Cancer > Alpha vs. Beta Particles: Bigger Particles for Bigger Impact

Alpha vs. Beta Particles: Bigger Particles for Bigger Impact

By Alison Caldwell, Ph.D. Illustrations by Tim West

In theranostics, one area of great interest is the development of alpha-emitting radioisotopes because of their power in targeting and killing cancer cells. But what are alpha particles, and how do these newer therapies compare to the more traditional beta-emitting isotopes?

Alpha vs. Beta Particles

Radiopharmaceutical therapies for treating cancer rely on the particle emission properties of radioactive isotopes for their effectiveness. By combining radioactive isotopes with a targeting molecule, such as an antibody, these treatments can directly target and bind to cancer cells, where they release high-energy particles to kill the tumor. However, not every radioactive isotope releases the same type of particle.

“From a physics standpoint, the beta particles — which are emitted by most currently approved radioisotopes — are basically electrons, while an alpha particle is two neutrons and two protons,” says Oliver Sartor, M.D., medical oncologist and director of Radiopharmaceutical Clinical Trials for Mayo Clinic Comprehensive Cancer Center.

The impact of an alpha versus a beta particle can be compared to a fully loaded semitruck versus a 10-pound dumbbell.

Different kinds of particles have different properties. Understanding these differences can help clinicians and patients make decisions about the most appropriate treatments for an individual’s needs.

“An alpha particle is almost 8,000 times larger than a beta particle," says Dr. Sartor. "In some studies, just one hit from an alpha particle was enough to kill a cancer cell, while it takes many, many hits from beta particles to sufficiently damage a cell’s DNA to kill it.”

To put that into perspective, the impact of an alpha versus a beta particle can be compared to a fully loaded semitruck versus a 10-pound dumbbell.

Precision and Power

Due to their strength, alpha-emitting radioisotopes may benefit patients even when beta-emitting options have failed, and the fact that alpha particles are much larger means that they don’t penetrate as deeply into surrounding tissues, reducing the potential for off-target radiation effects.

As researchers continue to develop new targeted alpha particle treatments and build out the next generation of beta particle therapies, Mayo Clinic is at the forefront of advancing these highly targeted therapies to provide new treatment options for patients. These cutting-edge radiopharmaceuticals hold the potential to significantly improve outcomes for those facing a cancer diagnosis.