Radiation Therapy (Radiotherapy) Procedure for Dogs

Radiation therapy, or radiotherapy, is a treatment procedure that uses ionizing radiation to kill cells – often as a part of cancer treatment for dogs. Radiotherapy involves delivering beams of photons, electrons, or waves to damage the cell’s DNA.

There are several types of radiation therapy. Some is delivered by injection of radioactive particles. This is commonly used to treat hyperthyroidism in cats. Another type is called “Brachytherapy” in which radiation is delivered through a radioactive implant. The last time of radiation therapy involves beaming x-rays on a particular area.

Radiation therapy can refer to the used alone as a treatment procedure, before or after surgery, or with or without chemotherapy. The recommendation for radiation therapy depends on the type of tumor and location of the tumor. Radiation therapy is not a treatment option for all types of cancer.

Many times the tumor cannot be destroyed but its size can be minimizing allowing for surgery or reducing the dog’s symptoms of pain or bleeding.

Each type of cancer is studied to determine the most effective treatment combination (surgery, chemotherapy and/or radiation therapy). Based on this research, radiation therapy recommendations for your dog’s particular situation will be given by your veterinarian.

The goal of radiation therapy is to kill tumor cells while minimizing damage to adjacent tissue. Another goal is to give a radiation therapy dose that will minimize side effects therefore allowing your dog to maintain a good quality of life while maximizing the radiations effect on the cancer cells.

How Is Radiation Therapy Done?

Radiation beam therapy is done by focusing an x-ray beam on or toward the affected area. Markers or tattoos are sometimes used to ensure that the appropriate area is consistently being treated.

It is often administered weekly for 2 to 5 weeks or more. Again, this depends on the particular type of tumor, tumor location and your dog’s particular situation.

Is Radiation Therapy Painful to Dogs?

Radiation therapy is painless and in low doses causes very few side effects. The most common side effects involve the tissue area being treated. Swelling, skin damage, and/or hair loss can occur. In addition, some pets may seem tired or be less active during radiation therapy.

Because pets don’t stay still, most radiation therapy procedures are done while a pet is sedated. Any pain involved is associated with the placement of the IV catheter or needle stick to give the sedation. As with people, the pain experienced from a needle will vary from individual to individual.

Is Sedation or Anesthesia Needed?

Yes, sedation or anesthesia is needed in most patients to keep them still during the treatment procedure. The initial treatment time and anesthetic time is longer while the machine is set up to focus on the tumor. Subsequent treatments require a short anesthetic or sedation time – often only 10 to 20 minutes.