Ahmed Abdella M, Tashima Hideaki, Yamaya Taiga
National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
Radiol Phys Technol. 2018 Mar;11(1):7-12. doi: 10.1007/s12194-017-0425-2. Epub 2017 Oct 6.
The dominant factor limiting the intrinsic spatial resolution of a positron emission tomography (PET) system is the size of the crystal elements in the detector. To increase sensitivity and achieve high spatial resolution, it is essential to use advanced depth-of-interaction (DOI) detectors and arrange them close to the subject. The DOI detectors help maintain high spatial resolution by mitigating the parallax error caused by the thickness of the scintillator near the peripheral regions of the field-of-view. As an optimal geometry for a brain PET scanner, with high sensitivity and spatial resolution, we proposed and developed the helmet-chin PET scanner using 54 four-layered DOI detectors consisting of a 16 × 16 × 4 array of GSOZ scintillator crystals with dimensions of 2.8 × 2.8 × 7.5 mm. All the detectors used in the helmet-chin PET scanner had the same spatial resolution. In this study, we conducted a feasibility study of a new add-on detector arrangement for the helmet PET scanner by replacing the chin detector with a segmented crystal cube, having high spatial resolution in all directions, which can be placed inside the mouth. The crystal cube (which we have named the mouth-insert detector) has an array of 20 × 20 × 20 LYSO crystal segments with dimensions of 1 × 1 × 1 mm. Thus, the scanner is formed by the combination of the helmet and mouth-insert detectors, and is referred to as the helmet-mouth-insert PET scanner. The results show that the helmet-mouth-insert PET scanner has comparable sensitivity and improved spatial resolution near the center of the hemisphere, compared to the helmet-chin PET scanner.
限制正电子发射断层扫描（PET）系统固有空间分辨率的主要因素是探测器中晶体元件的尺寸。为了提高灵敏度并实现高空间分辨率，使用先进的深度交互（DOI）探测器并将它们靠近受试者放置至关重要。DOI探测器通过减轻视野周边区域附近闪烁体厚度引起的视差误差，有助于保持高空间分辨率。作为具有高灵敏度和空间分辨率的脑PET扫描仪的最佳几何结构，我们提出并开发了头盔 - 下巴PET扫描仪，它使用54个四层DOI探测器，由尺寸为2.8×2.8×7.5 mm的GSOZ闪烁体晶体的16×16×4阵列组成。头盔 - 下巴PET扫描仪中使用的所有探测器具有相同的空间分辨率。在本研究中，我们通过用可放置在口腔内的、在所有方向上具有高空间分辨率的分段晶体立方体替换下巴探测器，对头盔PET扫描仪的新型附加探测器布置进行了可行性研究。该晶体立方体（我们将其命名为口腔插入探测器）具有20×20×20个尺寸为1×1×1 mm的LYSO晶体段阵列。因此，扫描仪由头盔和口腔插入探测器组合而成，被称为头盔 - 口腔插入PET扫描仪。结果表明，与头盔 - 下巴PET扫描仪相比，头盔 - 口腔插入PET扫描仪在半球中心附近具有相当的灵敏度和更高的空间分辨率。
