IFIMED status and results of a Compton Telescope for hadron therapy

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IFIMED status and results of a Compton Telescope for hadron therapy, Enrique Muñoz, John Barrio, José Bernabéu, Ane Etxebeste, Carlos Lacasta, Josep F. Oliver, Pablo G. Ortega*, Carles Solaz.

1 IFIMED status and results of a Compton Telescope for hadron therapy, Enrique Muñoz, John Barrio, José Bernabéu, Ane Etxebeste, Carlos Lacasta, Josep F. Oliver, Pablo G. Ortega*, Carles Solaz. Instituto de Física Corpuscular IFIC/IFIMED (CSIC-UV) Valencia, Spain * and CERN, Geneva, Switzerland IRIS group: Image Reconstruction, Instrumentation and Simulations in medical applications. 1

IFIMED Completada la Fase I. Visita de inspección técnica: Abril 2016. Instalación asociada orgánicamente al IFIC.

2 IFIMED Completada la Fase I. Visita de inspección técnica: Abril Instalación asociada orgánicamente al IFIC. Dependencias situadas en el parque científico de la UV. Pendientes de comenzar la Fase II: acelerador de protones. 2

3 IFIMED Fase I: Obra civil. Equipamiento laboratorios de instrumentación para imagen, radiofrecuencia y micropet. Laboratorio radiofrecuencia Laboratorio instrumentación Micro PET 3

Servicios: Usuarios finales (investigación biomédica con ratas y ratones,

4 IFIMED MicroPET/CT: SuperArgus de Sedecal. SCSIE - Servei Central Suport a Investigacio Experimental. Servicios: Usuarios finales (investigación biomédica con ratas y ratones, imagenes TAC). Usuarios investigación: desarrollo de detectores y algoritmos de imagen. Super Argus PET/CT Sample preparation room 4

5 IFIMED Laboratorio de instrumentación: Equipamiento de propósito general (fuentes calibración, cámara climática). Investigación en PET, Cámaras Compton y sondas. 5

Hadron therapy Hadron therapy uses ionizing radiation to treat cancer. It is based on the special properties of heavy charged particles such as protons or light ions.

6 Hadron therapy Hadron therapy uses ionizing radiation to treat cancer. It is based on the special properties of heavy charged particles such as protons or light ions. X-rays protons IMRT X-rays progressively deposit energy as they advance Protons penetrate the tissue with reduced energy deposition as they advance Deposit the maximum energy before stopping, defining a peak also known as Bragg peak Almost no energy deposition beyond the Bragg peak. protons carbons HT presents an improved sparing of normal tissue Monitoring of the dose delivery is also more difficult since the beam is fully absorbed 6

Precise delivery to tumour area => increase of cure rates and reduction of side and long term effects and secondary cancer.

7 Hadron therapy Large benefit over conventional radiation therapies in some cases (ocular tumours, children, organs at risk, radioresistant tumours). Higher relative biological effectiveness (RBE) than photons. Precise delivery to tumour area => increase of cure rates and reduction of side and long term effects and secondary cancer. photons Protons L. Widesott et al. Intensitymodulated proton therapy versus helical tomotherapy in nasopharynx cancer: planning comparison and NTCP evaluation. IJROBP 72(2):589, Oct

Essential: To verify dose delivery and correct for treatment deviations.

8 Treatment monitoring PROBLEM: the dose administered can not be directly measured (as done in conventional radiotherapy). Secondary particles emitted during treatment can be used for monitoring the dose delivery. Essential: To verify dose delivery and correct for treatment deviations. To reduce safety margins and better exploit hadron therapy. Positron Emission Tomography (PET) + MC currently employed. + emission is correlated with the dose. 8

Treatment monitoring Dose verification with PET: Comparison of dose planned and estimated from detected + activity. PET Limitations: Positron production does not follow irradiation immediately.

9 Treatment monitoring Dose verification with PET: Comparison of dose planned and estimated from detected + activity. PET Limitations: Positron production does not follow irradiation immediately. Biological washout- activity carried away by metabolic processes. Low amount of + activity induced- low efficiency. Difficult online studies partial ring. Photons produce significant background. 9

10 Treatment monitoring in hadron therapy Prompt gammas emitted from nuclei excited during therapy and can be used for treatment monitoring. Emission correlated with dose. Emission ~ns after irradiation. Emitted in a continuous energy spectrum with energies of MeVs. Research on collimated and Compton cameras for gamma detection PG pe o sc e l Te protons Image PG creation map Energy (MeV) 10

3 interactions in 3 detectors (+ correct ordering): Energy determined lower

11 Compton camera configuration Scatterer + absorber: 2 interactions. Problems if the photon energy is unknown or if it can escape (MeV) Multilayer: 3 interactions in 3 detectors (+ correct ordering): Energy determined lower efficiency E1m e c2 cos (θ)=1 E 0 ( E 0 E 1) 2 E m c 1 E0 =E 1+ (E 2+ E e ) 2 1 cos θ2 11

Compton telescope @ IFIC/IFIMED Three detector layers: Continuous LaBr3 crystals. NO ABSORPTION REQUIRED High Compton probability.

12 Compton IFIC/IFIMED Three detector layers: Continuous LaBr3 crystals. NO ABSORPTION REQUIRED High Compton probability. High light yield => good energy and timing resolution. SiPM arrays. Aim at combination of: 2 int events (high efficiency) + 3 int events (high resolution). 12

Image reconstruction The cone surface is

13 Image reconstruction The cone surface is projected to the reconstruction volume The intersection of several cone surfaces yields the position of the source Reconstruction of point sources allows performance comparison in different configurations List mode ML-EM 5 events 1000 events Images shown: 15 iterations, number of events (~5k), Voxel = 1 mm3 13

14 Three-layer prototype System can measure 2/3 coincidence events simultaneously Detectors 2 and x36.0x5 mm3 32.4x36.0x10 mm3 Detector x27.2x5 mm3 14

15 Detectors Detector 1 Detectors 2 and mm 26.8 mm 27.2 mm 36 mm 15

Crystals LaBr3 crystals: 27.2 x 26.8 x 5 mm3. 32.5 x 35 x 5 mm3. 32.5 x 35 x 10mm3.

16 Crystals LaBr3 crystals: 27.2 x 26.8 x 5 mm x 35 x 5 mm x 35 x 10mm3. Tests with a PMT+ MCA: Energy resolution 3.5% 511 kev 16

17 Readout VATA64HDR16 ASIC from IDEAS 64 channels. Connected to a DAQ system made at IFIC- Valencia. Compact and portable system. 17

18 Coincidences board Coincidence board based on Xilinx Virtex FPGA. Coincidences between any two or all three planes - still independent image reconstruction. 18

19 Prototype User-friendly DAQ software also developed at IFIC-Valencia. 19

20 Detector characterization Na-22 and Y-88 Energy resolution: 7 % 511 kev Temperature calibration 1.25 mm FWHM Spatial resolution close to 1 mm FWHM 20

21 Laboratory tests: radioactive sources Tests in laboratory performed with two radioactive sources: Na-22: 511 and 1275 kev Y-88: 898 and 1836 kev Imaging capabilities tested in the range [0.5, 1.8] MeV. Na-22 Y kev 511 kev 1836 kev 1275 kev 21

22 Simulations - Measurements Experimental measurements reproduced by simulations with GATE 7.0 Na-22 with two planes Simulation Experimental 3.9 mm FWHM 4.2 mm FWHM Very good agreement 22

23 Two planes: different configurations Measurements with Na-22 selecting 1275 kev peak 4.2 mm FWHM 4.8 mm FWHM 2.6 mm FWHM 23

24 Two planes: different configurations Increasing distance between planes improves spatial resolution Detection efficiency decreases Balance efficiency and resolution Efficiency = 2.1 * mm FWHM Efficiency = 6.3 * mm FWHM 24

25 Two planes: images with different energies Sum Spectrum Na-22 Y kev 1275 kev 5.7 mm FWHM 4.1 mm FWHM 898 kev 1836 kev 4.1 mm FWHM 2.9 mm FWHM 25

26 Two planes: source at different positions Sources placed in different positions, separated 20 mm. Points reconstructed separately. Na-22 selecting 1275 kev peak Y-88 selecting 1836 kev peak 20 mm 26

27 Two planes: two sources imaged together Sum of energies in both detectors: Sum energy spectrum 511 kev 898 kev 1275 kev 1836 kev Y-88 Selecting 1275 and 1836 kev peaks. Sources separated 40 mm. Data from both sources reconstructed together. 40 mm Na-22 27

28 Three planes: Na mm 36 mm 40 mm 1275 kev 511 kev 5.5 mm FWHM 4.1 mm FWHM 28

29 Three planes: Y-88 Sum energy spectrum 898 kev 1836 kev 1836 kev 898 kev 4.3 mm FWHM 2.5 mm FWHM 29

30 Tests with protons at KVI-CART Tests at KVI-CART, AGOR cyclotron (Groningen). Proton beam, 150 MeV, ~ 10⁸ prot/sec. Graphite and PMMA targets. 30

31 Tests with protons at KVI-CART Data with two layers in coincidence. PMMA target shifted to simulate Bragg peak variations. Shift observed in the Bragg peak position. P. Solevi et al. Phys. Med. Biol. vol 61, num 14, p ,

Instituto de Física Corpuscular - IFIC and IFIMED (CSIC-UV) Valencia, Spain * and CERN, Geneva, Switzerland Daniel

32 In-Beam Tests with high energy gammas Enrique Muñoz, John Barrio, José Bernabéu, Ane Etxebeste, Carlos Lacasta, Josep F. Oliver, Pablo G. Ortega*, Carles Solaz and. Instituto de Física Corpuscular - IFIC and IFIMED (CSIC-UV) Valencia, Spain * and CERN, Geneva, Switzerland Daniel Bemmerer1, Fine Fiedler1, Fernando Hueso1, Katja Römer1, Louis Wagner1,2 Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany. 2 TU Dresden, Dresden, Germany. 1 Tests at HZDR 3MV Tandetron (Dresden). 32

33 Tests with high energy gammas Coincidences with 2/3 layers. Too low rate for three layers. Results with layers 1-3 (target at 43 mm, distance between planes 55 mm). Telescope placed in three positions wrt target. Nominal: -10, 0, +10 mm Reconstructed: -13.7, 0, mm PRELIMINARY RESULTS 33

34 Summary and conclusions Three-layer Compton prototype based on continuous LaBr3 crystals and SiPMs constructed at IFIC-Valencia. Studies of detector performance have been carried out with very good agreement with simulations. Successfully reconstructed images from sources in the range [ ] MeV. First tests in accelerator facilities carried out. Ongoing work is focused on combination of two and three interaction events and prototype performance improvement. 34

35 Acknowledgements This work was supported in part by the European Commission-FP7 through ENVISION project (G.A. num ). This work was supported in part through the Spanish Ministerio de Economía y competitividad/plan Nacional de I+D+i (FPA R) and IFIC's Center of Excellence Severo Ochoa (SEV ). Group members are supported through Ramón y Cajal, Atracció de Talent (UV), Generalitat Valenciana and CPAN contracts. Thank you! Related publications: P. Solevi et al. Phys. Med. Biol., 2016, volume 61, num 14, G. Llosá et al. Front. Oncol., 2016, volume 6:

Prompt gamma measurements for the verification of dose deposition in proton therapy. Contents. Two Proton Beam Facilities for Therapy and Research

Prompt gamma measurements for the verification of dose deposition in proton therapy Two Proton Beam Facilities for Therapy and Research Ion Beam Facilities in Korea 1. Proton therapy facility at National