RT Journal Article
SR Electronic
T1 A new algorithm to suppress spillover fraction for 11C-Hydroxyephedrine myocardial 3D PET: Non-uniform least squared method with a weighted function using blood time-activity curve
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 2061
OP 2061
VO 52
IS supplement 1
A1 Katoh, Chietsugu
A1 Kasai, Katsuhiko
A1 Yoshinaga, Keiichiro
A1 Manabe, Osamu
A1 Magota, Keiichi
A1 Tamaki, Nagara
YR 2011
UL http://jnm.snmjournals.org/content/52/supplement_1/2061.abstract
AB 2061 Objectives Three-dimensional(3D) PET with 11C-Hydroxyephedrine (HED) yields myocardial image data with much spillover fraction from the blood. To estimate the myocardial sympathetic nerve function using 11C-HED with 3D PET, we developed a new algorithm to suppress the spillover using a non-uniform least squared fitting with a weighted function using a blood time-activity curve. Methods Nine volunteers underwent 2D, 3D 11C-HED PET and 123I-MIBG scintigraphy. 2D and 3D 11C-HED dynamic PET was performed for 40minutes using Siemens ECAT HR+ and Biograph, respectively. A whole myocardial ROI curve, left ventricular ROI curve, the tissue fraction in the myocardial ROI and spillover ratio into myocardial ROI were determined as R(t),LV(t),A and Va, respectively. True curves of the blood Ca(t) and myocardium Ct(t) were estimated as follows; dCt(t)/dt=K1Ca(t)-k2Ct(t),R(t)=ACt(t)+VaCa(t). These were estimated to minimize the weighted error between the curve R(t) and ACt(t)+VaCa(t). The error was calculated as follows; Σ(Ca(t)x(ACt(t)+VACa(t)-R(t))2. It dedicated strict tolerance in the curve fitting during the span of high radioactivity in the blood. Retention index (RI) was estimated using the Ca(t) curve. The myocardial RI estimated with 3D 11C-HED PET data were compared with those from the 2D 11C-HED PET. Results 2D 11C-HED PET dedicated well correlated myocardial RI with Heart / Mediastinal (H/M) ratio of 123I-MIBG ( r=0.95, p<0.01). 3D 11C-HED PET also yielded well correlated myocardial RI with H / M ratio of MIBG ( r=0.74, p<0.05). 3D 11C-HED PET dedicated higher Va values (0.42±0.04), which estimated spillover from LV into myocardial ROI, than 2D 11C-HED PET (0.34±0.10) ( p<0.01). Conclusions We developed a new method to estimate myocardial sympathetic nerve function using 3D PET with 11C-HED, which yielded well suppressed spillover fraction into myocardium using a non-uniform weighted least squared fitting