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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.


Top: 1-D profile along the z-axis of the measured (black) and MC simulated activity (red) induced by a 95 MeV proton beam impinging on a PMMA target during 118 s. Bottom: the same but for the 2 Gy treatment plan, delivered in 145 s. Inter-spill (left), beam-off (center), and all together (right) are displayed separately. Adapted from Ref. (116).
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Figure 10: Top: 1-D profile along the z-axis of the measured (black) and MC simulated activity (red) induced by a 95 MeV proton beam impinging on a PMMA target during 118 s. Bottom: the same but for the 2 Gy treatment plan, delivered in 145 s. Inter-spill (left), beam-off (center), and all together (right) are displayed separately. Adapted from Ref. (116).

Mentions: Kraan et al. used FLUKA to predict the PET activity measured in homogeneous targets during and after proton irradiation with an in-beam PET system at the CATANA cyclotron (119) and at the CNAO treatment facility (116). Figure 10 shows an example of measurements performed at CNAO for irradiation of a PMMA phantom with a homogeneous proton beam (top figures) and a SOBP (bottom figures), together with the FLUKA simulation, for various acquisition time intervals. A good agreement between data and MC simulations was found.


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

Kraan AC - Front Oncol (2015)

Top: 1-D profile along the z-axis of the measured (black) and MC simulated activity (red) induced by a 95 MeV proton beam impinging on a PMMA target during 118 s. Bottom: the same but for the 2 Gy treatment plan, delivered in 145 s. Inter-spill (left), beam-off (center), and all together (right) are displayed separately. Adapted from Ref. (116).
© Copyright Policy
Related In: Results  -  Collection

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

Figure 10: Top: 1-D profile along the z-axis of the measured (black) and MC simulated activity (red) induced by a 95 MeV proton beam impinging on a PMMA target during 118 s. Bottom: the same but for the 2 Gy treatment plan, delivered in 145 s. Inter-spill (left), beam-off (center), and all together (right) are displayed separately. Adapted from Ref. (116).
Mentions: Kraan et al. used FLUKA to predict the PET activity measured in homogeneous targets during and after proton irradiation with an in-beam PET system at the CATANA cyclotron (119) and at the CNAO treatment facility (116). Figure 10 shows an example of measurements performed at CNAO for irradiation of a PMMA phantom with a homogeneous proton beam (top figures) and a SOBP (bottom figures), together with the FLUKA simulation, for various acquisition time intervals. A good agreement between data and MC simulations was found.

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.