X- ray imaging. F. Grüner

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Owen Haynes
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1 X- ray imaging F. Grüner

2 Röntgen s first medical imaging

3 Improvements. System-specific image processing Adaptive auto-windowing algorithm

4 Basic principles X- ray absorp1on/phase contrast imaging X- ray fluorescence contrast signal ( tumor is light source )

$contrast imaging refracave index is wriaen as n = 1 d + iß phase contrast$

5 d and ß as a func1on of energy in kev for biological 1ssue absorpaon vs phase contrast imaging refracave index is wriaen as n = 1 d + iß phase contrast absorp1on

6 absorpaon vs phase contrast imaging different contrast generaaon absorp1on phase contrast hap://

phase contrast hap://www.medphys.ucl.ac.

7 absorpaon vs phase contrast imaging different contrast quality absorp1on phase contrast hap://

8 absorpaon imaging: simulaaons high resolu1on voxel models of breast created from CT- scans of anatomical breast specimens voxel size: 60 x 60 x 60 µm³ segmenta1on in different 1ssues: - adipose - glandular - skin using brilliant undulator radia1on: beam geometry, spectral angular flux,... simula1on of absorp1on and scaaering processes with Geant4- SoXware- Toolkit

9 absorpaon imaging: contrast reducaon Balance in imaging processing Object detail Surrounding structures

10 absorpaon imaging: contrast reducaon 0.2 mgy average glandular dose at ~10¹¹ photons primary Rayleigh Compton

11 absorpaon imaging: contrast enhancement Rasterfocus (focal spot) Primary radiation geometrical limitation of radiation (aperture) anti-scatter grid ideal: focused anti-scatter grid Object Scattered rad. X ray film layer Raster Absorber Blade Anti-Scatter grid is placed directly on the film /screenfilm-system / detector

12 absorpaon imaging: applied dose a) Frequency of examinations b) Collective effective dose from medicine

13 absorpaon imaging: applied dose criterion = signal- difference- to- noise ra1o versus averaged- glandular dose analy1cal model simulaaon for 3 different breast models requires tunable source

14 absorpaon imaging: applied dose minimum is always at ca. 20% transmission through main absorber Together with MAP-AG Florian Gruener Typically used number of photons in clinical systems number of photons (n) / % 10% 20% 30% 40% 50% 60% 70% k=693 Transmission of Main Absorber p Together with Felix Schöfer, Schöfer et al. in prep.

15 dual energy Actual: dual energy CT with contrast media for e.g. lung perfusion è New diagnostic tool è at least two scans è high dose è registration problems è non-optimal image information due to overlapping spectra è Limitations for suitable markers Lung perfusion dual energy CT, courtesy of LMU With especially designed monoenergetic radiation low dose individualised medicine will be developed together with MAP II

16 dual energy

coherent scaier imaging - Differen1a1on between 1ssue structures - most notably between malign and benign carcinomas by different scaaer intensity caused by change in the collagen

17 coherent scaier imaging - Differen1a1on between 1ssue structures - most notably between malign and benign carcinomas by different scaaer intensity caused by change in the collagen structure of malign 1ssue different scaaer distribu1on è DifferenAaAon between malign and benign Assue without the need for biopsy would be a great benefit Image of scatter distribution in tumour

18 X- ray fluorescence imaging e.g. 100 kev incident, 69 kev Au line

19 fluorescence imaging: experiments

20 fluorescence imaging: experiments sinogram

21 (simulation by B. Müller, HZM/MAP) fluorescence imaging: background fluorescence Compton input energy max. sensitivity at 1mGy / 5mm pixel / CNR=5 ~ 10µg/ml ~ 100 times more sensitive than transmission-ct

22 Physicists impacts new methods: phase- contrast with low- brillance sources absorp1on/x- ray fluorescence with high- brillance sources pushing the limits: dose reduc1on lowering the concentra1on of contrast media enhancing the sensi1vity enforcing persoanlized medicine cooperaaons between medicine and physics: possibly compara1ve studies between UKE and my group (magne1c par1cle imaging vs X- ray fluorescence imaging new detectors for medicine (Erika!!)

Eﬀect of non- homogeneous breast 3ssue on mean glandular dose assessment in digital breast tomosynthesis

Eﬀect of non- homogeneous breast 3ssue on mean glandular dose assessment in digital breast tomosynthesis Eﬀect of nonhomogeneous breast 3ssue on mean glandular dose assessment in digital breast tomosynthesis M. Bap3sta, S. Di Maria, C. Figueira, L. Orvalho, A. Silva, P. Vaz, M. Zankl o Mo3va3on Mammography