Stereotactic body radiation therapy (SBRT)
This is a specialized type of external beam radiation that allows highly precise delivery of high doses of radiation to small targets. Typically treatment with this technique is completed in 3-5 treatments over the course of 1-2 weeks. This is opposed to the daily standard external beam radiation treatment that is typically given over the course of multiple weeks.
This technique is currently being used in situations where treatment options have previously been limited. It is currently most commonly being used in cases where patients have a limited number of recurrent sites to deliver an ablative dose of radiation. Examples include limited disease in recurrent lymph nodes, the lungs, the spine, and the liver.
The first image shows the recurrent lymph node outlined in red.
The second row shows images (axial, coronal, and sagittal) of the distribution of the radiation dose that was delivered to this area. One can see that the dose of radiation to this target is very tightly distributed to avoid as much normal tissue as possible.
External Beam Simulation and Treatment process
Do I need to do anything to prepare for the simulation?
We ask that you come to the simulation with a comfortably full bladder. Otherwise no additional preparations are needed.
What happens during simulation?
The purpose of the simulation is to perform a CT scan of the area that we are going to treat in a position that can be reproduced daily. The most typical treatment position is having the patient laying down flat on their back with their arms up on their chest.
The CT scan from this simulation is sent to our dosimetrists and physicists and is used to plan how your radiation will be delivered based on your specific anatomy. The position that you are simulated in is very important because all of the radiation treatment planning is based on this position. Since the room that you are simulated in is different from the room where your radiation treatments occur we need to make sure that we can set you up the same way in both rooms. So in essence we are “simulating” what’s going to happen for your actual radiation treatments.
At the end of the simulation you will get roughly 3 small permanent tattoos about the size of a dot. These marks allow the therapists to make sure you are aligned appropriately when you come back for your treatment.
The entire simulation process takes about 1 hour.
We will start working on your plan and patients typically start treatment within 1 week from the time of their simulation.
Prior to each treatment you should have a comfortably full bladder and to the best of your ability try to stay regular with your bowel movements so that you don’t get constipated or have too much gas.
For the actual external beam radiation treatments you will be brought to the treatment room that has a linear accelerator. This is the machine that actual generates and delivers the radiation. You will be put onto the radiation treatment table in the exact same position that you were in for your simulation. Radiation therapists are involved in helping to get you set up on the table. After you are set up the therapist will step out of the room. There is a camera and microphone in the room should you need to communicate with the therapist. In all cases weekly imaging will be performed to make sure that you are setting up properly and these films are reviewed by your physician. In some cases daily imaging may be performed prior to your treatment. These films give us information about your set up but don’t give us information about whether you are or are not responding to treatment.
After your position has been verified the treatment will begin. You will see and hear the linear accelerator moving around you. You will be laying still. You will not see anything coming out of the machine or feel anything while you are being treated. The treatment takes about 5-10 minutes to complete. After the treatment is done you will be helped off of the table and you will be ready to leave the clinic. For your daily treatments you will not typically see your physician as the treatment set-up and delivery of the radiation is done by the therapists who are specially trained to do this.
For external beam you will see your doctor at least one time per week to discuss how you are doing on treatment. If you need to see him/her more often than you can let one of the therapists or nurses know and they can help coordinate this.
The most common chemotherapy agent given at the same time with radiation for gynecologic malignancies is cisplatin. This medication is given intravenously once per week by a medical oncologist. On the day that you get chemotherapy you should get your chemotherapy first and then come in for your radiation treatment afterwards.
Brachytherapy is a vital component of treatment for women with gynecologic cancers both in the upfront setting as well as potentially in the recurrent setting. Brachytherapy is a highly skilled technique and our team has some of the most extensive experience of any group in the United States.