Treatment Planning Studies in Patient Data With Scanned Carbon Ion Beams for Catheter‐Free Ablation of Atrial Fibrillation

Constantinescu, A.; Lehmann, H. Immo; Packer, Douglas L.; Bert, Christoph; Durante, Marco; Graeff, Christian

doi:10.1111/jce.12888

Cited by 26 publications

(45 citation statements)

References 38 publications

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“…The physical properties of charged particle beams–inverted dose-profile with major energy release at a specific tissue depth at the end of the particle range (Bragg peak)–enable irradiation of deep seated target volumes with significant sparing of surrounding structures when compared to state-of-the-art X-ray treatments20. In case of catheter-free arrhythmia ablation, this translates into decrease in dose-exposure of myocardium as well as mediastinal structures21. In addition to irradiation of very large myocardial volumes, studies using radiation therapy with photon beams for catheter-free isolation of the RSPV have created accidental heart block and fistulas of mediastinal organs in the porcine model22.…”

Section: Discussionmentioning

confidence: 99%

Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

Lehmann

Graeff

Simoniello

et al. 2016

Sci Rep

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117

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High-energy ion beams are successfully used in cancer therapy and precisely deliver high doses of ionizing radiation to small deep-seated target volumes. A similar noninvasive treatment modality for cardiac arrhythmias was tested here. This study used high-energy carbon ions for ablation of cardiac tissue in pigs. Doses of 25, 40, and 55 Gy were applied in forced-breath-hold to the atrioventricular junction, left atrial pulmonary vein junction, and freewall left ventricle of intact animals. Procedural success was tracked by (1.) in-beam positron-emission tomography (PET) imaging; (2.) intracardiac voltage mapping with visible lesion on ultrasound; (3.) lesion outcomes in pathohistolgy. High doses (40–55 Gy) caused slowing and interruption of cardiac impulse propagation. Target fibrosis was the main mediator of the ablation effect. In irradiated tissue, apoptosis was present after 3, but not 6 months. Our study shows feasibility to use high-energy ion beams for creation of cardiac lesions that chronically interrupt cardiac conduction.

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Section: Discussionmentioning

confidence: 99%

Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

Lehmann

Graeff

Simoniello

et al. 2016

Sci Rep

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117

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“…While some groups are investigating complete non-invasive cardiac SRS with carbon ions [16, 17] or MRI-Linear-Accelerators [18], our goal was to analyze the general feasibility of cardiac SRS for paroxysmal AF in humans using treatment planning simulations and include possible options without fiducial implantation for the CyberKnife. The optimal non-invasive tracking method would be completely marker-less [19] which is already available for lung tumors for the CyberKnife [20].…”

Section: Introductionmentioning

confidence: 99%

Treatment Planning Considerations for Robotic Guided Cardiac Radiosurgery for Atrial Fibrillation

Blanck¹,

Ipsen²,

Chan³

et al. 2016

Cureus

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PurposeRobotic guided stereotactic radiosurgery has recently been investigated for the treatment of atrial fibrillation (AF). Before moving into human treatments, multiple implications for treatment planning given a potential target tracking approach have to be considered. Materials & MethodsTheoretical AF radiosurgery treatment plans for twenty-four patients were generated for baseline comparison. Eighteen patients were investigated under ideal tracking conditions, twelve patients under regional dose rate (RDR = applied dose over a certain time window) optimized conditions (beam delivery sequence sorting according to regional beam targeting), four patients under ultrasound tracking conditions (beam block of the ultrasound probe) and four patients with temporary single fiducial tracking conditions (differential surrogate-to-target respiratory and cardiac motion). ResultsWith currently known guidelines on dose limitations of critical structures, treatment planning for AF radiosurgery with 25 Gy under ideal tracking conditions with a 3 mm safety margin may only be feasible in less than 40% of the patients due to the unfavorable esophagus and bronchial tree location relative to the left atrial antrum (target area). Beam delivery sequence sorting showed a large increase in RDR coverage (% of voxels having a larger dose rate for a given time window) of 10.8-92.4% (median, 38.0%) for a 40-50 min time window, which may be significant for non-malignant targets. For ultrasound tracking, blocking beams through the ultrasound probe was found to have no visible impact on plan quality given previous optimal ultrasound window estimation for the planning CT. For fiducial tracking in the right atrial septum, the differential motion may reduce target coverage by up to -24.9% which could be reduced to a median of -0.8% (maximum, -12.0%) by using 4D dose optimization. The cardiac motion was also found to have an impact on the dose distribution, at the anterior left atrial wall; however, the results need to be verified.ConclusionRobotic AF radiosurgery with 25 Gy may be feasible in a subgroup of patients under ideal tracking conditions. Ultrasound tracking was found to have the lowest impact on treatment planning and given its real-time imaging capability should be considered for AF robotic radiosurgery. Nevertheless, advanced treatment planning using RDR or 4D respiratory and cardiac dose optimization may be still advised despite using ideal tracking methods.

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“…For example, higher particle flux than the currently typical maximum of 2 × 10 8 /s, potentially smaller beam diagnostic modules (e.g., 10 × 10 cm 2 ) with increased read‐out rates allowing faster scanning, and implementation of novel methods to quickly change the ion's energy can allow very quick delivery of such treatments. Even doses of up to 40 Gy result in less than 10 10 carbon ions per field (three fields per patient) and could thus be delivered in a single, flat‐top energy‐modulated cycle of the NIRS synchrotron . Such preliminary estimations show the potential of dedicated solutions if the current knowledge is further expanded toward a specific treatment.…”

Section: Requirements For a Clinical Applicationmentioning

confidence: 99%

“…Subsequently, photons expose large tissue volumes to low or medium dose levels, while appropriate selection of the typically 2–4 fields of a particle therapy can result in complete sparing of critical structures (Fig. ) . Given the high fraction doses that are currently investigated for arrhythmia ablation, dose constraints on normal tissue are highly relevant, comparable to stereotactic radiosurgery for lung cancer .…”

Section: Introductionmentioning

confidence: 99%

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Noninvasive cardiac arrhythmia ablation with particle beams

Graeff

Bert

2018

Medical Physics

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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.

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Treatment Planning Studies in Patient Data With Scanned Carbon Ion Beams for Catheter‐Free Ablation of Atrial Fibrillation

Cited by 26 publications

References 38 publications

Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

Treatment Planning Considerations for Robotic Guided Cardiac Radiosurgery for Atrial Fibrillation

Noninvasive cardiac arrhythmia ablation with particle beams

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