A Multi-Purpose Clinical PET Scanner with Dynamic Gantry Design

Abstract

Conventional PET scanners provide sufficient axial field-of-view (FOV) for whole-body imaging with moderate spatial resolution. Conversely, dedicated organ-specific (brain, breast, prostate) PET scanners were designed to provide high-spatial resolution though they commonly have a small FOV. A versatile multi-purpose PET scanner capable of serving as a conventional and dedicated brain PET scanner would be highly appealing in the clinical setting. In this light, the dynamic gantry PET scanner combining conventional and dedicated brain PET scanners into a single gantry is introduced. The proposed PET scanner geometry, referred to as the dynamic gantry, is based on the Siemens mCT Biograph PET scanner, wherein half of the detector blocks are made of pixelated crystals with a crystal width of 4 mm and crystal depth of 2 cm (referred to as high-sensitivity blocks). The second half is made of crystals with a width of 2 mm and a depth of 1 cm (referred to as high-resolution blocks). Each detector block set could translate along the radial direction through the actuators to create two large and small transaxial FOVs. The dynamic gantry design could operate in three acquisition modes. The conventional model has the same bore size (78 cm) as the mCT scanner. A small-bore (39 cm) with high-sensitivity (when the high-sensitivity blocks move toward the center of the FOV) and a small bore with high resolution. The scanner could be reconfigured to high-resolution mode to acquire PET images with approximately 2.3 mm spatial resolution compared to the mCT scanner with a spatial resolution of 3.8 mm. In the high-sensitivity mode, the sensitivity of the scanner would be approximately twice as much as that of the mCT Biograph scanner (15.98 vs 8.78 kcps/MBq)).