Access to medical radioisotopes spurs new research into disease

Chin-Tu Chen and Cyclotron

UChicago Medicine is the only academic health system in Illinois with an operational cyclotron. A cyclotron is a machine that accelerates a particle along a spiral path. The particle’s energy increases as it circulates through the machine. Once it has gained enough energy, the particle hits a target and a nuclear reaction occurs, producing a radioactive element of interest. The cyclotron is giving current doctors and patients access to care and diagnoses, but also spurring new lines of inquiry and research that can lead to new understanding of and treatments for disease. 

The UChicago Cyclotron Facility produces both the radioactive isotope, which decays via positron emission, thus creating gamma rays for PET imaging, and the drug that contains the isotope. How does PET work? A PET scan creates images of the body, allowing a radiologist to evaluate abnormalities in processes such as metabolism, blood flow or chemical absorption. The images are taken using a special camera that captures gamma rays—electromagnetic radiation that is invisible to the naked eye. The gamma rays are produced inside the body, through the interaction of a specialized drug and naturally occurring particles within the body’s tissues.

The drug, given to a patient before their scan, acts as a sort of Trojan horse. For instance, the drug may look to the body like glucose, in which case a region that needs energy, like a growing tumor, will readily use it. But the drug isn’t really glucose. It’s a mimic, and it contains a radioactive isotope that emits positrons. When these positrons, or anti-electrons, interact with electrons in the body, they annihilate, releasing gamma rays. So, as the tumor is trying to utilize the drug, it is also enabling physicians to see, study and ultimately, attempt to eliminate the tumor.

The UChicago Cyclotron Facility produces both the radioactive isotope, which decays via positron emission, thus creating gamma rays for PET imaging, and the drug that contains the isotope. Once the isotope is produced in the cyclotron, it is transported to a cleanroom, containing a hot cell, a chamber shielded by three inches of lead. There, radiochemist Mohammed Parvez Bhuiyan and radiochemistry specialist and cyclotron operator Anna Kucharski synthesize the drug.

Dr. Chin-Tu Chen (Medical Physics), the facility’s scientific director, envisioned and gained support from the Biological Sciences Division’s Dean’s Office, the University of Chicago Comprehensive Cancer Center, the Duchossois Foundation, the O’Connor Foundation, and the Ludwig Foundation. Current Medical Physics PhD students Brittany Broder and Inna Gertsenshteyn are using the cyclotron to investigate the development and kinetic analysis of emerging PET radiotracers and the multi-modal imaging of tumor hypoxia.

Read the full story in "UChicago Cyclotron Facility reinvigorates nuclear medicine in Illinois" by Amanda Parker published November 2, 2021

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