Improved SPECT using simultaneous emission and transmission tomography.

TLDR

The authors propose a simultaneous emission–transmission SPECT technique that generates a body attenuation coefficient map. They acquire dual‑radionuclide data with a low‑energy transmission source on a rotating gamma camera, subtract predicted emission scatter from the transmission window, and reconstruct the transmission image to obtain the attenuation map. Experimental results show the method estimates attenuation coefficients within ±2.5 % in phantoms and patients without added scan time, and yields attenuation‑corrected activity estimates accurate to better than 5 %.

Abstract

A method is proposed to simultaneously record single photon emission and transmission tomographic (SPECT) studies to produce a map of attenuation coefficients (mu) for the body. A dual radionuclide SPECT acquisition is performed with a transmission source attached to a rotating gamma camera of lower energy than the emission radionuclide. Scatter from the emission source into the transmission window is removed by subtracting the predicted scatter distribution. The transmission image is then reconstructed to yield the map of attenuation coefficients for anatomic display or attenuation correction purposes. Experimental work has shown that the method can accurately derive mu values to +/- 2.5% in both phantom and patient studies, without increasing acquisition time. Preliminary attenuation correction experiments have demonstrated an accuracy of better than 5% for estimated activity.