Physicians have been utilizing imaging technology that incorporates a positron emission tomography (PET) and computed tomography (CT) scanner to image the body. Advantages of a new imaging system over these hybrid systems include simultaneous imaging, reduced radiation dose, and increased soft tissue contrast.
The US Food and Drug Administration (FDA; Silver Spring, MD, USA) cleared the Siemens Healthcare (Erlangen, Germany) Biograph mMR system, the first device to perform simultaneously a PET scan, and a magnetic resonance imaging (MRI) scan.
“The Siemens PET/MRI system allows two tests to run simultaneously without having to move the patient to a different scanning system,” Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostic Device Evaluation and Safety in the FDA’s Center for Devices and Radiological Health. “Minimizing changes in a patient’s position between tests allows physicians to compare images more easily and helps them get the most accurate information possible.”
The Biograph uses MRI instead of CT to produce detailed images of the internal structures of the body. Because MRI generates images based chiefly on the concentration of water in the body, it can produce greater detail of nearly all the internal structures of the body as compared with CT, which uses X-rays to make images. This could provide the physician with additional data about a patient’s condition.
Moreover, the Biograph mMR system allows physicians to acquire images at a considerably lower radiation dose compared to a PET/CT system. Although the radiation dose from the PET exam remains unchanged, MRI does not use ionizing radiation, so the entire ionizing radiation dose from the CT scan is eliminated. The decreased radiation dose is particularly significant for sensitive populations, such as children or patients who are receiving multiple scans.
The FDA cleared the Siemens system based on bench tests that compared the device with a predicate PET/CT device. The Biograph mMR system is indicated for anyone who needs diagnostic PET or MRI imaging. However, individuals with pacemakers, defibrillators, or other implanted electronic devices should not be scanned with the Biograph mMR system unless those devices are specifically indicated for use in the MRI environment.