K. Nakajima et al., Superiority of triple-detector single-photon emission tomography over single- and dual-detector systems in the minimization of motion artefacts, EUR J NUCL, 25(11), 1998, pp. 1545-1551
Citations number
16
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
A patient motion-related artefact is one of the most important artefacts in
single-photon emission tomography (SPET) imaging. This study evaluated the
effect of the number and configuration of SPET detectors on motion artefac
ts. The following acquisition conditions were simulated based on original 3
60 degrees projection images: (1) single-detector 180 degrees rotation (S18
0), (2) a dual-detector rectangular (L-shaped) 180 degrees acquisition (D18
0L), (3) dual-detector cameras mounted opposite each other with 360 degrees
acquisition (D360) and (4) triple-detector 360 degrees acquisition (T360).
The motion artefacts were introduced using a syringe and a myocardial phan
tom. Clinical cases with technetium-99m methoxyisobutylisonitrile and thall
ium-201 studies were analysed to confirm the validity of this phantom simul
ation. The effect of continuous alternate rotation acquisition and summing
the projections on the reduction of motion artefacts was investigated in ea
ch model. The effect of motion depended on the number and the configuration
of the SPET detectors. A 1-pixel (6.4 mm) motion in the S180, D180L and D3
60 models generated only slight artefacts, and a 2-pixel motion led to an a
pparent decrease in activity or created hot areas in the myocardium. On the
other hand, a T360 rotation created few artefacts even with a 2-pixel moti
on of the last quarter of the projections. Despite the difference in attenu
ation with Tl-201 and Tc-99m, similar artefact patterns were observed with
both radionuclides in selected patient model studies. Continuous alternate
rotation could reduce artefacts caused by less than a 2-pixel motion. In co
nclusion, calculating the average of the sum of the projections of triple-d
etector 360 degrees rotations with alternate rotation is the best method to
minimize motion artefacts. This "averaging" effect of motion artefacts is
a key to this simulation.