2. Fastest Data Processing in Image Reconstruction for Compton Camera Imaging
DTSP-Workshop on “Ultra-fast data transfer and reconstruction” (pillar 2) 
Burg Obbendorf, Jülich
 May 9th - May 10th
Sebastian Schöne, Radiation Physics, HZDR

3. About us – HZDR – Helmholtz-Zentrum Dresden-Rossendorf
Helmholtz-Institut Freiberg
HZDR Research Site Leipzig
The Rossendorf Beamline at ESRF, Grenoble, France
maps.google.de

4. About us – HZDR – Helmholtz-Zentrum Dresden-Rossendorf
Joined the Helmholtz association in 2011
More than 800 employees
Research in the sectors health, energy, and matter
Research facilities
Superconducting electron accelerator ELBE as a source of high brilliance and low emittance for the production of Bremsstrahlung, neutrons, infrared FEL-radiation
High Magnetic Field Laboratory HLD to generate highest pulsed magnetic fields
Ion Beam Center for Materials Research …
Involved in international experiments at the ESRF, GSI, FAIR
Medical research
PET center in radiopharmacy, therapy and medical imaging
OncoRay – National Center for Radiation Research in Oncology
DKTK

5. Cross cutting activities
Objectives within the project – CCI Image Reconstruction
Ultrafast data
transfer and
reconstruction
Intelligent programmable
hardware
Near detector
optical signal
transmission
Fastest data
processing with
highly parallel
architectures
Technologies for
assembling highly
integrated detectors
3D ASICs
Mixed-signal ASICs
3D / high-Z sensors
Packaging and interconnection technologies
Innovative detector structure materials
Detector types
Fast photon and
X-ray detectors
Diamond detectors
Detectors for
thermal neutrons
Compact gas detectors
Cross cutting activities

6. Why Compton camera imaging (CCI) ?
Objectives within the project – CCI Image Reconstruction
Why Compton camera imaging (CCI) ?
Tumor radiation therapy
Protons (and light ions)
More local dose deposition w.r.t. photon irradiation
Dose monitoring
Prompt gammas
SPECT
By means of Compton cameras
A. Müller, Geant4 simulations

7. Principle of Compton camera imaging
Objectives within the project – CCI Image Reconstruction
Principle of Compton camera imaging
Q, Eg
P, L1
R, L2 q
scatter P
absorber g
Scatter
Absorber
apex
axis R

8. Objectives within the project – CCI Image Reconstruction
Our prototypes
C. Golnik, CZT-CZT-Setup
T. Kormoll, CZT-LSO-Setup

9. Objectives within the project – CCI Image Reconstruction
Imaging workflow
Study object x
Measurement y = A(x)
Measurement series y
Reconstruction x’ = A-1(y)
Reconstructed image x’ ≈ x
1st Construct model A of device
2nd Optimize image x’

10. 1st Construct model A of device
Objectives within the project – CCI Image Reconstruction
1st Construct model A of device +
y=A(x) high dimensional: y \in R8, x \in R4
Measured data handled as distributions
Additional influences
Cross sections
Camera geometry ….
Medium memory consuming
High time consumption
~1 s/event/core
Assumption: 10k events/s
Assumption: 100k filtered events per recording 

11. Objectives within the project – CCI Image Reconstruction
2nd Optimize image x’
22Na (0,4,7) cm
Eventfilter 1275 keV +/- 20%
Standard algorithms exist
Less complex
Less time consuming
High memory consumption
e.g. operate on n*10G floats
Summed backprojection
1,2,…,7,50,100,500,800 events
MLEM, Iteration 1, 2 … 25
800 events

12. Status quo Plans Wishes
Objectives within the project – CCI Image Reconstruction
Status quo
Plans
Wishes
Python
NumPy + SciPy
Workstation & HPC cluster
Migration to massive parallel programming
Selective (module)
Successive
Permanent Parallel drop-in replacement ? (beam time, treatment room)
Interface to high-level programming
Python integration
OpenCL vs. CUDA
Multi-GPGPU
GPGPU-alternatives ….
Are ‘general purpose’ implementations reasonable?

13. HPC @ HZDR HPC @ TU Dresden
Objectives within the project – CCI Image Reconstruction
HZDR
TU Dresden
2 HPC clusters
Small GPGPU cluster
S1070
C2070
Multiple HPC cluster
GPGPU cluster
S1070
S2050
C2070 …
Lectures on massive parallel programming
CUDA Research Center
Awarded CUDA Center of Excellence