Feature | June 11, 2014

Radioluminescence Tells the Story of Single Cells

SNMMI Radioluminescence Single Cells Nuclear Imaging

June 11, 2014 — With a new molecular imaging system powerful enough to peer down to 20-micrometer resolution, researchers can now use radioluminescence to examine the characteristics of single, unconnected cells. The result is a fascinating picture of diversity among cells previously assumed to behave the same, revealed researchers at the Society of Nuclear Medicine and Molecular Imaging’s 2014 Annual Meeting (SNMMI).

A resolution of 20 micrometers or microns — about a quarter of the diameter of a single human hair — is made possible with an imaging technique that unites the physics of nuclear medicine with optical imaging. Researchers inject a radioactive material that acts upon an ultrathin scintillator, which fluoresces when it detects charged particles. The fluorescent signal is then picked up by a specialized radio-luminescence microscope.

“Our research seeks to answer the question: In a population of cells, how important is individuality? Are the cells so similar that just knowing the average of a cell population is sufficient, or is there a need to look at individual cells, one by one?” These are the questions being answered by Guillem Pratx, Ph.D., assistant professor of radiation physics and radiation oncology at Stanford University, Stanford, Calif., and principal investigator of the clinical study.

Imaging the physiological functions of the body is possible with radiotracers, imaging agents that combine a radioactive material and molecular compound that interacts with biochemical processes. For this study, radiotracers interact with live cells viewed by radio-luminescence microscopy. The specialized microscope’s CdWO4 scintillator captures beta particles as they are emitted by the radiotracer in the cell sample. By compiling these atomic events, the scintillator can reconstruct the data into an image that nuclear medicine physicians use to interpret disease pathology and response to drug treatment.

“Our goal is to characterize radiotracers from the perspective of how they interact with single cells,” said Pratx. “The conventional methods used in nuclear medicine use large numbers of cells to produce measurements of cellular characteristics, because they do not have the spatial resolution to see single cells. Very little research, if any, has looked at what happens at the scale of a single cell.”

The innovation of this particular microscope is not only its detector but also to its ability to capture optical brightfield and fluorescence images. The two models differ only by their lens — one includes a commercial grade 0.2X tube lens and the other a custom 1X tube lens.

Researchers used these systems to image how single breast cancer cells used a radiotracer called F-18 fluorodeoxyglucose (F-18 FDG), a molecular compound that mimics glucose as fuel for cellular processes. The breast cells showed unexpected and intense variation. The team also imaged a human antigen called CD20, which can signal cancer of the blood, or lymphoma, on a transplanted sample of small animal spleen tissue, and assessed how the sample responded to a simultaneous radionuclide and antibody lymphoma therapy called Zr-89 Rituximab. The radioluminescence microscope was able to clearly visualize the expression of CD20 from malignant B cells in the spleen sample.

“This new tool will help nuclear medicine and molecular imaging advance toward more personalized radionuclide imaging,” Pratx explained. “Since we are able to see how properties of single cells impact their interaction with radiotracers, there is an opportunity to develop new radiotracers that are biologically optimized to target specific disease pathways.”

Further studies are required to validate the research for radioluminescence microscopy in order to secure regulatory approval for commercial use.

For more information: www.snmmi.org

Related Content

GE Healthcare Recalls Millennium Nuclear Medicine Systems
News | Nuclear Imaging | November 15, 2018
GE Healthcare announced it is recalling its Millennium Nuclear Medicine Systems due to an incident in which the the top...
Artificial Intelligence Predicts Alzheimer's Years Before Diagnosis
News | Neuro Imaging | November 14, 2018
Artificial intelligence (AI) technology improves the ability of brain imaging to predict Alzheimer’s disease, according...
Researchers Awarded 2018 Canon Medical Systems USA/RSNA Research Grants
News | Radiology Imaging | November 13, 2018
The Radiological Society of North America (RSNA) Research & Education (R&E) Foundation recently announced the...
Subtle Medical Showcases Artificial Intelligence for PET, MRI Scans at RSNA 2018
News | Artificial Intelligence | November 13, 2018
At the 2018 Radiological Society of North America annual meeting (RSNA 2018), Nov. 25-30 in Chicago, Subtle Medical...
University of Missouri Research Reactor First U.S. I-131 Supplier in 30 Years

MURR is the only supplier of I 131 in the United States and the first U.S. supplier since the 1980s. Image courtesy of University of Missouri

News | Radiopharmaceuticals and Tracers | November 13, 2018
The University of Missouri Research Reactor (MURR) recently shipped its first batch of Iodine-131 (I-131), a...
MEDraysintell Projects Increasing Mergers and Acquisitions in Nuclear Medicine
News | Nuclear Imaging | November 07, 2018
With the recent announcement by Novartis to acquire Endocyte , interest from the conventional pharmaceutical industry...
A PET/CT head and neck cancer scan.

A PET/CT head and neck cancer scan.

Feature | Nuclear Imaging | November 05, 2018 | By Sabyasachi Ghosh
“Experimental validation implemented in real-life situations and not theoretical claims exaggerating small advantages
PET Imaging Offers New Possibilities in Chronic Liver Disease Management

Hepatic 18F-FDG, 18F-FAC, and 18F-DFA accumulation are affected in a mouse model of autoimmune hepatitis. (A) Histochemical and immunohistochemical analyses of liver sections from vehicle- and ConA-treated mice. Scale bars represent 50 microns. Transverse PET/CT images (B) and quantification (C) of vehicle- and ConA-treated mice injected with 18F-FDG, 18F-FAC, and 18FDFA. Livers are outlined in a white dotted line. Quantification represents radiotracer accumulation in the liver normalized to a background organ. Image courtesy of Salas J.R., Chen B.Y., Wong A., et al.

News | PET Imaging | October 24, 2018
While liver biopsies are powerful and reliable, they are also invasive, painful, limited and subject to complications....
CORAR Supports Medicare Diagnostic Radiopharmaceutical Payment Equity Act of 2018
News | Radiopharmaceuticals and Tracers | October 12, 2018
October 12, 2018 — The Council on Radionuclides and Radiopharmaceuticals Inc.
Huntsman Cancer Institute Installs First Preclinical nanoScan 3T PET/MRI in U.S.
News | PET-MRI | October 10, 2018
The Center for Quantitative Cancer Imaging at Huntsman Cancer Institute (HCI) at the University of Utah in Salt Lake...