Nucleus-Nucleus 2015, Catania,  Motivation: need for accurate ion beam range verification in hadron therapy  Method: prompt-  imaging via Compton scattering kinematics R&D on Compton camera (with electron tracking capability)  Design, setup and characterization of prototype detector system P.G. Thirolf, LMU Munich p, C A Compton Camera Prototype for Prompt Gamma Medical Imaging

Nucleus-Nucleus 2015, Catania, Prompt gamma emission from proton beam on biomedical sample  irradiation of water phantom with 100 MeV protons: 4.4 MeV 12 C 5.2 MeV 15 N, 15 O 6.1 MeV 16 O Counts / GeV/ incident p 50 cm Ø 10 cm p H2OH2O Energy [MeV]  key issue in hadron therapy: - localization of Bragg peak within patient/sample  range verification of therapeutic proton (or ion) beam (simulation)  experimental approach: imaging via prompt  emission from nuclear reactions

Nucleus-Nucleus 2015, Catania, (Prompt) Gamma Imaging: Compton Camera  exploit kinematics of Compton scattering: (i)  tracking: -

Nucleus-Nucleus 2015, Catania, (Prompt) Gamma Imaging: Compton Camera (ii ) electron tracking: advantage: - reconstruction of incompletely absorbed events  increased reconstruction efficiency E  ≥ 1-2 MeV

Nucleus-Nucleus 2015, Catania, Garching Compton Camera Prototype C. Lang et al., JINST 9 (2014) P01008, PhD thesis (LMU, 2015) 10 mm each Scatterer/Tracker Absorber 50 mm 85 mm E  : MeV e-e-   Compton camera layout:

Nucleus-Nucleus 2015, Catania, Compton Camera Prototype: Scatter/Tracker Array 6  Scatterer/Tracker Array: 6x double-sided silicon strip detectors (DSSSD)  active area 50 x 50 mm 2  thickness : 500  m  128 strips on each side  pitch size 390  m Saad Aldawood (KSU/LMU), PhD thesis, in preparation  DSSSD readout: Gassiplex (4x16 ch. ASIC):  charge-sensitive preamplifier  shaper  digital discriminator  track & hold-stage  multiplexed ADC Adapter board DSSSD Gassi- plex (64 ch.) Gassi- plex AC Wafer ACAC ACAC 2x 64 strips/ side VME readout controller

Nucleus-Nucleus 2015, Catania, Compton Camera Prototype 7 S. Aldawood, PhD thesis, in preparation - light tight enclosure - Faraday cage (+ ventilation, thermal control) scatterer/tracker array Compton camera prototype:

Nucleus-Nucleus 2015, Catania, Compton Camera Prototype 8  Absorber: LaBr 3 crystal: 50 x 50 x 30 mm 3. PMT: Hamamatsu H9500 (multi-anode: 16x16):.  signal processing: pixel (3x3 mm 2 ) - individual spectroscopy electronics channels for E, t S. Aldawood, PhD thesis, in preparation LaBr 3 PMT 256 ch. LaBr 3 PMT  fast amplifier + CFD (Mesytec MCFD-16, 16 ch.)  energy: charge-sensitive digital converter (Mesytec, 32 ch. VME-QDC)  time: (multi-hit) TDC (Mesytec, 32 ch. VME)

Nucleus-Nucleus 2015, Catania, LaBr 3 detector properties: energy / time resolution Pixel (x) Pixel (y)  energy resolution: = 662 keV ( 137 Cs)  time resolution:  t ~ 270 ps Time[ns] Energy [keV] Time[ns] Counts/0.1 ns - E d =20 MeV (pulsed) - water phantom - s=0.5 m:  t=12 ns  n  n H. v.d. Kolff, Master thesis, TU Delft/LMU (2014) 60 Co source:

Nucleus-Nucleus 2015, Catania, High-Energy Calibration 10  Experiment at Tandetron (HZDR, Dresden/Rossendorf): - low energy (~1 MeV) protons - E  = 4.44 MeV via 15 N(p,  ) 12 C sim.: GEANT MeV3.93 MeV3.42 MeV  validation of MC simulations counts / keV energy / keV 4.44 MeV 3.93 MeV3.42 MeV exp S. Aldawood, PhD thesis, in preparation

Nucleus-Nucleus 2015, Catania, Scatter/Tracker Array 11  energy deposition in 6 DSSSD layers: E  = 4.4 MeV - from simulation: increasing yield from front- to backside layers (accumulating contributions from Compton electrons) GEANT 4 layer 1 layer E  [keV] counts/ keV  simulations verified E  [ch.] counts/ ch. Exp. layer 6 layer S. Aldawood, PhD thesis, in preparation

Nucleus-Nucleus 2015, Catania, Commissioning at Garching Tandem Accelerator 12 p beam H 2 O phantom E  [keV] Counts / 8 keV 16 O* 4.44 MeV 5.11 MeV (6.130 – 0.511) ( – 1.022) (4.440 – 0.511) (4.440 – 1.022) 6.13 MeV 14 N* 12 C*  20 MeV protons + water phantom: prompt-  spectrum I. Castelhano, Master thesis, U Lisbon/LMU, 2014 sim.: GEANT 4

Nucleus-Nucleus 2015, Catania, LaBr 3 detector properties: Spatial resolution H. v.d. Kolff, Master thesis, TU Delft/LMU (2014)  spatial resolution: - collimated  source (Ø 1 mm): 137 Cs (662 keV, ca. 80 MBq)  2D scan of LaBr 3  data analysis: - background correction - gain matching/uniformity correction: electronics, PMT  “k-nearest neighbour” algorithm (TU Delft)  derive position information from monolithic crystal 137Cs137Cs automated positioning stage Pb shield 137 Cs LaBr 3 PMT collimator H.T. van Dam et al., IEEE TNS 58 (2011) 2139

Nucleus-Nucleus 2015, Catania, Spatial Resolution from Monolithic Scintillator: “kNN-Algorithm” H.T. van Dam et al., IEEE TNS 58 (2011) 2139

Nucleus-Nucleus 2015, Catania, LaBr 3 detector properties: Spatial resolution S. Aldawood, PhD thesis, LMU, in preparation - 2D scan with collimated 137 Cs source - irradiation of 16x16 pixels (3x3 mm 2 )  light amplitude distribution maps: - goal: 10 4 maps as reference data set (0.5 mm collimation, 0.5 mm step size) T. Marinšek, Master thesis, LMU, in preparation - irradiation of 102 x102 positions (grid: 0.5 mm) - 50 events/ position; k=2000:  kNN method (1 mm collimator) kNN position reconstruction

Nucleus-Nucleus 2015, Catania, Commissioning at Clinical Proton Beam Facility  OncoRay (Dresden): National Center for Radiation Research in Oncology cyclotron, f RF = 106 MHz   t = 9.4 ns tissue-equivalent targets: - water phantom - PMMA ( Polymethylmethacrylat ) proton penetration depth in water: E p = 225 MeV : ~ 32 cm (very recent data from June 1-5)

Nucleus-Nucleus 2015, Catania, Prompt  spectra PMMA target E p =100 MeV E p =160 MeV E p =225 MeV 12 C* water target E p =100 MeV E p =160 MeV E p =225 MeV 16 O* 12 C*

Nucleus-Nucleus 2015, Catania, Commissioning at Clinical Proton Beam  Strip detectors: layer 6 layer  Compton electron energy deposition: here: p-sides, each 64 odd strips 225 MeV, water target Si 1 Si 2 Si 3 Si 4 Si 5 Si 6 S. Liprandi, PhD thesis (in preparation)

Nucleus-Nucleus 2015, Catania, Summary  exploiting full potential of hadron therapy: - requires (online) verification of ion beam stopping range - Compton camera provides (prompt-  ) imaging capabilities - development of prototype with electron tracking capability ongoing - absorber: LaBr 3 scintillator - scatterer/tracker: array of double-sided Si-strip detectors  prompt-gamma range monitoring:  prototype characterization: - offline: energy and time resolution, photopeak efficiency - online: 4.4 MeV photons 20 MeV protons (Tandem) 100/160/225 MeV protons (clinical cyclotron) - ongoing: position determination in monolithic scintillator  next steps: - source position image reconstruction

Nucleus-Nucleus 2015, Catania, Thanks to … Thank you for your attention !  LMU Munich: C. Lang, S. Aldawood, I. Castelhano, H. v.d. Kolff, S. Liprandi, T. Marinsek, M. Pocevicius, B. Tegetmeyer, G. Dedes, R. Lutter, J. Bortfeldt, K. Parodi  TU Munich: L. Maier, M. Böhmer, R. Gernhäuser  TU Delft: D.R. Schaart  OncoRay/ HZDR, Dresden: G. Pausch, C. Golnik, F. Hueso-Gonzalez, T. Kormoll, K. Römer, J. Petzoldt, F. Fiedler Supported by DFG Cluster of Excellence MAP (Munich-Centre for Advanced Photonics)

Nucleus-Nucleus 2015, Catania,  simulations for tracker/absorber specifications and expected performance: n DSSSD =6 full absorption  tracking ; source - tracker: 50 mm 64 pixel (6x6mm 2 ) 256 pixel (3x3mm 2 ) absorber: 300  m Si 500  m Si 300  m Si 500  m Si  + e tracking, 500  m  + e tracking, 300  m  tracking, 500  m  tracking, 300  m   +e Compton Camera Design Simulations - 6x6 mm 2  3x3 mm 2 pixel: - spatial resolution improves by ≥50 % - d=500  m + electron tracking:  improved efficiency -  ≈ – MeV for optimum resolution) - angular resolution ≈ 2 o – 2.5 o 2-6 MeV)