High‐resolution x‐ray imaging using a structured scintillator. Issue 2 (13th January 2016)

• Record Type: Journal Article
• Authors: Hormozan, Yashar; Sychugov, Ilya; Linnros, Jan
• Is Part Of: Medical physics. Volume 43:Issue 2(2016)
• Page Start: 696
• Page End: 701
• Publication Date: 2016-01-13
• Subjects: CCD image sensors -- computerised tomography -- diagnostic radiography -- image resolution -- mammography -- optical transfer function -- scintillation counters; Radiography -- Mammography -- Mammography -- Computed tomography; Computerised tomographs -- Biological material, e.g. blood, urine; Haemocytometers -- Charge coupled imagers; structured scintillator -- modulation transfer function (MTF) -- caesium iodide (CsI) -- detector -- x‐ray -- microscope; X‐ray imaging -- Scintillation detectors -- Charge coupled devices -- Medical X‐ray imaging -- Modulation transfer functions -- X‐ray detectors -- Photons -- X‐ray absorption near edge structure; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4939258
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: In this study, the authors introduce a new generation of finely structured scintillators with a very high spatial resolution (a few micrometers) compared to conventional scintillators, yet maintaining a thick absorbing layer for improved detectivity. Methods: Their concept is based on a 2D array of high aspect ratio pores which are fabricated by ICP etching, with spacings (pitches) of a few micrometers, on silicon and oxidation of the pore walls. The pores were subsequently filled by melting of powdered CsI(Tl), as the scintillating agent. In order to couple the secondary emitted photons of the back of the scintillator array to a CCD device, having a larger pixel size than the pore pitch, an open optical microscope with adjustable magnification was designed and implemented. By imaging a sharp edge, the authors were able to calculate the modulation transfer function (MTF) of this finely structured scintillator. Results: The x‐ray images of individually resolved pores suggest that they have been almost uniformly filled, and the MTF measurements show the feasibility of a few microns spatial resolution imaging, as set by the scintillator pore size. Compared to existing techniques utilizing CsI needles as a structured scintillator, their results imply an almost sevenfold improvement in resolution. Finally, high resolution images, taken by their detector, are presented. Conclusions: The presented work successfully shows the functionality of their detector concept for high resolution imaging and further fabrication developments are most likely to result in higher quantum efficiencies.