Clinical implementation of respiratory-gated spot-scanning proton therapy: An efficiency analysis of active motion management.

Clinical implementation of respiratory-gated spot-scanning proton therapy: An efficiency analysis of active motion management. J Appl Clin Med Phys. 2019 Apr 10;: Authors: Gelover E, Deisher AJ, Herman MG, Johnson JE, Kruse JJ, Tryggestad EJ Abstract PURPOSE: The aim of this work is to describe the clinical implementation of respiratory-gated spot-scanning proton therapy (SSPT) for the treatment of thoracic and abdominal moving targets. The experience of our institution is summarized, from initial acceptance and commissioning tests to the development of standard clinical operating procedures for simulation, motion assessment, motion mitigation, treatment planning, and gated SSPT treatment delivery. MATERIALS AND METHODS: A custom respiratory gating interface incorporating the Real-Time Position Management System (RPM, Varian Medical Systems, Inc., Palo Alto, CA, USA) was developed in-house for our synchrotron-based delivery system. To assess gating performance, a motion phantom and radiochromic films were used to compare gated vs nongated delivery. Site-specific treatment planning protocols and conservative motion cutoffs were developed, allowing for free-breathing (FB), breath-holding (BH), or phase-gating (Ph-G). Room usage efficiency of BH and Ph-G treatments was retrospectively evaluated using beam delivery data retrieved from our record and verify system and DICOM files from patient-specific quality assurance (QA) procedures. RESULTS: More...
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research

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Abstract Positron emission tomography (PET) has been extensively studied and clinically investigated for dose verification in proton therapy. However, the production distributions of positron emitters are not proportional to the dose distribution. Thus, direct dose evaluation is limited when using the conventional PET-based approach. We propose a method for estimating the dose distribution from the positron emitter distributions using the maximum likelihood (ML) expectation maximization (EM) algorithm combined with filtering. In experiments to verify the effectiveness of the proposed method, mono-energetic and spr...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
Our institution utilizes both biologic and standard dose models in spot scanning proton treatment planning. This analysis examines the rates of post-treatment radiologic change as detected on post-treatment MRI scans, and toxicities for pediatric brain tumor patients treated during the first year of our institution ’s experience. Our novel biologic dose model was found to demonstrate greater volumetric overlap with the post-treatment radiologic changes, than the standard dose model.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
CONCLUSION: We have carried out an extensive measurement of H*(10) under different conditions. The shielding thickness of our PT facility is adequate to limit the dose to occupational worker and general public within the permissible stipulated limit. The data reported here can bridge the knowledge gap in ambient dose around PT facility and can also be used as a reference for any new and existing proton facility for inter comparison and validation. ADVANCES IN KNOWLEDGE: First extensive investigation of neutron and photon H*(10) around PT facility and can bridge the knowledge gap on ambient dose. PMID: 31287739 [P...
Source: The British Journal of Radiology - Category: Radiology Authors: Tags: Br J Radiol Source Type: research
o T, Khan R Abstract Radiochromic films have been widely studied for clinical dosimetry in conventional external beam radiation therapy. With an increase in practice of proton therapy, such films are being conveniently used; however, their spectroscopic characterization for this modality is lacking. This work investigated the response of the EBT3 radiochromic films irradiated in a Mevion S250™ clinical proton beam. Dose, dose rate, inter-batch, sensitivity, and linear energy transfer (LET) dependencies of the films were studied. Pieces of the radiochromic films from different batches were irradiated using a ...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
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Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
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Source: Acta Oncologica - Category: Cancer & Oncology Authors: Tags: Acta Oncol Source Type: research
Würl M Abstract Background: Precision small animal radiotherapy research is a young emerging field aiming to provide new experimental insights into tumor and normal tissue models in different microenvironments, to unravel complex mechanisms of radiation damage in target and non-target tissues and assess efficacy of novel therapeutic strategies. For photon therapy, modern small animal radiotherapy research platforms have been developed over the last years and are meanwhile commercially available. Conversely, for proton therapy, which holds potential for an even superior outcome than photon therapy, no commerci...
Source: Acta Oncologica - Category: Cancer & Oncology Authors: Tags: Acta Oncol Source Type: research
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Source: Acta Oncologica - Category: Cancer & Oncology Authors: Tags: Acta Oncol Source Type: research
Conclusion: FLASH dose rates were not achieved for conventional planning and clinical spot-scanning machines. As such, increased spot-wise beam intensities, spot-reduced planning, hypofractionation and arc-shoot-through plans were required to achieve FLASH compatible dose rates. PMID: 31241377 [PubMed - as supplied by publisher]
Source: Acta Oncologica - Category: Cancer & Oncology Authors: Tags: Acta Oncol Source Type: research
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Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research
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