7 Myths About LDRT, Debunked

Many of the myths about low-dose radiation therapy for arthritis come from cancer treatment, some from nuclear medicine, and some from fear of the word radiation. Each section below takes one myth, gives the verdict first, and then the evidence. Where another page on this site covers a topic in more depth, we link to it.

Myth 1: I will be radioactive afterward

Verdict: false. LDRT is external beam treatment. A machine makes the beam, the beam exists only while the machine is running, and nothing radioactive is put into your body. Memorial Sloan Kettering states it directly: external beam therapy does not make a person radioactive in any way, and a person who has had it cannot contaminate or transfer radiation to anyone else^[1]. The International Atomic Energy Agency says the same in its patient guide: external beam radiotherapy does not make patients radioactive^[2].

So there is no need to keep your distance from family, sleep apart, or avoid holding a grandchild after a session. The treatments people picture here are different ones: radioactive iodine, which you swallow, or brachytherapy, where a radioactive source is placed inside the body for a time. LDRT is neither. Our FAQ gives the short answer to this question.

Myth 2: It is the same radiation as cancer treatment

Verdict: same kind of machine, very different dose. A course of LDRT for osteoarthritis is 3 to 6 Gy in total, given as 0.5 to 1 Gy at a time, 2 to 3 times a week, under the German DEGRO guideline^[3]. A course of radiation after surgery for a breast or head and neck cancer is typically 45 to 60 Gy^[4]. At cancer doses, the goal is to kill tumor cells. At 3 to 6 Gy, the goal is to calm inflammation in a joint.

Comparisons with X-rays or CT scans use a different unit. Imaging doses and background radiation are measured in millisieverts, a whole-body risk measure, while an LDRT dose is the absorbed dose in Gy to one joint. The two cannot be swapped. Our dose page works through the numbers and the units in full.

Myth 3: It will definitely cause cancer, or there is zero risk

Verdict: both versions are wrong. No dose of radiation is considered entirely risk-free, so zero risk is not accurate. But decades of use in Europe at these doses have not shown a clear rise in cancer, and the available studies are not large enough to rule out a very small risk. Our cancer risk page covers the doses, the follow-up data, and the estimates in detail.

Myth 4: It regrows cartilage and fixes the joint

Verdict: false. LDRT calms inflammation. It does not rebuild what arthritis has worn away. The University of Alabama at Birmingham program puts it in one sentence: the treatment reduces inflammation, and while it does not regrow cartilage, it can alleviate discomfort^[5].

The lead investigator of the Korean LoRD-KNeA trial made a similar point: where the joint is physically destroyed and cartilage is already gone, radiation will not regenerate tissue, but for mild to moderate disease it may delay the need for joint replacement^[6]. Results are judged on pain and function, not on X-rays.

Myth 5: It is experimental and unproven

Verdict: partly true. LDRT for arthritis is not new. A German national guideline on radiotherapy for painful degenerative skeletal disorders dates to 2015, recommending the 3 to 6 Gy range used today^[3]. German centers have used this treatment for decades, and the American Radium Society panel reviewed 52 studies for its 2026 appropriate use criteria^[7].

The controlled trial evidence, though, is mixed. A blinded, sham-controlled trial of hand osteoarthritis found no benefit^[8]. The ArthroRad trial, which compared a standard dose with a very low dose rather than with sham, found favorable pain relief in both arms after 12 months and no significant difference between them^[9]. And the Korean LoRD-KNeA knee trial found the 3 Gy group beat sham at 4 months, held the advantage at 8 months, and lost statistical significance by 12 months^[10]. LDRT is an established treatment in Germany, and how much it helps beyond a sham treatment is still being studied.

Myth 6: Relief is immediate and permanent

Verdict: false on both counts. Relief builds over weeks, and the DEGRO guideline says the effect should be judged after 2 to 3 months^[3]. Nor is relief shown to be permanent: in LoRD-KNeA, the 3 Gy advantage over sham was present at 8 months and no longer statistically significant at 12 months^[10]. Some patients keep relief much longer, and some programs consider a second course if symptoms return, but no study shows that relief lasts for good. Our how long page has the timing numbers, and our after LDRT page covers what happens when relief fades.

Myth 7: I will lose my hair and feel sick like chemotherapy

Verdict: false. Chemotherapy is a drug that travels through your whole body. LDRT is a beam aimed at one joint, present only while the machine runs. Hair loss is not a reported side effect of LDRT for osteoarthritis. The Korean trial of 114 knee patients reported no treatment-related toxicities^[10], and the ArthroRad trial reported no side effects^[9]. Hair loss from radiation comes from much higher doses passing through hair-bearing skin, such as whole-brain treatment, and hair loss from chemotherapy comes from drugs that reach the whole body. A low dose to a knee, hip, or hand is neither.

The same goes for feeling sick. LDRT involves no drug, and neither trial reported treatment-related illness. The effects that have been reported, including temporary skin irritation and nail reactions, are on our side effects page.

References:
1. Memorial Sloan Kettering Cancer Center. Answers to Common Questions about Radiation Safety. (external-beam therapy does not make a person radioactive in any way; the radiation is present only when the linear accelerator is operating; a person cannot contaminate or transfer radiation to another person). MSK
2. International Atomic Energy Agency. Radiotherapy: what patients need to know. (external beam radiotherapy does not make patients radioactive). IAEA
3. Ott OJ, Niewald M, Weitmann HD, et al; German Cooperative Group on Radiotherapy for Benign Diseases (GCG-BD). DEGRO guidelines for the radiotherapy of non-malignant disorders. Part II: Painful degenerative skeletal disorders. Strahlentherapie und Onkologie. 2015;191(1):1-6 (single doses of 0.5 to 1.0 Gy and total doses of 3.0 to 6.0 Gy per series, 2 to 3 fractions per week; effect judged after 2 to 3 months). PubMed
4. Reuters Health Rounds, reporting the ASTRO 2025 annual meeting, September 30 and October 1, 2025 (postoperative radiation doses after surgery for breast and head and neck cancers typically range from 45 to 60 Gy). Reuters
5. University of Alabama at Birmingham, Heersink School of Medicine. Expanding access: UAB Radiation Oncology offers low-dose radiation therapy for osteoarthritis. (low doses decrease inflammatory markers; treatment does not regrow cartilage, but can alleviate discomfort). UAB
6. American Society for Radiation Oncology. Low-dose radiation therapy offers substantial relief to people with painful knee osteoarthritis. News release, 2025, on the LoRD-KNeA trial (for severe osteoarthritis, where the joint is physically destroyed and cartilage is already gone, radiation will not regenerate tissue). ASTRO
7. Dove A, Koneru B, Small W Jr, et al. American Radium Society (ARS) Appropriate Use Criteria (AUC) for Low-Dose Radiotherapy for Treatment of Osteoarthritis. American Journal of Clinical Oncology. 2026 (548 articles identified, 44 included, 8 more from citation searches, 52 studies in all; overall response rate 60% to 90%; further high-quality studies warranted). PubMed
8. Minten MJM, Leseman-Hoogenboom MM, Kloppenburg M, et al. Lack of beneficial effects of low-dose radiation therapy on hand osteoarthritis symptoms and inflammation: a randomised, blinded, sham-controlled trial. Osteoarthritis and Cartilage. 2018;26(10):1283-1290. DOI
9. Niewald M, Moumeniahangar S, Müller LN, et al. ArthroRad trial: randomized multicenter single-blinded trial on the effect of low-dose radiotherapy for painful osteoarthritis, final results after 12-month follow-up. Strahlentherapie und Onkologie. 2024 (standard dose 3.0 Gy vs experimental 0.3 Gy; favorable pain relief in both arms, no significant difference between arms; side effects did not occur). PMC
10. Kim BH, Ro DH, Wang JH, et al. Single course low-dose radiation therapy in knee osteoarthritis (LoRD-KNeA): a randomized controlled trial. BMC Medicine. 2026 (114 patients; responder rate at 4 months 70.3% at 3 Gy vs 41.7% sham; advantage present at 8 months, no longer statistically significant at 12 months; no treatment-related toxicities reported). BMC Medicine