title: Novel laser-processed CsI:Tl detector for SPECT.
abstract: OBJECTIVE
  The aim of this work is to demonstrate the feasibility of a novel technique for fabrication of high spatial resolution CsI:Tl scintillation detectors for single photon emission computed tomography systems.
  
  
  METHODS
  The scintillators are fabricated using laser-induced optical barriers technique to create optical microstructures (or optical barriers) inside the CsI:Tl crystal bulk. The laser-processed CsI:Tl crystals are 3, 5, and 10 mm in thickness. In this work, the authors focus on the simplest pattern of optical barriers in that the barriers are created in the crystal bulk to form pixel-like patterns resembling mechanically pixelated scintillators. The monolithic CsI:Tl scintillator samples are fabricated with optical barrier patterns with 1.0 × 1.0 mm(2) and 0.625 × 0.625 mm(2) pixels. Experiments were conducted to characterize the fabricated arrays in terms of pixel separation and energy resolution. A 4 × 4 array of multipixel photon counter was used to collect the scintillation light in all the experiments.
  
  
  RESULTS
  The process yield for fabricating the CsI:Tl arrays is 100% with processing time under 50 min. From the flood maps of the fabricated detectors exposed to 122 keV gammas, peak-to-valley (P/V) ratios of greater than 2.3 are calculated. The P/V values suggest that regardless of the crystal thickness, the pixels can be resolved.
  
  
  CONCLUSIONS
  The results suggest that optical barriers can be considered as a robust alternative to mechanically pixelated arrays and can provide high spatial resolution while maintaining the sensitivity in a high-throughput and cost-effective manner.
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129.
authors.forename: H
authors.initials: H
authors.lastname: Sabet
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129 and Department of Physics and Astronomy, Uppsala University, Uppsala 75120, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Bläckberg
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129.
authors.forename: D
authors.initials: D
authors.lastname: Uzun-Ozsahin
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129.
authors.forename: G
authors.initials: G
authors.lastname: El-Fakhri
mesh_terms: D004867:Equipment Design; D005240:Feasibility Studies; D007834:Lasers; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation*