BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Tomographic X-ray phase and attenuation extraction for a sample co
 mposed of unknown materials
DTSTART;VALUE=DATE-TIME:20211126T000500Z
DTEND;VALUE=DATE-TIME:20211126T002000Z
DTSTAMP;VALUE=DATE-TIME:20260306T092453Z
UID:indico-contribution-4313@events01.synchrotron.org.au
DESCRIPTION:Speakers: Samantha Alloo ()\nPropagation-based phase-contrast 
 X-ray imaging (PB-PCXI) is a technique suitable for imaging weakly-attenua
 ting objects\, e.g.\, biological samples\, as it utilizes both attenuation
  and refraction effects. Such effects are material dependent\, and describ
 ed by the X-ray’s complex refractive index n=1-δ+iβ\, where β and δ 
 describe attenuation\, and refraction\, respectively. Phase retrieval algo
 rithms are typically applied to PB-PCXI images to recover lost phase infor
 mation. A single-material reconstruction\, based on the transport-of-inten
 sity equation\, has been published by Paganin et al. [1] and has proven us
 eful in diverse fields. This approach has been extended to consider multi-
 material objects [2]\, and partially-coherent X-ray sources [3]. The descr
 ibed phase-retrieval algorithms can successfully recover the projected-pha
 se information of an object\, however\, they require a priori knowledge of
  the sample materials. We present an algorithm capable of extracting β an
 d δ functions for a sample that is composed of unknown materials. The ess
 ence of the approach is based on curve-fitting an error-function to each i
 nterface between distinct materials in a computed tomographic reconstructi
 on [4]\, where the fit parameters are then used to calculate δ and β for
  composite materials. This approach requires no a priori sample informatio
 n\, making it broadly applicable\, particularly in cases where exact sampl
 e composition is unknown. We have applied this method to a breast-tissue s
 ample\, where the δ for composite materials was calculated to 0.6% - 2.5%
  accuracy\, compared to theoretical values.\n\n1. D. M. Paganin et al.\, J
 .Microsc. 206\, 33 (2002)\n2. M. A. Beltran et al.\, Opt.Express 18\, 6423
  (2010)\n3. M. A. Beltran et al.\, J.Opt. 20\, 055605 (2018)\n4. D. A. Tho
 mpson et al.\, J.Synchrotron.Radiat. 26\, 825-838 (2019)\n\nhttps://events
 01.synchrotron.org.au/event/146/contributions/4313/
LOCATION:Online
URL:https://events01.synchrotron.org.au/event/146/contributions/4313/
END:VEVENT
END:VCALENDAR