[Dual-energy data acquisition for simultaneous 81mKr ventilation/99mTc-MAA perfusion SPECT: ventilation/perfusion ratio mapping in cross section].
Methods of simultaneous pulmonary ventilation/perfusion (V/Q) tomogram (SPECT) for V/Q ratio mapping were reported. Crosstalk was corrected by subtraction assuming crosstalk/signal ratio is constant for an individual examination. Crosstalk was reduced by 85% for that of 99mTc-to-81mKr window (R12), and by 83% for that of 81mKr-to-99mTc window (R21) in a phantom experiment. The R12 and R21 were 1.0-1.9% (mean 1.3%) and 34.6-55.3% (mean 41.9%), respectively in 9 patients (mean age, 56.1 years; range, 38-82 years). V/Q SPECT was undertaken in 7 of the 9 patients. 99mTc-macroaggregated albumin (185 MBq) was injected intravenously in supine position, and 81mKr gas was administered continuously during the SPECT data acquisition. Sixty-four 64 x 64-matrix (size = 8 mm/pixel) images, 20-second acquisition time for each, were collected by a rotating gamma camera in a step-and-shoot fashion during a 360-degree rotation with the two photopeaks, one at 140 keV for 99mTc and another at 190 keV for 81mKr. Examination time was about 40 minutes, and the V/Q ratio maps in cross section were obtained in all of the examinations.
Honda
N
N
Department of Radiology, Saitama Medical Center, Saitama Medical School.
Machida
K
K
Mamiya
T
T
Takahashi
T
T
Kamano
T
T
Kashimada
A
A
Inoue
Y
Y
Osada
H
H
Ban
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007727:Krypton Radioisotopes; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon; D014692:Ventilation-Perfusion Ratio
D007727:Krypton Radioisotopes; D013668:Technetium Tc 99m Aggregated Albumin