Radiation therapy: the use of high energy x-rays or particles in an attempt to damage cancer cells.
Jake - incompletely resected soft tissue sarcoma
A Radiation Therapy Technician marks our patient for treatment.
Tools such as clothes pins are used to "spare" skin that we do not want in the treatment field.
Gauze is used as "bolus" to protect certain structures and/or reduce or increase the amount of radiation received at certain levels (i.e. skin).
Final set-up means we are ready to treat.
Radiation therapy can kill cells in two ways: occasionally, the beam will kill cells outright.
More often, each treatment does a small amount of damage to the cells, which then die when enough damage has been accumulated. Often, cells do not die until they attempt to reproduce, and sometimes the cells do not die but permanently or temporarily lose their ability to reproduce.
In most cases, the goal of radiation therapy is to reduce the size of a tumor or prevent a tumor from coming back after it has been removed surgically. In some individuals, the goal of treatment is to stabilize the tumor at its current size. Radiation therapy may also be utilized in an attempt to relieve pain and/or decrease symptoms.
Treatment planning is assisted by radiographic images and a treatment planning computer; sometimes a CT or MRI will be necessary for planning. The exact treatment plan is determined by Dr. Meleo, a board-certified veterinary radiation oncologist, with the help of a dosimetrist, when necessary. Blocks may be utilized to protect normal structures within the treatment field; in some cases, these blocks will be customized. Multiple miscellaneous supplies are utilized in an attempt to recreate positioning for each treatment.
Radiation therapy does involve general anesthesia at each treatment; a veterinarian and a veterinary technician or assistant are always present. Closed circuit TV allows us to monitor respiration. We also have a pulse oximeter that displays the patient's pulse and oxygen saturation values during treatment.
Most animals that undergo radiation therapy will experience some side effects. The type and severity of these effects varies greatly depending on the location of the tumor, the number of treatments given and the total radiation dose that is delivered. Nausea and vomiting after radiation therapy is rarely seen in dogs and cats unless a large amount of the abdomen is irradiated.
"Mr. Kat" receiving strontium-90
Strontium-90 and Intensity Modulated Radiation Therapy are two treatment options we also have available for our patients. Strontium-90 is delivered via a probe to superficial tumors, thus sparing deeper tissues, while IMRT techniques allow us to more directly treat a tumor volume while sparing normal tissue surrounding the tumor. If either of these options is appropriate for your pet, it will be discussed in detail with you.
"Sammy" 3 weeks post strontium-90 treatment for squamous cell carcinoma of the nose