SPECT/MR Debuts as New Hybrid Modality

SPECT/MR debuted this week as a new preclinical hybrid molecular imaging system with promises of higher resolution and lower dose.

The single photon emission tomography and magnetic resonance system was introduced at the Society of Nuclear Medicine and Molecular Imaging’s 2013 annual meeting in Vancouver, British Columbia.

"We are pioneering simultaneous SPECT and MR imaging technologies now demonstrated in preliminary small animal studies," Benjamin M.W. Tsui, PhD, director of the division of medical imaging physics in the department of radiology, and a professor of radiology, electrical and computer, biomedical engineering, and environmental health sciences at Johns Hopkins University in Baltimore, Md., said in a statement.

Tsui and colleagues have been building the technology for five years with TriFoil Imaging, formerly the preclinical business of Gamma Medica Inc.

“This presents a unique multimodality system that images mice down to a spatial resolution of less than1 mm at high detection efficiency," he said.

SPECT/MR is different from other hybrid modalities because it allows for imaging with biomarkers labeled with a wide range of radionuclides. SPECT/MR has a variety of potential applications, including imaging for cancer, cardiovascular and neurological diseases, thyroid and other endocrine disorders, trauma, inflammation and infection, officials said.

Developers integrated 16 x16 pixel and 1.6 mm pixel pitch cadmium zinc telluride (CZT) solid-state detectors that directly convert incoming photons into electrical signals that are not affected by the static magnetic field. The SPECT insert also houses a "multi-pinhole" collimator that provides both high spatial resolution and capacity for the detection of photons from small animals injected with available or novel nuclear medicine biomarkers that use radionuclides to convey physiological functions of the body.

SPECT/MR also elimates the dose associated with CT and comes at a lower cost than PET/MR, Tsui said. However, the technology is not intended to replace other modalities, but instead to provide biomedical investigators and clinicians more options for optimizing research and patient care, he added. SPECT/MR is expected to be tested in human trials soon.

"We are confident that with sufficient funding we can build a SPECT/MR system for human brain studies in about two years and begin clinical studies by the third year," Tsui said.