A prototype of time-of-flight positron emission computed tomography(TOF-PET) has been developed for acquiring the coincident detection of 511 keV γ-rays produced from positron annihilation.It consists of two 80.5 mm&...A prototype of time-of-flight positron emission computed tomography(TOF-PET) has been developed for acquiring the coincident detection of 511 keV γ-rays produced from positron annihilation.It consists of two 80.5 mm×80.5 mm LYSO scintillator arrays(composed of 35 ×35 pixel finger crystals) with the position sensitive photomultiplier tubes R2487 as the readout.Each array is composed of 2 mm ×2 mm×15 mm finger crystals and the average pixel pitch is 2.30 mm.The measured results indicate that the TOF information has the potential to significantly enhance the image quality by improving the noise variance in the image reconstruction.The best spatial resolution(FWHM) of the prototype for the pairs of 511 keV γ-rays is 1.98 mm and 2.16 mm in the x and y directions,respectively,which are smaller than the average pixel pitch of 2.30 mm.展开更多
This study was to assess quantitatively the accuracy of ^(18)F-FDG PET/CT images reconstructed by TOF+PSF and TOF only, considering the noise-matching concept to minimize probable bias in evaluating algorithm performa...This study was to assess quantitatively the accuracy of ^(18)F-FDG PET/CT images reconstructed by TOF+PSF and TOF only, considering the noise-matching concept to minimize probable bias in evaluating algorithm performance caused by noise. PET images of similar noise level were considered. Measurements were made on an inhouse phantom with hot inserts of Φ10–37 mm, and oncological images of 14 patients were analyzed. The PET images were reconstructed using the OSEM, OSEM+TOF and OSEM+TOF+PSF algorithms. Optimal reconstruction parameters including iteration, subset, and FWHM of post-smoothing filter were chosen for both the phantom and patient data. In terms of quantitative accuracy, the recovery coefficient(RC) was calculated for the phantom PET images. The signal-to-noise ratio(SNR),lesion-to-background ratio(LBR), and SUV_(max)were evaluated from the phantom and clinical data. The smallest hot insert(Ф10 mm) with 2:1 activity concentration ratio could be detected in the PET image reconstructed using the TOF and TOF+PSF algorithms, but not the OSEM algorithm. The relative difference for SNR between the TOF+PSF and OSEM showed significantly higher values for smaller sizes, while SNR change was smaller for Ф22–37 mm inserts both 2:1 and 4:1 activity concentration ratio. In the clinical study, SNR gains were 1.6 ± 0.53 and 2.7 ± 0.74 for the TOF and TOF+PSF, while the relative difference of contrast was 17 ± 1.05 and 41.5 ± 1.85% for the TOF only and TOF+PSF, respectively. The impact of TOF+PSF is more significant than that of TOF reconstruction, in smaller inserts with low activity concentration ratio. In the clinical PET/CT images, the use of the TOF+PSF algorithm resulted in better SNR and contrast for lesions, and the highest SUV_(max)was also seen for images reconstructed with the TOF+PSF algorithm.展开更多
简要介绍了基于飞行时间(Time of Flight,简称TOF)技术的正电子发射断层扫描成像(Posi-tron Emission Tomography,简称PET)的基本原理,回顾了TOF-PET成像设备的发展历史,讨论了影响TOF-PET时间分辨率的主要因素,并对TOF-PET给图像重建...简要介绍了基于飞行时间(Time of Flight,简称TOF)技术的正电子发射断层扫描成像(Posi-tron Emission Tomography,简称PET)的基本原理,回顾了TOF-PET成像设备的发展历史,讨论了影响TOF-PET时间分辨率的主要因素,并对TOF-PET给图像重建技术带来的挑战进行了分析。最后,重点介绍了TOF-PET技术所带来的优势,使用TOF技术可以有效地改善图像质量,并且为临床诊断和临床前研究带来便利。展开更多
基金Supported by National Natural Science Foundation of China (10305015,10475098)West Light Foundation of Chinese Academy of Sciences(0801010XBB)Major Foundation Program of Chinese Academy of Sciences(O701050YZD)
文摘A prototype of time-of-flight positron emission computed tomography(TOF-PET) has been developed for acquiring the coincident detection of 511 keV γ-rays produced from positron annihilation.It consists of two 80.5 mm×80.5 mm LYSO scintillator arrays(composed of 35 ×35 pixel finger crystals) with the position sensitive photomultiplier tubes R2487 as the readout.Each array is composed of 2 mm ×2 mm×15 mm finger crystals and the average pixel pitch is 2.30 mm.The measured results indicate that the TOF information has the potential to significantly enhance the image quality by improving the noise variance in the image reconstruction.The best spatial resolution(FWHM) of the prototype for the pairs of 511 keV γ-rays is 1.98 mm and 2.16 mm in the x and y directions,respectively,which are smaller than the average pixel pitch of 2.30 mm.
基金supported by the Tehran University of Medical Sciences,Tehran,Iran(No.24166)the Masih Daneshvari Hospital,Shahid Beheshti University of Medical Sciences,Tehran,Iran
文摘This study was to assess quantitatively the accuracy of ^(18)F-FDG PET/CT images reconstructed by TOF+PSF and TOF only, considering the noise-matching concept to minimize probable bias in evaluating algorithm performance caused by noise. PET images of similar noise level were considered. Measurements were made on an inhouse phantom with hot inserts of Φ10–37 mm, and oncological images of 14 patients were analyzed. The PET images were reconstructed using the OSEM, OSEM+TOF and OSEM+TOF+PSF algorithms. Optimal reconstruction parameters including iteration, subset, and FWHM of post-smoothing filter were chosen for both the phantom and patient data. In terms of quantitative accuracy, the recovery coefficient(RC) was calculated for the phantom PET images. The signal-to-noise ratio(SNR),lesion-to-background ratio(LBR), and SUV_(max)were evaluated from the phantom and clinical data. The smallest hot insert(Ф10 mm) with 2:1 activity concentration ratio could be detected in the PET image reconstructed using the TOF and TOF+PSF algorithms, but not the OSEM algorithm. The relative difference for SNR between the TOF+PSF and OSEM showed significantly higher values for smaller sizes, while SNR change was smaller for Ф22–37 mm inserts both 2:1 and 4:1 activity concentration ratio. In the clinical study, SNR gains were 1.6 ± 0.53 and 2.7 ± 0.74 for the TOF and TOF+PSF, while the relative difference of contrast was 17 ± 1.05 and 41.5 ± 1.85% for the TOF only and TOF+PSF, respectively. The impact of TOF+PSF is more significant than that of TOF reconstruction, in smaller inserts with low activity concentration ratio. In the clinical PET/CT images, the use of the TOF+PSF algorithm resulted in better SNR and contrast for lesions, and the highest SUV_(max)was also seen for images reconstructed with the TOF+PSF algorithm.
文摘简要介绍了基于飞行时间(Time of Flight,简称TOF)技术的正电子发射断层扫描成像(Posi-tron Emission Tomography,简称PET)的基本原理,回顾了TOF-PET成像设备的发展历史,讨论了影响TOF-PET时间分辨率的主要因素,并对TOF-PET给图像重建技术带来的挑战进行了分析。最后,重点介绍了TOF-PET技术所带来的优势,使用TOF技术可以有效地改善图像质量,并且为临床诊断和临床前研究带来便利。
