Speaker
Description
Propagation-based phase-contrast X-ray imaging (PB-PCXI) is a technique suitable for imaging weakly-attenuating objects, e.g., biological samples, as it utilizes both attenuation and refraction effects. Such effects are material dependent, and described by the X-ray’s complex refractive index n=1-δ+iβ, where β and δ describe attenuation, and refraction, respectively. Phase retrieval algorithms are typically applied to PB-PCXI images to recover lost phase information. A single-material reconstruction, based on the transport-of-intensity equation, has been published by Paganin et al. [1] and has proven useful in diverse fields. This approach has been extended to consider multi-material objects [2], and partially-coherent X-ray sources [3]. The described phase-retrieval algorithms can successfully recover the projected-phase information of an object, however, they require a priori knowledge of the sample materials. We present an algorithm capable of extracting β and δ functions for a sample that is composed of unknown materials. The essence of the approach is based on curve-fitting an error-function to each interface between distinct materials in a computed tomographic reconstruction [4], where the fit parameters are then used to calculate δ and β for composite materials. This approach requires no a priori sample information, making it broadly applicable, particularly in cases where exact sample composition is unknown. We have applied this method to a breast-tissue sample, where the δ for composite materials was calculated to 0.6% - 2.5% accuracy, compared to theoretical values.
- D. M. Paganin et al., J.Microsc. 206, 33 (2002)
- M. A. Beltran et al., Opt.Express 18, 6423 (2010)
- M. A. Beltran et al., J.Opt. 20, 055605 (2018)
- D. A. Thompson et al., J.Synchrotron.Radiat. 26, 825-838 (2019)
| Level of Expertise | Student |
|---|---|
| Students Only - Are you interested in AINSE student funding | Yes |
| Which facility did you use for your research | Australian Synchrotron |
| Pronouns | She/Her |
| Presenter Gender | Woman |
| Condition of submission | Yes |
| Do you wish to take part in the Student Poster Slam | Yes |
