• Progress in Medical Physics
• /
• v.22 no.3
• /
• pp.140-147
• /
• 2011

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.1
• /
• pp.10-18
• /
• 2009

Purpose: We investigated quantification of dopaminergic transporter (DAT) and serotonergic transporter (SERT) on $^{123}I$-FP-CIT SPECT for differentiating between multiple systemic atrophy (MSA) and idiopathic Parkinson's disease (IPD). Materials and Methods: N-fluoropropyl-$2{\beta}$-carbomethoxy-$3{\beta}$-4-[$^{123}I$]-iodophenylnortropane SPECT ($^{123}I$-FP-CIT SPECT) was performed in 8 patients with MSA (mean age: $64.0{\pm}4.5yrs$, m:f=6:2), 13 with early IPD (mean age: $65.5{\pm}5.3yrs$, m:f=9:4), and 12 healthy controls (mean age: $63.3{\pm}5.7yrs$, m:f=8:4). Standard regions of interests (ROls) of striatum to evaluate DAT, and hypothalamus and midbrain for SERT were drawn on standard template images and applied to each image taken 4 hours after radiotracer injection. Striatal specific binding for DAT and hypothalamic and midbrain specific binding for SERT were calculated using region/reference ratio based on the transient equilibrium method. Group differences were tested using ANOVA with the postHoc analysis. Results: DAT in the whole striatum and striatal subregions were significantly decreased in both patient groups with MSA and early IPD, compared with healthy control (p<0.05 in all). In early IPD, a significant increase in the uptake ratio in anterior and posterior putamen and a trend of increase in caudate to putamen ratio was observed. In MSA, the decrease of DAT was accompanied with no difference in the striatal uptake pattern compared with healthy controls. Regarding the brain regions where $^{123}I$-FP-CIT binding was predominant by SERT, MSA patients showed a decrease in the binding of $^{123}I$-FP-CIT in the pons compared with controls as well as early IPD patients (MSA: $0.22{\pm}0.1$ healthy controls: $0.33{\pm}0.19$, IPD: $0.29{\pm}0.19$), however, it did not reach the statistical significance. Conclusion: In this study, the differential patterns in the reduction of DAT in the striatum and the reduction of pontine $^{123}I$-FP-CIT binding predominant by SERT could be observed in MSA patients on $^{123}I$-FP-CIT SPECT. We suggest that the quantification of SERT as well as DAT using $^{123}I$-FP-CIT SPECT is helpful to differentiate parkinsonian disorders in early stage.