PEREGRINE Program

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PEREGRINE Program
Christine Hartmann Siantar Medical Technology
Program Physics and Advanced Technology
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Outline

• Radiation for cancer therapy
• Early-stage cancer external beam radiation
  therapy
• PEREGRINE Monte Carlo tools
• Widespread cancer molecular targeted radiation
  therapy

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Cancer
1.3 million people get cancer every year Your
chances of getting cancer are about 1 in 2 (men)
or 1 in 3 (women) The cancer survival rate is 50
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Early-stage cancer conventional radiotherapy
50 of cancer patients receive external beam
radiation therapy External beam radiation therapy
fails to eradicate the primary tumor in 1 out of
3 patients
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The system of conventional radiotherapy
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Monte Carlo transport
Monte Carlo transport allows stochastic solution
for complex 3D radiation transport equations that
are difficult to solve analytically
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Monte Carlo calculations offer several advantages

• Accurate dose calculations for all materials, all
  geometries
• Simultaneous determination of dose deposition and
  image formation
• Detailed information about how dose is deposited
  in matter

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Monte Carlo is for everyone

• Ultimately, the ability of Monte Carlo methods to
  solve arbitrarily complex problems is limited
  only by
• How well the physical system is understood
• The computational time it takes to adequately
  sample the solution space
• Because of the continual explosion in computer
  speed and affordability, Monte Carlo has now
  become practical for solving the problem of
  radiation transport in the radiation therapy
  patient, at computation times that are consistent
  with practical use in the clinic

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PEREGRINE

• PEREGRINE is a software/hardware system that
  implements the Monte Carlo method for the
  specific purpose of simulating medical radiation
  delivery
• The major goals in its development have been to
  design a system specifically tailored to
  radiation therapy applications and make Monte
  Carlo transport fast enough to be practical for
  day-to-day treatment planning

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PEREGRINE system description
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PEREGRINE starts reporting results almost
immediately
2 mm resolution Full volume calculation
2 min
10 min
20 min
Transport Time 2 min
Transport Time 20 min
Transport Time 10 min
Monte Carlo allows a new level of flexibility in
calculation times
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You can calculate all beams at the same time with
minimal penalty
2 mm resolution 5 standard deviation
1 beam
4 beams
22 beams
9 min
15 min
15 min
Calculation times depends on resolution and
statistical quality, not number of beams
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Accurate materials handling
Variable Density Bone, Muscle
Variable Density Water
Anatomy
Monte Carlo explicitly accounts for materials in
the patient
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Imaging electron transport
Anatomy
Dose Distribution
Electron Transport Map
18 MV Parallel oblique fields
Monte Carlo explicitly accounts for electron
transport in the patient
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Optimization
Optimized IMRT
7 Field Conformal
We have found a way to incorporate 3D Monte Carlo
methods into the optimization process
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Online quality assurance
Treatment Room Image
Quantitative Exit Dose Map
Simulator Room Radiograph
PEREGRINE simulation Varian 2100C 6 MV photon
beam, treatment field
PEREGRINE simulation 60 kVp x-rays
PEREGRINE simulation Varian 2100C 6 MV photon
beam, no block
Monte Carlo enable accurate predictions of the
dose delivered to the patient and may improve the
quality of online images
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Requirements for a microscopic model
Electron Physics
DNA Description
Free Radical Chemistry
A successful model requires accurate knowledge
of electron physics, DNA and free radical
chemistry
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System for molecular targeted radiation therapy
CT / SPECT Scan
Treatment
Treatment Plan
Provide 3D anatomical and radiation-distribution
information
Administer radiation based on predetermined dose
estimates
Combine anatomy and radiation-uptake data to
estimate dose per administered activity
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Dose determination for molecular-targeted therapy

• Determine the activity map in the patient
• Account for time-dependent changes in activity
• Estimate dose in the tumor and critical organs

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Molecular PEREGRINE

• We have developed an internal source capability,
  with input consistent with a SPECT scan
• Monte Carlo dose simulation is shown for a
  uniform 131I source distribution in a lung tumor

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In situ microanalysis at LLNL
In situ microanalysis provides a capability to
quantitatively map the intracellular distribution
of labeled pharmaceutical agents
Cell data provided by Ian Hutcheon (LLNL CMS)
By combining LLNL capabilities in in situ
microanalysis with Mirage microscopic-scale
radiation transport simulations, we will be able
to accurately predict radiation damage at the
cellular level
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PEREGRINE team
Physics and Advanced Technologies Directorate
Medical Technologies Program
PEREGRINE (Medical Simulations) C. L. Hartmann
Siantar PEREGRINE Program Leader R. S. Walling
Program Manager Computations Engineering Physics
Ron House Dewey Garrett Tom Daly Don
Jong Clark Powell Marie-Anne Descalle Timur
Ismagilov
UCSF Bruce Faddegon Jean Pouliot Lynn
Verhey Cynthia Chuang