Doctors at Mayo Clinic have begun testing whether very low doses of radiation, aimed at small parts of the brain, can slow Parkinson’s disease by calming inflammation1. The study is small: it plans to enroll 20 people with early-stage Parkinson’s1. Mayo Clinic describes it as the first clinical trial to test low-dose radiation as an anti-inflammatory treatment for early Parkinson’s2.
No results exist yet. The researchers themselves say the treatment’s effectiveness has not been established2.
What happened
The trial is registered on ClinicalTrials.gov, the US public database of clinical studies, under the number NCT07218952, with Mayo Clinic as its sponsor3. The record was first posted on October 21, 2025, and lists a start date of January 20, 20263. Its status is “enrolling by invitation,” and participants are being treated at Mayo Clinic in Rochester31. News of the trial reached the public this month through a Mayo Clinic press release and coverage that followed12.
“Instead of treating the symptoms patients experience, we’re investigating whether low-dose radiation can affect one of the underlying biological processes associated with the disease and therefore slow the worsening of symptoms,” said Yasamin Sharifzadeh, a radiation oncologist at Mayo Clinic and the trial’s lead investigator1.
Why doctors are looking at inflammation
Parkinson’s slowly destroys nerve cells that make dopamine, a brain chemical that helps control movement1. That loss leads to tremors, stiffness, slowed movement and trouble with balance, and people can also have fatigue, depression, anxiety and changes in thinking2. The disease is also linked to a build-up of abnormal proteins in and around brain cells2.
Today’s treatments, including medicines and procedures such as deep brain stimulation, can ease symptoms, but none can stop the disease from getting worse1. The cause is not fully understood, and researchers think several biological changes may play a part. One of them is inflammation in the brain, sometimes called neuroinflammation1.
“Parkinson’s disease is not a single uniform condition but rather a collection of related disease subtypes that may differ biologically,” said Rodolfo Savica, a Mayo Clinic neurologist working on the study2. He added that this “complicates the search for a universal treatment, but despite this complication, inflammation appears to play a meaningful role across many forms of the disease”2.
How the trial works
Radiation is usually given at high doses to kill cancer cells. Here, the idea is to use far lower doses on small brain areas thought to be involved in Parkinson’s, to see whether that has a different effect1. “The goal is not to destroy brain tissue but to investigate whether radiation can reduce inflammatory processes in specific parts of the brain,” Sharifzadeh said1. The treatment is limited to those chosen areas rather than the whole brain2.
The steps, as described in the registry and coverage:
- Planning. Each person gets an MRI scan and a DaT-SPECT scan, an imaging test that shows how much of the brain’s dopamine system is still working. Doctors use these to pick the target areas31. Blood samples are taken to measure biomarkers, lab signals that track disease processes2.
- Treatment. One radiation session a day for five days in a row, each lasting about 10 to 15 minutes, delivered by a standard hospital radiation machine called a linear accelerator13.
- Follow-up. Researchers check inflammation markers and abnormal protein build-up six hours after treatment, then at three, six and 12 months2. Brain scans track dopamine loss, and doctors monitor movement, thinking and mood over time12.
The trial’s main measure is the change in disease progression from the start to six months3. According to the registry details reported by Parkinson’s News Today, the team will look for a seven-point drop in movement-symptom scores after six months, using Part III of a standard doctor-rated Parkinson’s scale (the MDS-UPDRS)1. They will also track those scores and quality of life at three and six months1.
Who is in the study
The trial is for people with early Parkinson’s that has no known genetic cause4. Entry rules in the registry include a diagnosis from a movement-disorder neurologist, a DaT scan confirming the disease affects one side of the body, and a low score on a standard scale of disease stage4. People with dementia or memory concerns, or whose Parkinson’s medicines changed in the last three months, are excluded4. Participants must agree to give blood samples for research and to return to Mayo for follow-up4.
Sources differ on the age range. The trial registry and Parkinson’s News Today give ages 45 to 7041, while NR Times reported 45 to 752.
What it will not show
This is an early, exploratory study, and its design limits what it can tell anyone:
- No comparison group. All 20 participants get the radiation, and everyone knows it; there is no placebo (dummy treatment) group4. Parkinson’s symptoms can vary over time, and people’s expectations can affect how they feel and score, so changes seen without a comparison group are hard to pin on the treatment.
- Small and short. Twenty people followed for up to a year cannot reveal rare side effects or show whether any effect lasts.
- A narrow group. Only people with early disease on one side of the body and no known genetic cause are included4, so results may not apply to other people with Parkinson’s.
- Not a formal drug-style phase. The registry lists the trial’s phase as “not applicable,” a label often used for studies of procedures rather than drugs3.
Sharifzadeh framed the study as a first step. “Parkinson’s disease is multifaceted, and there is still much we are learning about the role inflammation plays in the disease,” she said2. “The findings could help determine whether this approach should be studied further and add to our understanding of the foundational biological mechanisms in Parkinson’s disease”2.
Who is behind it
Mayo Clinic is the trial’s sponsor3. The registry lists its funding as “other,” meaning it is not listed as funded by industry or a US government agency4. No drug or device company is named as a backer in the sources, and none of them report financial conflicts of interest for the investigators. Sharifzadeh, a radiation oncologist, leads the trial, and Savica, a neurologist, is a study investigator2.
What to watch next
The registry lists October 2027 as the expected date for the main results, and no results have been posted yet3. Things to look for:
- whether the team reports on safety, since radiation to the brain, even at low doses, needs careful study;
- whether movement scores and brain scans change at six months, and whether lab signs of inflammation fall;
- whether any promising signal leads to a larger trial with a comparison group, which would be needed before anyone could say the approach slows Parkinson’s.
Until then, the trial is a test of an idea, not a treatment. It asks whether a tool built for cancer can be used in a much gentler way to aim at one of the processes researchers think drives Parkinson’s1.
