Ein Verfahren zur in-vivo Kontrolle der Bestrahlungsplanung bei der Schwerionen-Tumortherapie mittels Positronen-Emissions-Tomographie

Lauckner, K.; Enghardt, W.; Hasch, B.G.; Hinz, Rainer; Pawelke, J.; Sobiella, M.; Freyer, R

doi:10.1515/bmte.1996.41.s1.194

Cited by 9 publications

(16 citation statements)

References 3 publications

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“…Secondly, there are also analogue influences as for the uncompensated simulation since there is a small residual motion within the 4D CT phase. These 2.5 mm (cf table 1) are below the spatial resolution in the mid plane of the PET scanner system which is about 5 mm due to the large detector crystals with a side length of 6.75 mm and the double-head geometry (Lauckner 1999). Anyway, the residual motion might slightly influence the 4D PT-PET images.…”

Section: Comparison With 3d Simulationmentioning

confidence: 94%

“…However, since 4D reconstruction algorithms are not the objective of this paper we simply calculate a 3D reconstruction for each of the generated amplitude sorted listmode data streams to verify the simulation results (section 3.2.2). The phase wise applied 3D maximum likelihood expectation maximization (MLEM) algorithm has been developed at Forschungszentrum Dresden-Rossendorf (Lauckner 1999, Hinz 2000, Pönisch et al 2003. Corrections for photon attenuation based on the corresponding CT phase and for the limited solid angle coverage of the scanner have been included.…”

Section: Pt-pet Data Simulation and Evaluationmentioning

confidence: 99%

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4D particle therapy PET simulation for moving targets irradiated with scanned ion beams

et al. 2013

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Particle therapy positron emission tomography (PT-PET) allows for an in vivo and in situ verification of applied dose distributions in ion beam therapy. Since the dose distribution cannot be extracted directly from the β(+)-activity distribution gained from the PET scan the validation is done by means of a comparison between the reconstructed β(+)-activity distributions from a PT-PET measurement and from a PT-PET simulation. Thus, the simulation software for generating PET data predicted from the treatment planning is an essential part of the dose verification routine. For the dose monitoring of intra-fractionally moving target volumes the PET data simulation needs to be upgraded by using time resolved (4D) algorithms to account correctly for the motion dependent displacement of the positron emitters. Moreover, it has to consider the time dependent relative movement between target volume and scanned beam to simulate the accurate positron emitter distribution generated during irradiation. Such a simulation program is presented which properly proceeds with motion compensated dose delivery by scanned ion beams to intra-fractionally moving targets. By means of a preclinical phantom study it is demonstrated that even the sophisticated motion-mitigated beam delivery technique of range compensated target tracking can be handled correctly by this simulation code. The new program is widely based on the 3D PT-PET simulation program which had been developed at the Helmholtz-Zentrum Dresden-Rossendorf, Germany (HZDR) for application within a pilot project to simulate in-beam PET data for about 440 patients with static tumor entities irradiated at the former treatment facility of the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany (GSI). A simulation example for a phantom geometry irradiated with a tracked (12)C-ion beam is presented for demonstrating the proper functionality of the program.

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Section: Comparison With 3d Simulationmentioning

confidence: 94%

Section: Pt-pet Data Simulation and Evaluationmentioning

confidence: 99%

4D particle therapy PET simulation for moving targets irradiated with scanned ion beams

et al. 2013

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“…Due to the limited angle geometry, the spatial resolution of the in-beam positron camera is dependent strongly on the position in the field of view. It is around 5 mm in the slice parallel to the detector heads (cf figure 1), 8 mm perpendicular to it and 12 mm off the center of the field of view, respectively (Lauckner 1999). Nevertheless, it has been shown by means of spreading out Bragg peak irradiation that the range resolution at the distal slope of the β + -activity distribution is less than 1 mm for carbon (Hinz 2001), protons (Parodi et al 2005) and for Helium ions (Fiedler et al 2006) in homogeneous targets.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, an extensive and accurate Monte Carlo simulation taking into account all processes starting with the impinging ions up to the detection of the annihilation γ -rays has been developed (Pönisch et al 2004). Both, measured and simulated β + -activity distribution undergo the same reconstruction process (Lauckner 1999). The evaluation of the irradiation is performed by means of a comparison of reconstructed images representing predicted and measured β + -activity distributions (Enghardt et al 2004a).…”

Section: Introductionmentioning

confidence: 99%

On the effectiveness of ion range determination from in-beam PET data

et al. 2010

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At present, in-beam positron emission tomography (PET) is the only method for in vivo and in situ range verification in ion therapy. At the GSI Helmholtzzentrum für Schwerionenforschung GmbH (GSI) Darmstadt, Germany, a unique in-beam PET installation has been operated from 1997 until the shut down of the carbon ion therapy facility in 2008. Therapeutic irradiation by means of (12)C ion beams of more than 400 patients have been monitored. In this paper a first quantitative study on the accuracy of the in-beam PET method to detect range deviations between planned and applied treatment in clinically relevant situations using simulations based on clinical data is presented. Patient treatment plans were used for performing simulations of positron emitter distributions. For each patient a range difference of + or - 6 mm in water was applied and compared to simulations without any changes. The comparisons were performed manually by six experienced evaluators for data of 81 patients. The number of patients required for the study was calculated using the outcome of a pilot study. The results indicate a sensitivity of (91 + or - 3)% and a specificity of (96 + or - 2)% for detecting an overrange, a reduced range is recognized with a sensitivity of (92 + or - 3)% and a specificity of (96 + or - 2)%. The positive and the negative predictive value of this method are 94% and 87%, respectively. The interobserver coefficient of variation is between 3 and 8%. The in-beam PET method demonstrated a high sensitivity and specificity for the detection of range deviations. As the range is a most indicative factor of deviations in the dose delivery, the promising results shown in this paper confirm the in-beam PET method as an appropriate tool for monitoring ion therapy.

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“…These probabilities were calculated using Siddon ray-tracing algorithm (Siddon 1985). In the case of the patient data, the system matrix was assessed using a code developed specifically for this application (Laukner 1999) and the sensitivity matrix was calculated in advance. The time information was modeled within p ij, δT by weighting each LOR by a Gaussian distribution with FWHM equal to the CRT and mean value equal to the expected position of the emission using δT (Groiselle and Glick 2004).…”

Section: Image Reconstructionmentioning

confidence: 99%

Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

Torres-Espallardó¹,

Diblen²,

Rohling³

et al. 2015

Phys. Med. Biol.

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Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scanner based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadron- Note Institute of Physics and Engineering in Medicine6 These authors contributed equally to the work. beam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options.

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Ein Verfahren zur in-vivo Kontrolle der Bestrahlungsplanung bei der Schwerionen-Tumortherapie mittels Positronen-Emissions-Tomographie

Cited by 9 publications

References 3 publications

4D particle therapy PET simulation for moving targets irradiated with scanned ion beams

4D particle therapy PET simulation for moving targets irradiated with scanned ion beams

On the effectiveness of ion range determination from in-beam PET data

Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

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