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Neutron Therapy Program

Woman sitting in chair.
Woman demonstrating the application of the Cyclotron’s horizontal neutron beam for cancer therapy (1977).

In the mid-1970s, the Cleveland Clinic began using the Cyclotron Facility for an experimental neutron therapy cancer treatment program that lasted until 1990.


In 1975, the Cleveland Clinic Foundation partnered with the Lewis Research Center to use the cyclotron to treat cancer patients using neutron therapy. This was part of a larger national research program that sought to compare the use of fast neutrons to destroy tumors to the use of traditional x-ray radiation. New areas were added to the Cyclotron Facility to accommodate the medical personnel and patients. In 1981, Lewis turned over operation of the Cyclotron to the Clinic. Under a new grant, the Clinic continued treating patients until 1990.


Partnership with the Cleveland Clinic

The concept of using fast neutrons from cyclotrons to attack cancer cells arose in the 1930s, but it was not until the mid-1960s that studies showed promising results for some types of tumors. It was theorized that, compared to gamma rays, the fast neutrons caused denser ionization which was more damaging to cancer molecules.

Several institutions undertook clinical studies in the early 1970s, as the cancellation of NASA’s nuclear program in early 1973 significantly reduced use of the Cyclotron. As part of an effort to get non-NASA organizations to use the Cyclotron, Dr. James Blue approached University Hospitals and the Cleveland Clinic about the feasibility of using the Lewis Cyclotron for neutron therapy.

Dr. Antonio Antunez, head of the Cleveland Clinic’s Radiation Therapy, responded positively to the offer in 1975. Formal negotiations between NASA and the Cleveland Clinic began in June 1976, resulting in the development of schedules and identification of the required equipment. The National Cancer Institute (NCI) agreed to provide a 3-year $519,000 grant, and the Cleveland Clinic provided $200,000 to modify the Cyclotron Building to accommodate medical personnel and patients. As a subcontractor for the Clinic, Lewis agreed to operate the cyclotron for four 8-hour days each week.


Modifications to the Facility

Although there were no significant modifications to the 69-inch diameter accelerator, the Neutron Therapy Program required a number of changes to the facility. A Neutron Therapy Control Room was constructed off the southwest corner of the Cyclotron Facility. This required new excavation and the addition of a stairwell leading to the aboveground parking lot. The new control room allowed medical personnel to remotely perform patient treatments; the actual cyclotron continued to be operated from the control room in the Materials and Stresses Building basement.

The Target Room was converted into a Therapy Room that housed two collimators and various medical equipment to treat to the patients. The Lewis cyclotron was unique in its use of both a vertical and a horizontal collimator for more specific treatment options.

New magnetic steering devices were installed inside the Vault Room to guide the particle beam into a splitter, which directed it either into the Therapy Room to the horizontal collimator or through the roof into the new room built above. This Mechanical Equipment Room contained steering equipment that rerouted the particle beam downward to the vertical collimator in the Therapy Room below.

Rooms in the Materials and Stresses Building basement were converted into waiting and examination rooms and calibration labs. The Cleveland Clinic also sought to improve the patient experience by adding colorful curtains and wall murals to the otherwise drab facility.

Physical construction was completed in the spring of 1977, followed by installation of the beam control equipment that summer, and calibration and training on computer and control systems in the fall. The first patient was treated on November 17, 1977.



NASA-Cleveland Clinic Collaboration

The Cleveland Clinic’s experimental program aimed to determine if the use of fast neutrons was more effective than traditional radiation for the treatment of certain cancers. Doctors throughout the Midwest selected patients for the program. These individuals had to have non-spreading tumors that had not responded to traditional treatments.

Each patient arrived at Lewis on Tuesdays and Thursdays. A Cleveland Clinic physician determined the proper dose of radiation while a nurse or technician set up the patient at either the horizontal or vertical collimator. With the former, the beam was delivered horizontally to the targeted area as the patient sat upright in a chair. The latter method—unique to the Lewis Cyclotron—aimed the beam downward vertically to a patient lying flat on a gurney. This direction was effective for treatment of thorax and pelvis tumors.

The physician in the new control room transmitted the requested radiation levels to facility operators in the cyclotron control room.  The accelerator bombarded a beryllium target with a 25 MeV deuteron beam to bombard to generate the fast neutrons sent to the Therapy Room. The medical staff monitored the patient remotely throughout the process. The computer automatically terminated the beam when the correct amount of radiation was met.

During a 6-week cycle, each patient would undergo two experimental treatments at Lewis and three x-ray therapies at the Cleveland Clinic per week. The Cyclotron treated over 300 patients with 6,500 exposures between November 1977 and September 1980.



NCI-Cleveland Clinic Therapy Program

NASA’s continued budget reductions throughout the 1970s put significant restraints on Lewis’ staffing and operating funds. As the original agreement with the Cleveland Clinic wound down in 1980, the center offered the Cleveland Clinic the opportunity to completely take over the operation of the Cyclotron.

In 1981, the Cleveland Clinic obtained a $2.5 million, 5-year grant from the NCI to expand its neutron therapy program and take over operations. Four Lewis employees heavily involved with the cyclotron—Dr. James Blue, Donald Evancic, Francis Kebberly, and William Roberts—retired from NASA and joined the Cleveland Clinic staff.

The Cleveland Clinic’s efforts were now part of the NCI’s national program to study the use of fast neutrons for cancer treatment. Each of the participating institutions employed slightly different tactics. The Cleveland Clinic program used a particle beam consisting of 40 percent neutrons and 60 percent conventional radiation. In addition to the neutron treatments, the Cleveland Clinic also experimented with particles from cobalt 60 for cancer treatments.

In 1988 the NCI decided to end the program to concentrate on treatments that did not involve radiation. The Lewis cyclotron had treated 1200 of the 4000 patients in the national program. During this period, the cyclotron also supported NASA and university research programs and produced isotopes for medical applications.

On July 30, 1990 the Cleveland Clinic informed NASA it was ceasing its neutron therapy work and would end operations in November. Blue and Kebberly retired, while Evancic and Roberts continued to work in the Clinic’s department of radiation therapy.




The medical community remains divided on the benefits of neutron therapy. Neutron beams are more powerful than electron or photon beams, so shorter doses are necessary. They are also more apt to damage both strands of DNA in cancer cells.

The neutrons, however, also damage healthy cells, so the beam must be highly focused precisely applied.  The University of Washington—participant in the NCI study—continues to successfully use neutron therapy to treat salivary gland cancer.

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