SPECT-guided CT enhances bone cancer detection

SPECT/CT is enhancing the detection of cancer in patients, according to results presented this week at SNM’s 53rd Annual Meeting in San Diego.

“The specificity of bone scintigraphy—or bone scanning—is enhanced by combining SPECT with spiral CT,” explained Wolfgang Römer, assistant professor and vice chair of the Clinic of Nuclear Medicine at the University of Erlangen/Nuremberg in Germany. “Because of this technology, the diagnostic process is shortened, reducing stress considerably for individuals waiting for a definite diagnosis,” added the co-author of “Diagnostic Value of Tc-99m-DPD-SPECT/Spiral-CT Hybrid Imaging in Unclear Foci of Increased Bone Metabolism in Cancer Patients.”

Römer said, “With SPECT/CT, the morphologic correlate (form and structure) can be visualized to further clarify findings on bone scintigraphy. We call our procedure ‘SPECT-guided CT.’ ”

“From our study, we conclude that SPECT-guided CT is able to clarify more than 90 percent of findings that were classified as indeterminate in the analysis of SPECT alone. That could mean that in daily clinical practice, additional radiological examinations can be avoided in 90 percent of patients with indeterminate findings in bone scintigraphy,” he said. The German researchers also significantly reduced the CT radiation exposure, according to the study that Römer calls the first report on the benefit of SPECT/spiral CT in bone scintigraphy.

The combination of SPECT and CT was introduced about five years ago but provided non–diagnostic quality CT images, said Römer. “The recently introduced combination of SPECT and spiral CT scanners enables combined SPECT/CT images, which are diagnostic,” he detailed. “With bone scintigraphy alone, it is not possible to differentiate bone metastases (spread) from benign processes causing enhanced bone metabolism,” said Römer. Consequently, additional radiological examinations are regularly recommended to study the metabolic changes. These studies are performed separately and—most often—with a certain time delay, said the nuclear medicine physician and board-certified radiologist. In addition, a radiologist analyzing the separate CT examination may not have detailed information on the scintigraphic findings.

The German researchers used the SPECT/CT system Symbia T2, provided by Siemens Medical Solutions for scientific evaluation.

Römer indicated that the number of patients included in the study was limited, and additional studies with larger patient populations should carefully address the cost efficiency of this new technology and its value in a real clinical setting.

Abstract: W. Römer, A. Noemayr and T. Kuwert, Clinic of Nuclear Medicine, University of Erlangen/Nuremberg, Erlangen, Germany; M. Uder and W. Bautz, Institute of Radiology, University of Erlangen/Nuremberg, Erlangen, Germany, “Diagnostic Value of Tc-99m-DPD-SPECT/Spiral-CT Hybrid Imaging in Unclear Foci of Increased Bone Metabolism in Cancer Patients,” SNM’s 53rd Annual Meeting, June 3–7, 2006, Scientific Paper 251.