title: A high resolution, monolithic crystal, PET/MRI detector with DOI positioning capability.
abstract: We report on a high resolution, monolithic crystal PET detector design that provides depth of interaction (DOI) positioning within the crystal and is compatible for operation in a MRI scanner to support multimodal anatomic and functional imaging. Our design utilizes a novel sensor on the entrance surface (SES) design combined with a maximum likelihood positioning algorithm. The sensor will be a two-dimensional array of micro-pixel avalanche photodiodes (MAPD). MAPDs are a new type of solid-state photodetector with Geiger mode operation that can provide signal gain similar to a photomltipiler tube (PMT). In addition, they can be operated in high magnetic fields to support PET/MR imaging. Utilizing a multi-step simulation process, we determined the intrinsic spatial resolution characteristics of a detector using the proposed design. For a 48.8 mm by 48.8 mm by 15 mm LSO crystal detector readout by an 8 by 8 array of 5.8 mm by 5.8 mm MAPD elements the intrinsic spatial resolution is 0.83 mm FWHM in X, 0.92 mm FWHM in Y and 1.83 mm FWHM in Z (i.e., DOI) for normally incident photons. Comparing the results versus using a conventional design with the photosensors on the backside of the crystal, an average improvement of 25% in X, 23% in Y, and 20% in Z is achieved.
authors.affiliation: University of Washington, Department of Physics, Seattle, USA. lixioli@u.washington.edu
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Li
authors.forename: Cate
authors.initials: C
authors.lastname: Lockhart
authors.forename: Tom K
authors.initials: TK
authors.lastname: Lewellen
authors.forename: Robert S
authors.initials: RS
authors.lastname: Miyaoka
mesh_terms: D000465:Algorithms; D004867:Equipment Design / Q000295:instrumentation; D016013:Likelihood Functions; D008187:Lutetium; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D017640:Silicates
chemical_list: D017640:Silicates; C477682:lutetium orthosilicate; D008187:Lutetium