Inhomogeneity of gated and ungated SPECT technetium-99m-sestamibi bull's-eyes in normal dogs: comparison with thallium-201.
By computer simulation, we have previously hypothesized, independent of the isotope imaged, that differences in view-to-view resolution and attenuation patterns predictably cause count density distortions in SPECT images. We tested the simulation predictions for both ECG-gated and ungated SPECT 99mTc-sestamibi and SPECT 201Tl myocardial perfusion images in normal dogs. In agreement with the predictions of the computer model, distortions in SPECT 99mTc-sestamibi myocardial perfusion images are virtually equivalent to SPECT 201Tl, dependent on the exact SPECT acquisition orbit and markedly different for a posterior 180 degrees acquisition arc compared to an anterior 180 degrees acquisition arc. Furthermore, ungated and gated SPECT 99mTc-sestamibi images show similar count inhomogeneities. These results suggest that little is to be gained from a 360 degrees acquisition with SPECT 99mTc-sestamibi, and that image distortions from gated or ungated SPECT 99mTc images with 180 degrees orbits will be similar to those in SPECT 201Tl images.
Eisner
R L
RL
Carlyle Fraser Heart Center, Crawford Long Hospital, Emory University, Department of Nuclear Cardiology, Atlanta, GA 30365.
Martin
S E
SE
Leon
A R
AR
Schmarkey
L S
LS
Worthy
M A
MA
Chu
T H
TH
Patterson
R E
RE
D000241:Adenosine / Q000008:administration & dosage; D000818:Animals; D003198:Computer Simulation; D004285:Dogs; D004562:Electrocardiography; D006321:Heart / Q000000981:diagnostic imaging*; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine