[Attenuation corrected myocardial PET after application of 18FDG: effect on the determination of regional myocardial uptake values].
OBJECTIVE
Post injection transmission measurement (PIT) can be performed using rotating 68Ge/68Ga linesources. This study estimates attenuation coefficients, count densities and relative regional uptake values of PIT corrected cardiac PET (E-PIT) compared to routinely pre-injection transmission measurement (RT).


METHODS
A thorax-phantom with homogeneously filled myocardium or with simulated defects and six patients with advanced coronary artery disease were studied using ECAT Exact tomograph (Siemens CTI) equipped with three rotating linesources. Transmission was performed twice (PIT, RT), attenuation coefficients and emission data were analysed, the latter without attenuation correction (E-UK), corrected with PIT (E-PIT) and with RT (E-RT) (count density, standard and relative uptake values).


RESULTS
Both in phantom and patient studies attenuation coefficients differed significantly between PIT and RT. Comparing E-PIT and E-RT, regional uptake values were different only in phantom simulation with myocardial radioactivity concentrations higher than 10 kBq x ml-1. The image contrast between defects and remaining myocardium in the phantom studies or the standard and relative uptake values in patient studies did not vary significantly.


CONCLUSIONS
Under clinical conditions a post injection transmission measurement does not influence the accuracy of regional myocardial uptake values relevantly.
Schulz
G
G
Klinik für Nuklearmedizin, Universitätsklinikum, Deutschland.
Ostwald
E
E
Schreckenberger
M
M
Sabri
O
O
Müller
B
B
vom Dahl
J
J
Büll
U
U
D001692:Biological Transport; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008168:Lung / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D013131:Spine / Q000378:metabolism; D013909:Thorax; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18