Fighting cancer is challenging. To help you prepare for the fight, here is a brief outline of what you can expect when you visit your radiation oncologist and begin brachytherapy treatments. The details of some of the steps may differ, depending on your particular case and what type of brachytherapy you receive.
A clinical examination is first performed to understand the type and extent of the cancer and your unique treatment needs. This will include investigating the size and position of the tumor and its relation to surrounding tissues and organs. A range of imaging equipment, such as x-ray, ultrasound, computed tomography (CT scan), positron emission tomography (PET scan), and magnetic resonance imaging (MRI), are used to create a detailed picture of the tumor.
Treatment Process & Delivery: HDR Brachytherapy
HDR brachytherapy involves placing a single high-strength radioactive source next to or inside the tumor for a short period of time, usually a few minutes, and then removing it. Your radiation oncologist uses catheters or needles — usually called "applicators" - to direct the radioactive source to the tumor. The applicators are typically placed under anesthesia (local, conscious sedation, spinal or general), depending on the area being treated. After applicators have been inserted, images will be taken in order to optimize the treatment plan and calculate the required source positions and treatment times.
Your clinical team may refine the position of the applicators and the treatment plan before actual treatment begins. This ability to modify the dose after the applicators are placed is an important advantage of HDR brachytherapy; because the computer can control how long this single radiation source remains in each of the catheters, the radiation oncologist is able to control the radiation dose. The tumor can receive a higher dose, while the neighboring tissues receive a lower dose.
After the treatment plan has been finalized, the radiation is delivered to the tumor by a technique known as "afterloading." The applicators are connected to an "afterloader" machine, which contains the radioactive source. Once the afterloader is connected, the clinical team will leave the room to start the treatment from a control area just outside the door. The source will then be automatically extended from the afterloader, via the applicators, to the treatment site. Depending on the treatment site and the dose being delivered, the treatment will last for a number of minutes. After the treatment is completed, the source of radiation is safely returned to the afterloader and there is no radiation left inside the body. Most patients are not required to stay in the hospital and may return home the same day.
Treatment Process & Delivery: LDR Brachytherapy
LDR brachytherapy involves placing permanent seed implants near the tumor. This technique is most commonly used to treat prostate cancer, and is usually performed under general anesthesia. The treatment team uses an ultrasound to guide the needles into place; then tiny radioactive seeds are injected into the prostate. The seeds give off their radiation at a low dose rate over several weeks or months, depending on the type of seeds used, and then the seeds remain in the prostate gland permanently.
After the seeds have been placed into the prostate gland, you will be slightly radioactive. The radiation oncologist will provide outpatient instructions for how to best avoid exposing family members and others to the radiation. Over the course of 2-6 months, the radiation will "wear out," and you will no longer be radioactive.
Some gynecological cancers may be treated with a type of LDR that involves placing radioactive sources within the cervix and uterus, and the patient stays in the hospital immobilized for up to 30 to 40 hours. Then the sources are removed, and the patient may return home. This technique is not often used, but may be appropriate for some cases.
Whether you are treated with HDR brachytherapy or LDR brachytherapy, your doctor will monitor your progress over the course of several follow-up appointments. The number of follow up sessions will be determined based on your particular treatment needs. Follow-up appointments are a great time to ask your doctor any questions about how you may be feeling.