In silico comparison of photons versus carbon ions in single fraction therapy of lung cancer

Anderle, Kristjan; Stroom, J.; Pimentel, N.; Greco, Carlo; Durante, Marco; Graeff, Christian

doi:10.1016/j.ejmp.2016.08.014

Cited by 15 publications

(15 citation statements)

References 173 publications

(246 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the location of the target in the heart, cardiac exposure will by necessity be high. Particle therapy according to planning studies can reduce cardiac doses drastically in comparison to photons in lung cancer patients, which also appears to be true for arrhythmia ablation . If the additional challenges of particles for moving targets can be overcome to assure safe dose coverage, these dosimetric advantages will be a strong factor in patient selection and risk‐benefit analysis.…”

Section: Discussionmentioning

confidence: 99%

Noninvasive cardiac arrhythmia ablation with particle beams

Graeff

Bert

2018

Medical Physics

Self Cite

View full text Add to dashboard Cite

Cardiac arrhythmias are a major health burden, associated with reduced quality of life and substantial morbidity and mortality. Current therapy includes moderately effective medication and catheter‐based ablation of arrhythmogenic substrates in the heart. Catheter interventions frequently have to be repeated due to recurrent arrhythmia, can have rare but severe side‐effects and are less suited especially for potentially lethal left ventricular tachycardia. Noninvasive alternatives are therefore warranted. Photon and ion beam radiotherapy has been studied in animal models and first patient cases have been reported using photons. Ion beams might offer the possibility to greatly reduce dose to surrounding healthy tissue, including critical cardiac substructures. Based on a recently conducted animal study, we report advantages and disadvantages of 4D‐ion beam therapy, and strategies necessary for a clinical transition. Motion management of both respiration and heartbeat are discussed, as well as range uncertainty resulting from both regular motion and interfractional anatomic changes. Image guidance both in 3D and 4D has to be employed for a safe irradiation, but also population‐based data on motion variability and time behavior of interfractional changes are necessary. Range verification could play a crucial role at least during development of clinical protocols. For clinical realization, it appears necessary to suppress or conformally mitigate the large respiratory motion to avoid normal tissue complications. Cardiac motion has to be incorporated into treatment planning, either through adequate range‐considering internal margins or through more conformal strategies such as ECG‐based gating or even 4D‐optimization. The latter strategies would necessitate online 4D image guidance.

show abstract

Section: Discussionmentioning

confidence: 99%

Noninvasive cardiac arrhythmia ablation with particle beams

Graeff

Bert

2018

Medical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Target and OAR contours, which were delineated in the end‐inhale reference phase, were propagated to other motion phases through deformable image registration (DIR). The clinical target volume (CTV) was 1.6 cm

^{3}

in size and was situated in the left superior lung 21 …”

Section: Methodsmentioning

confidence: 99%

“…The clinical target volume (CTV) was 1.6 cm 3 in size and was situated in the left superior lung. 21 The plan was recalculated for a carbon ion therapy treatment using a fraction dose of 3.5 GyE in accordance with a regimen of 70 GyE in 20 fractions prescribed for centrally located disease at Shanghai Proton and Heavy Ion Center (SPHIC). 22 The biologically effective doses were computed using LEM IV assuming an 𝛼∕𝛽 of 6 and 2 for the target and for OARs, respectively.…”

Section: Patient Data and Treatment Planningmentioning

confidence: 99%

Compensating for beam modulation due to microscopic lung heterogeneities in carbon ion therapy treatment planning

Paz

Baumann²,

Weber

et al. 2021

Medical Physics

Self Cite

View full text Add to dashboard Cite

To predict and mitigate for the degradation in physical and biologically effective dose distributions of particle beams caused by microscopic heterogeneities in lung tissue. Materials and Methods: The TRiP98 treatment planning system was adapted to account for the beam-modulating effect of heterogeneous lung tissue in physical and biological inverse treatment planning. The implementation employs an analytical model that derives the degradation from the established "modulation power" parameter P mod and the total water-equivalent thickness of lung parenchyma traversed by the beam. Beam modulation was reproduced through an on-the-fly convolution of the reference Bragg curve with Gaussian kernels depending on the modulation power of lung tissue (upstream). For biological doses, the degradation was determined by modulating dose-averaged 𝛼, 𝛽, and LET distributions. Carbon SOBP measurements behind lung substitute material were performed to validate the code. The implementation was then applied to a phantom and patient case. Results: Experimental results show the passage through a 20-cm Gammex LN300 slab led to a decrease in target coverage and broadening of the SOBP distal fall-off. However, dose coverage was regained through optimization. A good agreement between calculated and measured SOBPs was also found. In addition, a patient case study revealed a 3.2% decrease in D 95 from degradation (P mod = 450 𝜇m),which was reduced to a 0.4% difference after optimization. Furthermore,widening of the RBE distribution beyond the target distal edge was observed. This implies an increased degradation in the biological dose, which could be harmful to healthy tissues distal to the target. Conclusions: This is the first implementation capable of compensating for lung dose perturbations, which is more effective than margin extensions. A larger patient study is needed to examine the observed modulation in the RBE distribution and judge the clinical relevance also in IMPT, where margins might prove insufficient to recover target coverage.

show abstract

“…The DIR was performed with Plastimatch, using two successive registrations with a B-Spline algorithm [ 11 ]. The quality of the 4DCT DIR was assessed using the platform 3D Slicer [ 12 ], in particular using the Registration Quality Module [ 13 ], which was developed by external contributors as a set of tools that can be incorporated into 3D Slicer. The evaluation was performed through visual inspection and numerical quantification, such as the determinant of the Jacobian matrix (JD) of the vector field, inverse consistency error (ICE) and mean absolute difference.…”

Section: Methodsmentioning

confidence: 99%

Significance of intra-fractional motion for pancreatic patients treated with charged particles

et al. 2018

View full text Add to dashboard Cite

BackgroundUncertainties associated with the delivery of treatment to moving organs might compromise the accuracy of treatment. This study explores the impact of intra-fractional anatomical changes in pancreatic patients treated with charged particles delivered using a scanning beam. The aim of this paper is to define the potential source of uncertainties, quantify their effect, and to define clinically feasible strategies to reduce them.MethodsThe study included 14 patients treated at our facility with charged particles (protons or 12C) using intensity modulated particle therapy (IMPT). Treatment plans were optimized using the Treatment Planning System (TPS) Syngo® RT Planning. The pre-treatment dose distribution under motion (4D) was simulated using the TPS TRiP4D and the dose delivered for some of the treatment fractions was reconstructed. The volume receiving at least 95% of the prescribed dose (V95CTV) and the target dose homogeneity were evaluated. The results from the 4D dose calculations were compared with dose distributions in the static case and its variation correlated with the internal motion amplitude and plan modulation, through the Pearson correlation coefficient, as well the significant p-value. The concept of the modulation index (MI) was introduced to assess the degree of modulation of IMPT plans, through the quantification of intensity gradients between neighboring pencil beams.ResultsThe induced breathing motion together with dynamic beam delivery results in an interplay effect, which affects the homogeneity and target coverage of the dose distribution. This effect is stronger (∆V95CTV > 10%) for patients with tumor motion amplitude above 5 mm and a highly modulated dose distribution between and within fields. The MI combined with the internal motion amplitude is shown to correlate with the target dose degradation and a lack of plan robustness against range and positioning uncertainties.ConclusionsUnder internal motion the use of inhomogeneous plans results in a decrease in the dose homogeneity and target coverage of dose distributions in comparison to the static case. Plan robustness can be improved by using multiple beams and avoiding beam entrance directions susceptible to density changes. 4D dose calculations support the selection of the most suitable plan for the specific patient’s anatomy.Electronic supplementary materialThe online version of this article (10.1186/s13014-018-1060-8) contains supplementary material, which is available to authorized users.

show abstract

In silico comparison of photons versus carbon ions in single fraction therapy of lung cancer

Cited by 15 publications

References 173 publications

Noninvasive cardiac arrhythmia ablation with particle beams

Noninvasive cardiac arrhythmia ablation with particle beams

Compensating for beam modulation due to microscopic lung heterogeneities in carbon ion therapy treatment planning

Significance of intra-fractional motion for pancreatic patients treated with charged particles

Contact Info

Product

Resources

About