Targeting Arthritis Pain: Understanding Low-Dose Radiation Therapy

May is Arthritis Awareness month in the United States, but February is the shortest month of the year and arthritis often gets short-shrift because it is so common. Therefore, February is the perfect month to talk about arthritis.

What Exactly Do We Mean by Arthritis? 

According to the Arthritis Foundation, arthritis is the #1 cause of disability in the United States affecting 60 million women, men and children. There are more than 100 different types of diagnosed arthritis. The basic tenet of arthritis is that it is chronic inflammation in one or more joints that cause debilitating pain leading to problems with movement. 

What Causes Arthritis?

We do not actually know what “causes” arthritis in each person, but we know what happens to the arthritic joint. We know that chronic painful joints often develop later in life as the body has excessive wear. This leads to degenerative damage of cartilage with increased pain and swelling. Often there can be radiographic changes found in the joints. Arthritis can be related to certain genetic factors, excessive use or prior injury, autoimmune conditions, and even diet and medications can affect our joints. 

How is Arthritis Diagnosed?

Arthritis is often diagnosed by a medical provider. The leading symptom is chronic joint pain. A clinical exam may show symptoms such as joint swelling, redness, nodules, or malalignment in the joint. A clinical diagnosis is usually made based after a thorough medical history and exam. Often the next step is radiographic imaging such as X-ray, Ultrasound or MRI to rule out more severe conditions. 

How is Arthritis Treated?

After a diagnosis of arthritis is made, the patient is often referred to a specialist. This could be a physical therapist, an orthopedic surgeon, a rheumatologist, a pain specialist or other medical provider. There are a multitude of treatment options from over-the-counter medications to complex surgical procedures with a wide variety of treatment options in between. 

What is Low-dose Radiation Therapy for Arthritis?

Low-dose external beam radiation therapy for arthritis is just one non-invasive treatment option available for patients suffering with chronic joint pains. This is done in a specialized radiation therapy treatment center using a very complex linear accelerator (Linac) machine. 

Who is Low-dose Radiation Therapy for Arthritis Designed for?

Patients are selected for this treatment based on specific qualifying criteria, which are based on previous clinical trials showing effectiveness:

• Age 50 or older
• Diagnosed arthritis by a medical provider with radiographic evidence of degenerative joint disease
• One or more joints (i.e. feet/ankle, knee, hip, sacroiliac joint, shoulder, elbow, hand) but NOT including head/neck or spine
• Patients NOT immediately interested or able to have joint surgery

Qualified patients will then receive six treatments of low-dose radiation (50 cGy) spaced out over three weeks (two 15-20 minute sessions per week for three weeks) targeting just the arthritic joint.

How Does Low-dose Radiation Therapy Work to Control Pain?

Low-dose radiation therapy works in a joint by changing certain inflammatory mediated cells. Lymphocytes (white blood cell type) are eliminated quickly with the low-dose photon beams. Neutrophils (white blood cell type) are also damaged and no longer able to release cytokines, which are chemicals released into the blood stream to recruit more white blood cells to the inflamed joint. Lastly, the endothelial lining of the tiny blood vessels of the radiated joint are changed because the radiation energy transforms the cells making them less porous. This limits the ability for new inflammatory cells to enter the joint space. Less inflammation in the joint reduces chronic pain.

What Happens to the Joint that has been Exposed to Radiation?

Low-dose radiation therapy is considered a therapeutic dose for inflammatory mediators in the joint but not a strong enough dose to effectively damage the other tissues. Therefore, the skin is not damaged and will not redden, dry or scar. Likewise, the bone, cartilage and soft tissues (i.e., muscles, ligaments and tendons) are not effectively damaged. The joint can still be treated with the other treatment options such as physical therapy, steroid or other injections and ultimately surgical options as indicated.

How Long Does the Effect Last?

Based on research data, the positive effects of joint relief from low-dose radiation therapy can last up to three years. The treatment can also be repeated after waiting three months after initial treatment.