Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring - - PowerPoint PPT Presentation

▶
interaction vertex imaging ivi for carbon ion therapy
SMART_READER_LITE
LIVE PREVIEW

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring - - PowerPoint PPT Presentation

Apr 04, 2023 220 likes •393 views

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring a feasibility study E. Testa 1 , D. Dauvergne 1 , G. Dedes 1

slide-1
SLIDE 1

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring

a feasibility study

  • E. Testa1, D. Dauvergne1, G. Dedes1, N. Freud2,
  • P. Henriquet1, J. Krimmer1, J.M. L´

etang2, C. Ray1, M.-H. Richard1,2, F. Sauli3

1IPNL, France 2CREATIS, France 3TERA Foundation, Italy

ICTR-PHE 2012 Geneva, Switzerland

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 1 / 16

slide-2
SLIDE 2

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Outline

  • 1. Ion range verification
  • 2. Interaction Vertex Imaging principles
  • 3. Simulation tools
  • 4. Results

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 2 / 16

slide-3
SLIDE 3

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Rationale

Ideal control

  • 3D real-time dose control

Current challenge

  • 1D real-time ion-range

control

  • an energy-slice basis
  • or on a pencil-beam basis

Proton / carbon therapy

  • Beam intensities
  • Nuclear reactions

Typical 12C therapy treatment

Dose 1 GyE Irradiated volume 120 cm3

  • No. of energy slices

39

  • No. of C ions

Total 7 × 108 AVG per energy slice ∼ 2 × 107 AVG per pencil beam ∼ 105

  • M. Kraemer et al. 2000

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 3 / 16

slide-4
SLIDE 4

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Physical principles

Correlation between

  • ion range
  • nuclear reaction depth profile

Two kinds of radiations of relevance

  • β+ activity
  • Prompt radiations (γ, p)

Measurement of β+ activity (200 MeV/u 12C in PMMA) Simulation of prompt radiations

Target depth [cm] 0.5 1 1.5 2 2.5 3 counts/ion/mm 0.005 0.01 0.015 0.02 0.025 0.03

γ n p α nuclear reactions

C, PMMA target, GEANT4.9.4

12

95MeV/u

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 4 / 16

slide-5
SLIDE 5

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

5 modalities

β+ activity (PET)

  • Clinical use
  • off-beam (HIT, NIRS...)
  • in-beam (GSI)
  • Current research
  • Radioactive beams
  • TOF

Prompt radiations

  • Collimated

camera

  • Slit-hole

camera

  • Compton

camera

  • Interaction

Vertex Imaging

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 5 / 16

slide-6
SLIDE 6

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Principle and rationale

Principle

  • Detection of secondary protons emitted from incident ions
  • Reconstruction of nuclear reaction positions (“vertex”)
  • Comparison of measured and simulated distributions of

“reconstructed” vertices

Rationale

  • ++ Intrinsic detection efficiency ∼ 1
  • ++ “High” proton emission yield with 12C ion:

Proton yield ∼ γ-ray yield ∼ 10−1 incident 12C

  • - - Attenuation and straggling

in particular: low-energy protons emitted at the end of incident ion ranges Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 6 / 16

slide-7
SLIDE 7

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

2 imaging techniques

Imaging techniques

  • “Single-proton” imaging (SP-IVI)

Intersection of a secondary-proton trajectory with the incident-ion trajectory

  • “Double-proton” imaging (DP-IVI)

Intersection of 2 secondary-proton trajectories

Detectors

  • Tracker + beam hodoscope

(in coincidence) Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 7 / 16

slide-8
SLIDE 8

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Simulated setups

Tool

  • Geant4 9.1
  • Nuclear models

QMD (Quantum Molecular Dynamics)

Targets

  • Cylindrical
  • Head phantom

2 trackers

  • 10 × 10 cm2 pixelized detectors

(CMOS)

100 mm

C

20°

12

Cylindrical target

250 mm 50 mm 200 mm Tracker

C

Projectile-like fragment 20° p

12

Head phantom Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 8 / 16

slide-9
SLIDE 9

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Reconstruction

Basic reconstruction

  • Line intersection
  • Segment S : the smallest distance between trajectories
  • Vertex location: middle of S

Future reconstruction

  • Most Likely Path

Incident C

12

"Double-proton" imaging "Single-proton" imaging

(beam hodoscope) Reconstructed vertex Segment S Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 9 / 16

slide-10
SLIDE 10

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Simulation validations: nuclear reactions

Experimental setup

128 mm

C

Detection angle

12

Experimental setup

210 mm

Beam Target energy thickness (MeV) (mm) Our GSI 310 210 experiments GANIL 95 50 Gunzert-Marx et al. 200 128

Results

  • Good overall agreement

for E ≤ 200 MeV Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 10 / 16

slide-11
SLIDE 11

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Depth profile of generated vertices

100 mm

200 MeV/u C

12

PMMA target

  • Secondaries

Important contribution

  • Contrast

Relatively low: 1.3 Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 11 / 16

slide-12
SLIDE 12

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Depth profile of reconstructed vertices

100 mm

C

20°

12

Cylindrical target

  • Imaging technique

“Single proton” ⇒ higher statistics

  • Contrast

Promising (∼ 5) Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 12 / 16

slide-13
SLIDE 13

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Ion-range influence

Vertex Yield vs ion-range

  • Strong dependence

Fit function

  • y = a + b erf(x − IPP)
  • IPP: Inflection-Point Position

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 13 / 16

slide-14
SLIDE 14

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Ion-range resolution

Standard deviation of IPP

Number of incident ions 200 400 600 800 1000

3

10 × 0.5 1 1.5 2 2.5 3 3.5

Entries 1000 Mean 54.73 RMS 0.04046 ± 1.809

(mm) 45 50 55 60 65 Counts 50 100

Entries 1000 Mean 54.73 RMS 0.04046 ± 1.809

Position IPP

IPP Standard deviation of (mm)

(Beam energy: 200 MeV/u)

  • Homogeneous target
  • Millimetric resolution
  • n a pencil-beam basis (105 ions)

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 14 / 16

slide-15
SLIDE 15

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Conclusion

Feasibility study

  • Geant4 9.1 (validated against experimental data)
  • Elementary vertex reconstruction

Main results

  • “Single-proton” imaging choice
  • Real-time ion range verification (on a pencil-beam basis)

Henriquet et al., submitted to PMB Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 15 / 16

slide-16
SLIDE 16

Ion range verification Interaction Vertex Imaging principles Simulation tools Results Conclusion and perspectives

Perspectives

Detailed study of inhomogeneity influences

  • IVI sensitivity to inhomogeneities at the end of ion path

(low probabilibity of proton escape)

  • Inhomogeneities in the “exit channel material”

In-beam tests with CMOS detectors

  • Low and high energies
  • GANIL (95 MeV/u)
  • HIT (200-300 MeV/u)
  • Analysis in progress

Interaction Vertex Imaging (IVI) for carbon ion therapy monitoring 16 / 16