Radiation-free Imaging Method Efficiently Diagnoses Cancer

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According to a study recently published in The Lancet Oncology, researchers from Stanford University School of Medicine in California tested a new whole-body diffusion-weighted magnetic resonance imaging (MRI) technique.

The imaging method uses ferumoxytol, an iron supplement, to significantly improve the visibility of tumors. Ferumoxytol consists of tiny superparamagnetic iron oxide particles that can be detected when using MRI.

Typical imaging systems, such as PET and CT scans, are used to evaluate the development of cancer in children. However, these imaging techniques can expose children to radiation that raises their risk of secondary cancers later in life. Now, this new research has outlined a novel whole-body imaging technique that could eliminate such a risk.

The research team, led by Dr. Heike Daldrup-Link, recognizes that computed tomography (CT) and F-fludeoxyglucose (18F-FDG) positron emission tomography (PET)/CT scans are the prime methods employed to see what stage cancers are at and to assess the best treatment plan.

However, Daldrup-Link notes previous research has shown the secondary cancer risks linked with these techniques.

According to the study background, ionizing radiation, high frequency radiation that has enough energy to damage cells' DNA, in early childhood has been demonstrated to triple the risk of lifetime cancer, as opposed to adults exposed to the radiation from the age of 30.

Moreover, the researchers note that growing radiation exposure from diagnostic CT scans may almost triple the risk of secondary leukemia and brain cancer later in life.

Daldrup-Link illuminates the point that children are much more sensitive to radiation than adults are, and are more likely to experience secondary cancers because they will live for a longer period following exposure.

The researchers wanted to see how their new whole-body MRI technique, which uses no radiation exposure, would match up in terms of diagnostic precision with the standard F-FDG PET/CT approach.

The investigators utilized both the whole-body MRI and F-FDG PET/CT to scan 22 children and young adults aged between 0 and 33 years who had malignant lymphomas and sarcomas.

Mean radiation exposure was verified as zero for the whole-body MRI technique, while the F-FDG PET/CT method exposed patients to 12.5 millisieverts (mSv).

The investigators discovered that the diagnostic accuracy of the whole-body MRI technique was 97.2%, as opposed to 98.3% in the F-FDG PET/CT technique. The whole-body MRI also exhibited similar sensitivities and specificities to the F-FDG PET/CT, at 93.7% vs. 90.8% and 97.7% vs. 99.5%, respectively.

"Present techniques used for diagnosis and treatment, albeit effective, might bear certain risks and thus do not meet our high standards on patient care. This new imaging test might solve this conundrum of the need for diagnostic cancer staging procedures and concurrent risk of secondary cancer development later in life,” the researchers commented on their findings.

Yet, in a comment piece connected to the study, Thomas C. Kwee, of the University Medical Centre Utrecht in the Netherlands, notes that “although the new whole-body MRI technique has shown success in this study, further work is needed before it can become a clinical alternative to F-FDG PET/CT."

Daldrup-Link acknowledges such claims and states that the research team plans to conduct and gather further research regarding the study.

She noted the team has already formed a collaboration with six centers in the US, including the University of California, San Francisco, and Stanford University, in order to test the new MRI imaging method against radiotracer-based staging examinations.

"We are in the process of applying for funding at the moment and if all goes well, might be able to start the multi-center trial this fall. We already received requests from two centers in Europe who want to join in as well," said Daldrup-Link.