breakfast and maybe lunch. About mid-afternoon, after the planning is done, you will be brought into the treatment room. You will lie on the treatment table with the frame locked into a special holder. You will be asked to insert the bite tray a few times to make sure it is in the right place. While you are on the table we will confirm the treatment plan. After the plan has been confirmed, we will give you the first dose of radiation. This means we will step out of the room and the machine will rotate around your head as the radiation is given.
After the treatment is completed, the frame will be removed. We will clean the pin site areas and apply an antibiotic ointment. You will be sent home shortly after with written directions .
You may have some short-term swelling around both eyes. This is caused by the local anesthetic placed at the pin sites. This begins about 2-3 days after the treatment. It may last from days to weeks. This is normal and should go away by itself. You can apply cool clothes to your eyes several times a day for about 20 minutes at a time for the first few days. This may help reduce the swelling.
You may have some pain, tenderness or numbness around the pin site area for up to a few weeks. This is normal and should go away by itself.
You may feel a little tired for a day or two. Resume your normal activity as you can.
Keep the pin sites clean. You will be given antibiotic ointment. Put it on the pin sites for the first 2-3 days. You will not be able to wash your hair for 3 days after the treatment
While at home, call the doctor if you notice any of the following:
- Increasing or severe headaches that are not relieved by TylenolÒ
- Headaches that occur daily or several times a day, even if relieved by TylenolÒ
- Headaches associated with nausea and vomiting
- Nausea or vomiting
- Any change in strength or sensation (numbness or tingling)
- Being clumsy or problems with the movement of a hand or leg
- Vision, hearing or speech changes or difficulties
- Balance or walking difficulties or dizziness
- New onset of confusion
- New seizures or worsening of seizures
Step 3
About one week after the frame placement you will return to the Radiotherapy Department to have your face mask and head mold made. This will take about one hour. You will have the bite try in during the making of the face mask and head mold. After these steps you will be ready to continue your treatment.
Head Mold
The head mold takes about 5-10 minutes to make. You lie on a table in a comfortable position. We place a foam-filled cloth under your head. The mold will be cool and wet when it is placed under your head and slowly warms and dries as it hardens. The foam mold has a strong odor that will go away as the mold hardens. As you are lying on the table we sculpt the mold around your head. Please keep your head still during this time. Please do not wear turtlenecks or high-necked sweaters on this day. They will get in the way of the molding process. If you have long hair, please wear it down or in a low ponytail. If you wear any hair clips or barrettes, they must be removed before the head mold and face mask are made.
The Face Mask
The face mask takes about 15-20 minutes to make. You lie back on the table with the head mold in place. A mesh film is placed across the top of your head, forehead, and nose, ending at your top lip. The mesh is flexible plastic that is placed in warm water. As it molds to your face, it becomes stiff. The face mask will be molded to fit the contours of your eyes and your nose. It is important that the mask fit snugly around these features. The mask takes about 10-15 minutes to harden around your face. As it hardens you will feel the mask tighten slightly. It will not hurt, but you will notice it. We need to lightly press on your eyes and mold the mask to the bridge of your nose. If you are claustrophobic or afraid of being in confined spaces, please let us know.
Treatment
After the head mold and face mask are made, you will be given the second dose of radiation. Patients with AVMs have one or two treatments per week for a total of six treatments. In most cases the first treatment is given the day of the frame placement. For others the first treatment will be the day the face mask and head mold are made. This first treatment takes about 60-90 minutes, due to the set up process. The rest of the treatments take about 30 minutes.
Your doctor will discuss with you the exact treatment needed for your type of lesion.
During Treatment
While you are having treatment you will see your doctor or nurse once a week to watch for the side effects of treatment. If you have questions at any time during your treatment, please let the therapist know and he or she will arrange for you to meet with a doctor. During the last week of treatment you will meet with your doctor to discuss follow-up care.
Side effects
Most of the time there are few immediate side effects. The most common side effects are listed below.
- Skin irritation – Red, dry skin, like a sunburn, may occur. While you are having treatments we will check your skin, give you a cream and talk with you about ways to protect and maintain your skin.
- Hair loss - hair loss is often only small patchy areas on the head. Hair loss generally starts about mid way thru treatment. The hair begins to grow about three months after the end of radiation.
- Fatigue - Many find that they are able to carry on their normal routines with little problem. Some find that they are tired the day of the radiation treatment and for 24-hours after treatment. Occassionally some people feel more tired near the end of treatments and may need to rest. Taking rest breaks is very important. You will need to listen to your body and rest as needed.
- Thrush - You should inspect your tongue and the inside of your mouth daily. It should be pink and smooth. If you notice any red or white patches on your tongue or develop a “funny or strange” taste in your mouth, please let your doctor or nurse know. Sometimes a yeast infection (thrush) occurs.
- Nausea and Nutritional Needs - Although rare, some patients may have nausea or vomiting during treatment. If you do, please let your doctor or nurse know, so medicines can be ordered for you. Nutrition is very important. Avoid alcohol and smoking. We do not want you to lose weight at this time. Try to eat three servings of protein and drink at least 6-8 glasses of water every day. Good eating and drinking habits will help lessen the other side effects. If you have further questions about nutritional needs please discuss them with your nurse. A dietician can help with any questions or concerns.
- Brain swelling - A small number of patients may have brain swelling during treatment or weeks to months after treatment is over. If this occurs, you will be treated with a steroid medicine to reduce the swelling.
Symptoms of brain swelling can vary depending upon the location and type of tumor or lesion you have. If you have any of these, tell your doctor. A few of the more common things to watch for are listed below.
- Increasing or severe headaches that are not relieved by TylenolÒ
- Headaches that occur daily or several times a day, even if relieved by TylenolÒ
- Headaches associated with nausea and vomiting
- Nausea or vomiting
- Any change in strength or sensation (numbness or tingling)
- Clumsiness or coordination difficulty of a hand or leg
- Vision, hearing or speech changes or difficulties
- Balance or walking difficulties or dizziness
- New onset of confusion
- New seizures or worsening of seizures
Risks
Your doctor will discuss the immediate and long-term risks of this treatment with you. The risks vary from patient to patient and depend on a number of factors.
Questions or concerns
While you are having treatments, you will see your doctor or nurse weekly. If you have any questions at any time during your treatments, please let the therapist working with you know and they will arrange for you to meet with a doctor.
If you have any questions or problems, please feel free to call the Radiotherapy Clinic at 608-263-8500. If the clinic is closed, your call will transfer to the hospital paging operator. Ask for the radiotherapy doctor on call. Leave your name and phone number with the area code. The doctor will call you back.
If you live outside of the area, call toll-free 1-800-323-8942.
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 12/10/2012
Copyright © 06/23/2011 University of Wisconsin Hospitals and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#5999
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