TY - JOUR
T1 - Application of pixel truncation to reduce intensity artifacts in myocardial SPECT imaging with Tc-99m tetrofosmin
AU - Funahashi, Masao
AU - Shimonagata, Tsuyoshi
AU - Mihara, Kazuhiro
AU - Kashiyama, Kazuyuki
AU - Shimizu, Ryuichi
AU - Machida, Shuzo
AU - Izumi, Kazuyuki
AU - Kusuoka, Hideo
AU - Nishimura, Tsunehiko
AU - Hoki, Noritake
AU - Kawamoto, Sei Ichi
PY - 2002
Y1 - 2002
N2 - Background. Technetium 99m-lauibeled radiopharmaceuticals accumulate in the liver and gallbladder, where they generate intensity artifacts that can result in misdiagnosis of myocardial single photon emission computed tomography (SPECT) images. This study identifies and eliminates factors affecting the magnitude and appearance of intensity artifacts in a gallbladder-heart phantom. Methods and Results. The myocardium and background compartments of a phantom were filled with Tc-99m at concentrations of 320 and 26.1 kBq/mL, respectively. A disposable plastic syringe containing 5 mL of Tc-99m as a model of the gallbladder was fixed in a position lateral to the heart phantom. Artifact intensity was determined on SPECT images over a specific activity range in the syringe (28.6, 6.6, and 0.2 MBq/mL). Among 72 projection images, those with maximal heart counts in the region of interest were selected. Counts above and below 110% of the maximal heart count in all projection images were excluded and reconstructed, respectively. At 28.6 and 6.6 MBq/mL, excessive artifacts generated cold pixels immediately around the source, whereas lower activity (0.2 MBq/mL) caused the artifacts to disappear. Truncating the counts in the gallbladder caused the intensity artifacts at specific activities of 28.6 and 6.6 MBq/mL to disappear. Conclusions. The magnitude and appearance of intensity artifacts depend on contrast between extracardiac activities in the same slices of the heart in myocardial SPECT images with Tc-99m tetrofosmin, and pixel truncation can eliminate them.
AB - Background. Technetium 99m-lauibeled radiopharmaceuticals accumulate in the liver and gallbladder, where they generate intensity artifacts that can result in misdiagnosis of myocardial single photon emission computed tomography (SPECT) images. This study identifies and eliminates factors affecting the magnitude and appearance of intensity artifacts in a gallbladder-heart phantom. Methods and Results. The myocardium and background compartments of a phantom were filled with Tc-99m at concentrations of 320 and 26.1 kBq/mL, respectively. A disposable plastic syringe containing 5 mL of Tc-99m as a model of the gallbladder was fixed in a position lateral to the heart phantom. Artifact intensity was determined on SPECT images over a specific activity range in the syringe (28.6, 6.6, and 0.2 MBq/mL). Among 72 projection images, those with maximal heart counts in the region of interest were selected. Counts above and below 110% of the maximal heart count in all projection images were excluded and reconstructed, respectively. At 28.6 and 6.6 MBq/mL, excessive artifacts generated cold pixels immediately around the source, whereas lower activity (0.2 MBq/mL) caused the artifacts to disappear. Truncating the counts in the gallbladder caused the intensity artifacts at specific activities of 28.6 and 6.6 MBq/mL to disappear. Conclusions. The magnitude and appearance of intensity artifacts depend on contrast between extracardiac activities in the same slices of the heart in myocardial SPECT images with Tc-99m tetrofosmin, and pixel truncation can eliminate them.
KW - Intensity artifacts
KW - Pixel truncation
KW - Technetium 99m tetrofosmin
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U2 - 10.1067/mnc.2002.126682
DO - 10.1067/mnc.2002.126682
M3 - Article
C2 - 12466787
AN - SCOPUS:0036868703
SN - 1071-3581
VL - 9
SP - 622
EP - 631
JO - Journal of Nuclear Cardiology
JF - Journal of Nuclear Cardiology
IS - 6
ER -