Pacemaker, Metal Implants, or a Joint Replacement: Can I Still Get LDRT?

Three of the most common questions programs hear: I have a pacemaker. I have screws and plates in my knee. I already had the joint replaced. Does any of that rule out LDRT? The short answer: a pacemaker usually does not, metal hardware usually does not, and a joint that has already been replaced usually does. Here is why, and what the program will check in your case.

If You Have a Pacemaker or ICD

Radiation can interfere with the electronics in a pacemaker or defibrillator. The 1994 AAPM guideline (Task Group 34) found that pacemakers can fail at doses as low as 10 Gy and show functional changes at doses as low as 2 Gy, so it recommended keeping the accumulated dose to the device at 2 Gy or less^[1]. That guideline has since been replaced by AAPM Task Group 203 (2019), which uses a three-level risk system based on the expected dose to the device, whether you depend on it, and the beam energy used^[2].

For LDRT of a knee, the math is reassuring. The total treatment is 3 Gy to the knee^[3]. A chest device is far from the knee field, well past the 10 cm cutoff that the AAPM's own checklist uses: if the treatment field edge is more than 10 cm from the device, no further action is needed^[2]. The scatter reaching the device is far below the 2 Gy concern level.

Even so, the team does not ignore it. The AAPM checklist asks for a device alert in your chart, a copy of your device card, and a cardiology or electrophysiology appointment when needed, so the device is checked before and after treatment^[2]. Tell the program about your device at the first call, and bring your device card to the visit.

One caveat: these pacemaker guidelines come from cancer radiotherapy, where doses are much higher. No published LDRT study measured the exact scatter dose to a chest device during knee treatment. The team applies the same standard precautions anyway.

If You Have Metal Hardware in the Joint

Screws, plates, or pins near the joint do not usually disqualify you. Metal affects how radiation is planned: it creates artifacts on the planning CT scan and changes how the dose spreads. The AAPM's Task Group 63 is the physicist's standard for this, and its core advice is to choose beam angles that avoid shining straight through the metal^[4].

Practically, this means the planning team needs to know about every piece of hardware in the area. Bring your operative notes or implant records if you have them. No published LDRT study or guideline says metal hardware rules out treatment. It is handled in the planning, not as an exclusion.

If the Joint Has Already Been Replaced

This is the real exclusion. Cleveland Clinic's LDRT care path lists joint replacement among its exclusion criteria, alongside rheumatoid arthritis, vascular disease, prior joint trauma, and lymphedema^[3]. The reasoning is straightforward: LDRT targets the arthritic joint lining and surrounding inflammation, not metal and plastic. As Dr. Byoung Hyuck Kim noted at ASTRO 2025, LDRT will not regenerate tissue in a destroyed joint^[5]. The German DEGRO guideline advises considering radiotherapy after other measures are exhausted but before joint replacement^[3].

Wanting LDRT on a different joint is fine. If your right knee was replaced, your left knee, hands, or shoulders can still be treated. Cleveland Clinic's care path covers knees, hips, hands, shoulders, ankles, and elbows, and treats up to three sites at a time^[3].

What the Program Will Check at Your Visit

• Your imaging: the program reviews recent X-rays or MRI to confirm the arthritis stage. Cleveland Clinic's care path treats joints with symptoms lasting more than three months^[3].
• Your device card: if you have a pacemaker or ICD, bring the model and the card so the team can estimate the dose to the device and involve cardiology^[2].
• Your hardware list: every screw, plate, or prior surgery in the area, so the planners can avoid beaming through metal^[4].
• Your age: the German DEGRO guideline advises treating patients over 40; Cleveland Clinic chose to be more conservative and starts at 65. Pregnancy is excluded in the trials^[3][6].

The short version: pacemaker, usually fine, the team documents it and checks the device. Metal hardware, usually fine, the planners work around it. Replaced joint, not a candidate for LDRT of that joint. Other joints, still eligible. When in doubt, call the program with your device card and your surgery history. They will tell you in one visit.

References:
1. Marbach JR, et al. Management of radiation oncology patients with implanted cardiac pacemakers: report of AAPM Task Group No. 34. Medical Physics. 1994;21:85-90 (AAPM Report 45). AAPM
2. Miften M, et al. Management of radiotherapy patients with implanted cardiac pacemakers and defibrillators: A Report of the AAPM TG-203. Medical Physics. 2019;46(12):e757-e788. AAPM
3. Low-Dose Radiation Therapy Reemerging for Osteoarthritis. Cleveland Clinic ConsultQD (Chirag Shah, MD). ConsultQD
4. Reft C, et al. Dosimetric considerations for patients with HIP prostheses undergoing pelvic irradiation: Report of the AAPM Radiation Therapy Committee Task Group 63. Medical Physics. 2003;30:1162-1182. AAPM
5. Low-dose radiation therapy offers substantial relief to people with painful knee osteoarthritis. MedicalXpress, September 2025 (reporting Kim BH, et al., ASTRO 2025). MedicalXpress
6. Rogers S, et al. Prospective evaluation of changes in pain levels, quality of life and functionality after low-dose radiotherapy for epicondylitis, plantar fasciitis, and finger osteoarthritis. Frontiers in Medicine. 2020;7:195. Frontiers