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Range Verification Methods in Particle Therapy: Underlying Physics and Monte Carlo Modeling.

Kraan AC - Front Oncol (2015)

Bottom Line: Currently, uncertainties in particle range lead to the employment of safety margins, at the expense of treatment quality.We include research studies and clinically applied methods.For each of the techniques, we point out advantages and disadvantages, as well as clinical challenges still to be addressed, focusing on MC simulation aspects.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, National Institute for Nuclear Physics (INFN), University of Pisa , Pisa , Italy.

ABSTRACT
Hadron therapy allows for highly conformal dose distributions and better sparing of organs-at-risk, thanks to the characteristic dose deposition as function of depth. However, the quality of hadron therapy treatments is closely connected with the ability to predict and achieve a given beam range in the patient. Currently, uncertainties in particle range lead to the employment of safety margins, at the expense of treatment quality. Much research in particle therapy is therefore aimed at developing methods to verify the particle range in patients. Non-invasive in vivo monitoring of the particle range can be performed by detecting secondary radiation, emitted from the patient as a result of nuclear interactions of charged hadrons with tissue, including β (+) emitters, prompt photons, and charged fragments. The correctness of the dose delivery can be verified by comparing measured and pre-calculated distributions of the secondary particles. The reliability of Monte Carlo (MC) predictions is a key issue. Correctly modeling the production of secondaries is a non-trivial task, because it involves nuclear physics interactions at energies, where no rigorous theories exist to describe them. The goal of this review is to provide a comprehensive overview of various aspects in modeling the physics processes for range verification with secondary particles produced in proton, carbon, and heavier ion irradiation. We discuss electromagnetic and nuclear interactions of charged hadrons in matter, which is followed by a summary of some widely used MC codes in hadron therapy. Then, we describe selected examples of how these codes have been validated and used in three range verification techniques: PET, prompt gamma, and charged particle detection. We include research studies and clinically applied methods. For each of the techniques, we point out advantages and disadvantages, as well as clinical challenges still to be addressed, focusing on MC simulation aspects.

No MeSH data available.


Experimental neutron spectra (97) at different angles from a thin 12C target bombarded with a 290 MeV/u 12C beam compared with Japanese QMD calculations (98), the Bertini INC model (32) coupled to an evaporation model (HIC), the Los Alamos version of the Quark-Gluon String Model used as a stand alone code LAQGSM03.03 [see Ref. (29)], and with MCNP6 using the LAQGSM03.03 event-generator [see Ref. (94)]. Reproduced from Ref. (94).
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Figure 8: Experimental neutron spectra (97) at different angles from a thin 12C target bombarded with a 290 MeV/u 12C beam compared with Japanese QMD calculations (98), the Bertini INC model (32) coupled to an evaporation model (HIC), the Los Alamos version of the Quark-Gluon String Model used as a stand alone code LAQGSM03.03 [see Ref. (29)], and with MCNP6 using the LAQGSM03.03 event-generator [see Ref. (94)]. Reproduced from Ref. (94).

Mentions: Longitudinal and lateral dose distributions in MCNPX and MCNP5 have been validated for proton therapy by various research groups (90–92). The modeling of nuclear interactions with MCNP6 with the CEM and the LAQGSM models has been recently extensively validated by Mashnik et al. (94–96). Fragmentation measurements from a vast set of recent and older experiments were compared to MCNP6 simulations, as documented in comprehensive Validation and Verification (V&V) Los Alamos reports (94, 95). Comparisons included total cross sections and double differential energy spectra for neutrons, protons, and light fragments (up to 4He) produced during irradiation of protons, light and heavy ions impinging on many different homogeneous targets. Figure 8 demonstrates an example of the validation, showing a measured double differential neutron spectrum for a thin 12C target bombarded with a 290 MeV/u 12C beam, together with MCNP6 predictions with the LAQGDM model. A very good agreement was obtained.


Range Verification Methods in Particle Therapy: Underlying Physics and Monte Carlo Modeling.

Kraan AC - Front Oncol (2015)

Experimental neutron spectra (97) at different angles from a thin 12C target bombarded with a 290 MeV/u 12C beam compared with Japanese QMD calculations (98), the Bertini INC model (32) coupled to an evaporation model (HIC), the Los Alamos version of the Quark-Gluon String Model used as a stand alone code LAQGSM03.03 [see Ref. (29)], and with MCNP6 using the LAQGSM03.03 event-generator [see Ref. (94)]. Reproduced from Ref. (94).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493660&req=5

Figure 8: Experimental neutron spectra (97) at different angles from a thin 12C target bombarded with a 290 MeV/u 12C beam compared with Japanese QMD calculations (98), the Bertini INC model (32) coupled to an evaporation model (HIC), the Los Alamos version of the Quark-Gluon String Model used as a stand alone code LAQGSM03.03 [see Ref. (29)], and with MCNP6 using the LAQGSM03.03 event-generator [see Ref. (94)]. Reproduced from Ref. (94).
Mentions: Longitudinal and lateral dose distributions in MCNPX and MCNP5 have been validated for proton therapy by various research groups (90–92). The modeling of nuclear interactions with MCNP6 with the CEM and the LAQGSM models has been recently extensively validated by Mashnik et al. (94–96). Fragmentation measurements from a vast set of recent and older experiments were compared to MCNP6 simulations, as documented in comprehensive Validation and Verification (V&V) Los Alamos reports (94, 95). Comparisons included total cross sections and double differential energy spectra for neutrons, protons, and light fragments (up to 4He) produced during irradiation of protons, light and heavy ions impinging on many different homogeneous targets. Figure 8 demonstrates an example of the validation, showing a measured double differential neutron spectrum for a thin 12C target bombarded with a 290 MeV/u 12C beam, together with MCNP6 predictions with the LAQGDM model. A very good agreement was obtained.

Bottom Line: Currently, uncertainties in particle range lead to the employment of safety margins, at the expense of treatment quality.We include research studies and clinically applied methods.For each of the techniques, we point out advantages and disadvantages, as well as clinical challenges still to be addressed, focusing on MC simulation aspects.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, National Institute for Nuclear Physics (INFN), University of Pisa , Pisa , Italy.

ABSTRACT
Hadron therapy allows for highly conformal dose distributions and better sparing of organs-at-risk, thanks to the characteristic dose deposition as function of depth. However, the quality of hadron therapy treatments is closely connected with the ability to predict and achieve a given beam range in the patient. Currently, uncertainties in particle range lead to the employment of safety margins, at the expense of treatment quality. Much research in particle therapy is therefore aimed at developing methods to verify the particle range in patients. Non-invasive in vivo monitoring of the particle range can be performed by detecting secondary radiation, emitted from the patient as a result of nuclear interactions of charged hadrons with tissue, including β (+) emitters, prompt photons, and charged fragments. The correctness of the dose delivery can be verified by comparing measured and pre-calculated distributions of the secondary particles. The reliability of Monte Carlo (MC) predictions is a key issue. Correctly modeling the production of secondaries is a non-trivial task, because it involves nuclear physics interactions at energies, where no rigorous theories exist to describe them. The goal of this review is to provide a comprehensive overview of various aspects in modeling the physics processes for range verification with secondary particles produced in proton, carbon, and heavier ion irradiation. We discuss electromagnetic and nuclear interactions of charged hadrons in matter, which is followed by a summary of some widely used MC codes in hadron therapy. Then, we describe selected examples of how these codes have been validated and used in three range verification techniques: PET, prompt gamma, and charged particle detection. We include research studies and clinically applied methods. For each of the techniques, we point out advantages and disadvantages, as well as clinical challenges still to be addressed, focusing on MC simulation aspects.

No MeSH data available.