Superficial Radiation or Brachytherapy?
Last updated: November 2022
I recently took a phone call at work from a man with questions about radiation treatments. His dermatologist had referred him to treat a skin cancer behind his ear with brachytherapy. He had done it before but had also heard about superficial radiation therapy (SRT). The man had a few excellent questions:
- What is the difference between brachytherapy and SRT?
- Do the treatments take the same amount of time?
- Is one way better than the other?
What is brachytherapy?
Brachy is a Greek prefix meaning “short.” Brachytherapy is a short-distance therapy in this context. Brachytherapy is a style of radiation therapy that puts a radioactive source on or near the area that needs treatment. Sometimes, this can involve implanting little radioactive pieces inside the body. These are called “seeds.”
For skin cancers, brachytherapy is usually performed with a machine that places the radioactive source near the skin's surface. It stays there for a certain amount of time to deliver the prescribed dose. The radioactive source is stored in a vault inside a brachytherapy machine.
First, the device is calibrated to determine the exact amount of radioactivity given off by the source at that time. Then, the machine is positioned over the skin cancer. When the treatment begins, the radioactive source leaves the vault and exposes the cancer to its radiation dose.
What is superficial radiation therapy (SRT)?
Superficial means at the surface. SRT treats skin cancers at or near the surface of the skin. It does not penetrate deep into the body. SRT is non-invasive and does not involve the use of radioactive materials.
Superficial radiation uses photons or electrons created electronically. There is no physical radioactive source inside the machine. The machine is computer operated, and the exact dose and energy of the treatment are set at the time of treatment. There is only radiation while the treatment is performed. Both before and after, the machine emits no radioactivity.
Treatment times are different for both styles of radiation
Brachytherapy requires a calibration of the machine when the patient arrives. It only takes a couple of minutes. But this does not have to be done with a superficial machine.
The treatment lengths also vary with brachytherapy depending on the source's intensity. They typically range from 1 to 5 minutes. Throughout a course of brachytherapy treatments, the treatment time may become longer if the source is decaying. Or they may become quicker if a new source is installed in the machine.
Superficial treatments are always the same length of time. Each treatment is a fraction of the overall dose prescribed by the doctor. The treatment times, specifically with the SRT-100 by Sensus Healthcare that I operate, are around 30 seconds. Each patient has an individual plan. But even the largest lesions do not exceed 90 seconds per treatment.
Both are effective treatments
I have worked with both brachytherapy and superficial radiation. Each treatment has been proven to destroy cancerous cells and get rid of non-melanoma skin cancers. They both can serve the same purpose and do so successfully. But in my experience giving these treatments, treatment times and convenience were better with the superficial radiation unit.
Remember that everyone’s skin cancers are different. Always talk to your doctor about your treatment options. Please keep in mind these machines are costly for your dermatology office to own and operate. Upgrading and replacing these machines is often unnecessary because they are maintained and well taken care of. Getting the newest device is not always necessary when your current investment is still working perfectly.
Do you sunscreen in the fall?