Calculation of radiation therapy dose using all particle Monte Carlo transport

• US 5,870,697 A
• Filed: 03/05/1996
• Issued: 02/09/1999
• Est. Priority Date: 03/05/1996
• Status: Expired due to Term

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Hartmann-Siantar, Christine L., Chandler, William P., Rathkopf, James A.
• Primary Examiner(s): Stamber, Eric W.
• Application Number:
  US08/610,917
• Time in Patent Office: 1,071 Days
• Field of Search: 364/527, 364/413.13, 364/413.14, 364/413.19, 364/413.15, 364/413.16, 378/65, 378/97, 378/901, 378/62, 378/92, 378/153, 378/159, 378/207, 378/8, 128/898, 705/3, 600/425, 600/410, 600/509, 600/1, 600/407, 395/185.01, 395/183.13, 250/263, 250/475.2, 250/505.1, 250/580, 702/179
• US Class Current: 702/179
• CPC Class Codes: A61N 2005/1034 Monte Carlo type methods; particle tracking
• CPC Class Codes: A61N 5/1031 using a specific method of dose optimization
• CPC Class Codes: A61N 5/1042 with spatial modulation of the radiation beam within the treatment head
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

Claims

1. An apparatus, comprising:

a computer readable memory; and

a computer program loaded into said computer readable memory, wherein said computer program comprises means for producing a 3-dimensional map of a radiation dose delivered to a patient, said means for producing a 3-dimensional map comprising a computer implemented process for producing a 3-dimensional map of a radiation dose delivered to a patient, comprising;

constructing patient-dependent information necessary for a Monte-Carlo transport calculation, wherein the step of constructing patient dependent-information comprises;

determining user-specified options from an input of (i) Monte Carlo parameters, (ii) physics options and (iii) output options, to set switches for code control;

determining the number of energy groups for transport of each particle type from nuclear/atomic/electron data to provide the number of energy groups for each particle type;

using computed tomography (CT) information to define dimensions and material composition for each CT voxel from an input of (i) user options comprising user-specified thresholds for processing CT scans and (ii) a CT scan array to contribute to the production of a material specification array;

reading user-drawn contours that describe patient structures and modifying said material specification arrays from an input of a second set of user options comprising user-drawn contours, to complete the production of said material specification array and to provide a standard deviation zone identification array;

reading user input specifying each radiation beam source from an input of radiation source specifications comprising external beam characteristics and modifiers to provide radiation source angular and energy distributions and arrays describing beam delivery components;

reading user input specifying each internal (brachytherapy) source from an input of an internal radiation source specification to provide radiation source angular and energy distributions;

completing the final setup for material arrays from an input of material composition data which is defined internally within the code to provide problem dependent material and isotope specification arrays;

reading nuclear and atomic data and constructing transport arrays from an input of (i) said nuclear/atomic/electron data, (ii) said number of energy groups for each particle type and (iii) said problem-dependent material and isotope specification arrays to provide (i) nuclear and atomic transport data arrays, (ii) heavy charged particle transport data arrays and (iii) energy group structure for each particle type; and

reading electron data and constructing transport arrays from an input of (i) said nuclear/atomic/electron data and (ii) said problem-dependent material and isotope specification arrays to produce electron transport data arrays;

executing said Monte-Carlo transport calculation, wherein the step of executing the Monte Carlo transport calculation comprises;

selecting particle attributes for a primary particle arising from an external radiation beam from an input of (i) radiation source angular and energy distributions, (ii) arrays describing beam delivery components, (iii) material data, (iv) nuclear and atomic transport data arrays and (v) number and energy group structure for each particle type, and to contribute a first portion to the provision of attributes of one particle, wherein said attributes comprise energy, location, direction and type;

selecting particle attributes for a primary particle arising from an internal radiation source from an input of radiation source angular and energy distributions to contribute a second portion to the provision of said attributes of one particle;

selecting a particle that has been created by an interaction of another particle in a transport mesh from an input of secondary particle arrays to provide a third portion to and complete the provision of said attributes of one particle;

(i) tracking a neutron through said transport mesh, (ii) recording energy deposited by said neutron and (iii) storing attributes of secondary particles produced in a secondary particle array from an input of (i) attributes of one particle (said neutron), (ii) switches set for code control, (iii) a material specification array, (iv) material data, (v) nuclear transport data arrays, and (vi) the number and energy group structure for said neutrons, to provide secondary particle arrays for neutrons and a 3-D energy deposit map for neutrons;

(i) tracking a photon through said transport mesh, (ii) recording energy deposited by said photon and (iii) storing attributes of secondary particles produced in secondary particle arrays for photons from an input of (i) attributes of one photon particle, (ii) said switches set for code control, (iii) said material specification arrays, (iv) said material data, (v) said atomic transport data arrays, and (vi) number and energy group structure for photons, to provide secondary particle arrays for photons and a 3-D energy deposit map for photons;

(i) tracking a heavy charged particle through said transport mesh, (ii) recording the energy deposited by said heavy charged particle and (iii) storing the attributes of secondary particles produced in secondary particle arrays for heavy charged particles from an input of (i) said switch settings for code control, (ii) said material specification array, (iii) said material data, (iv) said nuclear transport data arrays, (v) heavy charged particle transport data arrays and (vi) the number and energy group structure for heavy charged particles to provide secondary particle arrays for heavy charged particles and a 3-D deposit map for heavy charged particles;

(i) tracking a primary electron through said transport mesh, (ii) recording the energy deposited by said electron and (iii) storing the attributes of secondary particles produced in secondary particle arrays for primary electrons from an input of (i) the attributes of one particle (primary electron), (ii) said switch settings for code control, (iii) said material specification array, (iv) said material data, (v) electron transport data arrays and (vi) said number and energy group structure for said electrons to provide secondary particle arrays for primary electrons and a 3-D energy deposit map for primary electrons;

(i) tracking secondary electrons through said transport mesh, (ii) recording the energy deposited by said secondary electron and (iii) storing the attributes of secondary particles produced (secondary electrons) in secondary particle arrays for secondary electrons from an input of (i) the attributes of one particle (a secondary electron), (ii) said switch settings for code control, (iii) said material specification array, (iv) said material data, (v) said electron transport data arrays and (vi) said number and energy group structure for electrons to provide said secondary particle arrays for secondary electrons and a 3-D energy deposit map for secondary electrons;

adding all 3-D energy deposit maps calculated over a batch to a 3-D energy deposit map for the problem from an input of a 3-D energy deposit map calculated for a single batch to provide an integral 3-D energy deposit map;

updating the arrays necessary for a standard deviation calculation with energy deposit information determined from each said batch from an input of said integral 3-D energy deposit map and a standard deviation zone ID array to provide standard deviation precalculation arrays; and

calculating standard deviation from an input of said standard deviation precalculation arrays to provide standard deviation arrays; and

producing, from said patient-dependent information and said Monte-Carlo transport calculation, a 3-dimensional map of the dose delivered to said patient.

2. The apparatus of claim 1, wherein said means for producing a 3-dimensional map of a radiation dose delivered to a patient comprise:

means for constructing patient-dependent information comprising;

a material specification array including information on tissue classification;

material data including material composition and density;

particle data including particle mass and charge;

nuclear and atomic transport data arrays;

radiation source angular and energy distributions; and

arrays describing beam delivery components;

means for producing from said patient-dependent information;

a 3-dimensional map of the energy that has been deposited in said patient; and

a 3-dimensional map of the standard deviation of the energy deposited in said patient; and

means for formatting a 3-dimensional dose map from (i) said material specification array, (ii) said material data, (iii) said 3-dimensional map of the energy that has been deposited in said patient and (iv) said 3-dimensional map of the standard deviation of the energy deposited in said patient.

3. A computer implemented process for producing a 3-dimensional map of a radiation dose delivered to a patient, comprising:

constructing patient-dependent information necessary for a Monte-Carlo transport calculation, wherein the step of constructing patient dependent-information comprises;

determining user-specified options from an input of (i) Monte Carlo parameters, (ii) physics options and (iii) output options, to set switches for code control;

determining the number of energy groups for transport of each particle type from nuclear/atomic/electron data to provide the number of energy groups for each particle type;

using computed tomography (CT) information to define dimensions and material composition for each CT voxel from an input of (i) user options comprising user-specified thresholds for processing CT scans and (ii) a CT scan array to contribute to the production of a material specification array;

reading user-drawn contours that describe patient structures and modifying said material specification arrays from an input of a second set of user options comprising user-drawn contours, to complete the production of said material specification array and to provide a standard deviation zone identification array;

reading user input specifying each radiation beam source from an input of radiation source specifications comprising external beam characteristics and modifiers to provide radiation source angular and energy distributions and arrays describing beam delivery components;

reading user input specifying each internal (brachytherapy) source from an input of an internal radiation source specification to provide radiation source angular and energy distributions;

completing the final setup for material arrays from an input of material composition data which is defined internally within the code to provide problem dependent material and isotope specification arrays;

reading nuclear and atomic data and constructing transport arrays from an input of (i) said nuclear/atomic/electron data, (ii) said number of energy groups for each particle type and (iii) said problem-dependent material and isotope specification arrays to provide (i) nuclear and atomic transport data arrays, (ii) heavy charged particle transport data arrays and (iii) energy group structure for each particle type; and

reading electron data and constructing transport arrays from an input of (i) said nuclear/atomic/electron data and (ii) said problem-dependent material and isotope specification arrays to produce electron transport data arrays;

executing said Monte-Carlo transport calculation, wherein the step of executing said Monte Carlo transport calculation comprises;

selecting particle attributes for a primary particle arising from an external radiation beam from an input of (i) radiation source angular and energy distributions, (ii) arrays describing beam delivery components, (iii) material data, (iv) nuclear and atomic transport data arrays and (v) number and energy group structure for each particle type, and to contribute a first portion to the provision of attributes of one particle, wherein said attributes comprise energy, location, direction and type;

selecting particle attributes for a primary particle arising from an internal radiation source from an input of radiation source angular and energy distributions to contribute a second portion to the provision of said attributes of one particle;

selecting a particle that has been created by an interaction of another particle in a transport mesh from an input of secondary particle arrays to provide a third portion to and complete the provision of said attributes of one particle;

(i) tracking a neutron through said transport mesh, (ii) recording energy deposited by said neutron and (iii) storing attributes of secondary particles produced in a secondary particle array from an input of (i) attributes of one particle (said neutron), (ii) switches set for code control, (iii) a material specification array, (iv) material data, (v) nuclear transport data arrays, and (vi) the number and energy group structure for said neutrons, to provide secondary particle arrays for neutrons and a 3-D energy deposit map for neutrons;

(i) tracking a photon through said transport mesh, (ii) recording energy deposited by said photon and (iii) storing attributes of secondary particles produced in secondary particle arrays for photons from an input of (i) attributes of one photon particle, (ii) said switches set for code control, (iii) said material specification arrays, (iv) said material data, (v) said atomic transport data arrays, and (vi) number and energy group structure for photons, to provide secondary particle arrays for photons and a 3-D energy deposit map for photons;

(i) tracking a heavy charged particle through said transport mesh, (ii) recording the energy deposited by said heavy charged particle and (iii) storing the attributes of secondary particles produced in secondary particle arrays for heavy charged particles from an input of (i) said switch settings for code control, (ii) said material specification array, (iii) said material data, (iv) said nuclear transport data arrays, (v) heavy charged particle transport data arrays and (vi) the number and energy group structure for heavy charged particles to provide secondary particle arrays for heavy charged particles and a 3-D deposit map for heavy charged particles;

(i) tracking a primary electron through said transport mesh, (ii) recording the energy deposited by said electron and (iii) storing the attributes of secondary particles produced in secondary particle arrays for primary electrons from an input of (i) the attributes of one particle (primary electron), (ii) said switch settings for code control, (iii) said material specification array, (iv) said material data, (v) electron transport data arrays and (vi) said number and energy group structure for said electrons to provide secondary particle arrays for primary electrons and a 3-D energy deposit map for primary electrons;

(i) tracking secondary electrons through said transport mesh, (ii) recording the energy deposited by said secondary electron and (iii) storing the attributes of secondary particles produced (secondary electrons) in secondary particle arrays for secondary electrons from an input of (i) the attributes of one particle (a secondary electron), (ii) said switch settings for code control, (iii) said material specification array, (iv) said material data, (v) said electron transport data arrays and (vi) said number and energy group structure for electrons to provide said secondary particle arrays for secondary electrons and a 3-D energy deposit map for secondary electrons;

adding all 3-D energy deposit maps calculated over a batch to a 3-D energy deposit map for the problem from an input of a 3-D energy deposit map calculated for a single batch to provide an integral 3-D energy deposit map;

updating the arrays necessary for a standard deviation calculation with energy deposit information determined from each said batch from an input of said integral 3-D energy deposit map and a standard deviation zone ID array to provide standard deviation precalculation arrays; and

calculating standard deviation from an input of said standard deviation precalculation arrays to provide standard deviation arrays; and

producing, from said patient-dependent information and said Monte-Carlo transport calculation, a 3-dimensional map of the dose delivered to said patient.

4. The method of claim 3, wherein the step of producing, from said patient dependent information and said Monte Carlo transport calculation, a 3 dimensional map of the dose delivered to said patient, comprises:

writing a problem summary into an ASCII output file;

calculating the dose from an integral 3-D map of energy deposited; and

writing out a 3-D dose map from an input of said integral 3-D energy deposit array and said standard deviation arrays, wherein said 3-D dose map is written in a form selected from a group consisting of ASCII and binary.

5. A computer implemented process for producing a 3-dimensional map of a radiation dose delivered to a patient, comprising:

constructing patient-dependent information necessary for a Monte-Carlo transport calculation, wherein the step of constructing patient dependent-information comprises;

determining user-specified options from an input of (i) Monte Carlo parameters, (ii) physics options and (iii) output options, to set switches for code control;

determining the number of energy groups for transport of each particle type from nuclear/atomic/electron data to provide the number of energy groups for each particle type;

using computed tomography (CT) information to define dimensions and material composition for each CT voxel from an input of (i) user options comprising user-specified thresholds for processing CT scans and (ii) a CT scan array to contribute to the production of a material specification array;

reading user-drawn contours that describe patient structures and modifying said material specification arrays from an input of a second set of user options comprising user-drawn contours, to complete the production of said material specification array and to provide a standard deviation zone identification array;

reading user input specifying each radiation beam source from an input of radiation source specifications comprising external beam characteristics and modifiers to provide radiation source angular and energy distributions and arrays describing beam delivery components;

reading user input specifying each internal (brachytherapy) source from an input of an internal radiation source specification to provide radiation source angular and energy distributions;

completing the final setup for material arrays from an input of material composition data which is defined internally within the code to provide problem dependent material and isotope specification arrays;

reading nuclear and atomic data and constructing transport arrays from an input of (i) said nuclear/atomic/electron data, (ii) said number of energy groups for each particle type and (iii) said problem-dependent material and isotope specification arrays to provide (i) nuclear and atomic transport data arrays, (ii) heavy charged particle transport data arrays and (iii) energy group structure for each particle type; and

reading electron data and constructing transport arrays from an input of (i) said nuclear/atomic/electron data and (ii) said problem-dependent material and isotope specification arrays to produce electron transport data arrays;

executing said Monte-Carlo transport calculation; and

producing, from said patient-dependent information and said Monte-Carlo transport calculation, a 3-dimensional map of the dose delivered to said patient.

6. A computer implemented process for producing a 3-dimensional map of a radiation dose delivered to a patient, comprising:

constructing patient-dependent information necessary for a Monte-Carlo transport calculation;

executing said Monte-Carlo transport calculation;

wherein the step of executing the Monte Carlo transport calculation comprises;

selecting particle attributes for a primary particle arising from an external radiation beam from an input of (i) radiation source angular and energy distributions, (ii) arrays describing beam delivery components, (iii) material data, (iv) nuclear and atomic transport data arrays and (v) number and energy group structure for each particle type, and to contribute a first portion to the provision of attributes of one particle, wherein said attributes comprise energy, location, direction and type;

selecting particle attributes for a primary particle arising from an internal radiation source from an input of radiation source angular and energy distributions to contribute a second portion to the provision of said attributes of one particle;

selecting a particle that has been created by an interaction of another particle in a transport mesh from an input of secondary particle arrays to provide a third portion to and complete the provision of said attributes of one particle;

(i) tracking a neutron through said transport mesh, (ii) recording energy deposited by said neutron and (iii) storing attributes of secondary particles produced in a secondary particle array from an input of (i) attributes of one particle (said neutron), (ii) switches set for code control, (iii) a material specification array, (iv) material data, (v) nuclear transport data arrays, and (vi) the number and energy group structure for said neutrons, to provide secondary particle arrays for neutrons and a 3-D energy deposit map for neutrons;

(i) tracking a photon through said transport mesh, (ii) recording energy deposited by said photon and (iii) storing attributes of secondary particles produced in secondary particle arrays for photons from an input of (i) attributes of one photon particle, (ii) said switches set for code control, (iii) said material specification arrays, (iv) said material data, (v) said atomic transport data arrays, and (vi) number and energy group structure for photons, to provide secondary particle arrays for photons and a 3-D energy deposit map for photons;

(i) tracking a heavy charged particle through said transport mesh, (ii) recording the energy deposited by said heavy charged particle and (iii) storing the attributes of secondary particles produced in secondary particle arrays for heavy charged particles from an input of (i) said switch settings for code control, (ii) said material specification array, (iii) said material data, (iv) said nuclear transport data arrays, (v) heavy charged particle transport data arrays and (vi) the number and energy group structure for heavy charged particles to provide secondary particle arrays for heavy charged particles and a 3-D deposit map for heavy charged particles;

(i) tracking a primary electron through said transport mesh, (ii) recording the energy deposited by said electron and (iii) storing the attributes of secondary particles produced in secondary particle arrays for primary electrons from an input of (i) the attributes of one particle (primary electron), (ii) said switch settings for code control, (iii) said material specification array, (iv) said material data, (v) electron transport data arrays and (vi) said number and energy group structure for said electrons to provide secondary particle arrays for primary electrons and a 3-D energy deposit map for primary electrons;

(i) tracking secondary electrons through said transport mesh, (ii) recording the energy deposited by said secondary electron and (iii) storing the attributes of secondary particles produced (secondary electrons) in secondary particle arrays for secondary electrons from an input of (i) the attributes of one particle (a secondary electron), (ii) said switch settings for code control, (iii) said material specification array, (iv) said material data, (v) said electron transport data arrays and (vi) said number and energy group structure for electrons to provide said secondary particle arrays for secondary electrons and a 3-D energy deposit map for secondary electrons;

adding all 3-D energy deposit maps calculated over a batch to a 3-D energy deposit map for the problem from an input of a 3-D energy deposit map calculated for a single batch to provide an integral 3-D energy deposit map;

updating the arrays necessary for a standard deviation calculation with energy deposit information determined from each said batch from an input of said integral 3-D energy deposit map and a standard deviation zone ID array to provide standard deviation precalculation arrays; and

calculating standard deviation from an input of said standard deviation precalculation arrays to provide standard deviation arrays; and

producing, from said patient-dependent information and said Monte-Carlo transport calculation, a 3-dimensional map of the dose delivered to said patient.