The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Benjamin W. Corn - One of the best experts on this subject based on the ideXlab platform.
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SU‐GG‐T‐516: Dose Calculation Verification for Stereotactic Treatment Plan
Medical Physics, 2008Co-Authors: D Schifter, Andrew A. Kanner, Benjamin W. CornAbstract:Purpose: Verification of SRSTreatment plans was a challenge in the early beginning of Stereotactic radio surgery. The large amount of dose deposited in a single fraction through a small collimator or MMLC was a cause of sleepless nights for many physicists. The traditional way was using a “hand calculation”. In some cases a special measurement in phantom was performed (while the patient was in the SRS ring). This work suggests a quick and accurate way using a standard TPS. Method and Materials: The original Treatment plans were developed on the Ergo ++ Treatment planning system ver. 1.6 for the 6X beam on a Beam Modulator (4mm leaves). All the plans were calculated with heterogeneity corrections turned on. For the purpose of “hand calculation” we used the built‐in second calculation in the Ergo system (the system provides an automatic and independent MU calculation mechanism). For the comparison we used the XIO software version 4.3.3. The beam was carefully modeled and commissioned on both systems for small field sizes. A total number of 20 plans were compared. The transfer was done using DICOM RT protocol. Results: The match between the calculation results on both 3D systems was excellent (in most cases less then 1% discrepancy). The 1D system showed larger errors (3–4% on head cases), which do not exist when we turned the heterogeneity corrections off. The DVH's and isodoses also showed very good agreement. The transfer and recalculation took about 15 minutes per plan. Conclusion: Using a full second 3D calculation on a separate TPS is a fast and accurate way to check SRS plans. It is usually available in most departments and it justifies the effort (if needed) of some extra modeling for small field sizes. “Hand calculation” is much less accurate, especially when inhomogeneities are present.
Robert E. Drzymala - One of the best experts on this subject based on the ideXlab platform.
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SU‐GG‐T‐533: Remote PC Application Access to a Stereotactic Treatment Planning System SQL Database
Medical Physics, 2010Co-Authors: Tianyu Zhao, Robert E. DrzymalaAbstract:Purpose: To implement remote access using Matlab to a PostgreSQL database, which supports the Leksell GammaPlan (LGP) version 8.1 Treatment planning system. Method and Materials: A postgreSQL Java Database Connectivity (JDBC) driver was downloaded from the official website of postgreSQL. The class path that specifies a series of files and directories, pointing to classes accessible to Matlab, must be edited to include the database driver. Table patients maintains information on patients. Table examinations maintains information on each examination. Table skulls maintains information on skull coordinates. Table plans minal information on each target . Table targets maintains information on each target. Table shots maintains information on each shot. lann examinations is related to table patients through examination ID. Table skulls is related to table examinations through examination ID. Table plans is also related to table examinations through examination ID. Table targets is related to table plans through plan ID. Table shots is related to table targets through target ID. Results: An application was implemented in Matlab. By entering the patient ID, any information about any Treatment performed on any specific patient, from patient's name and birthday to the shot time of each shot, could be retrieved remotely on a PC from the database in a well‐maintained data structure. The retrieved data were further used to verify LGP Treatment plans through independent dose calculation and display. Conclusion: A remote access to PostgreSQL database behind LGP is feasible in Matlab. Similar application could also be implemented in other environments like Visual C#. It is of great convenience for users who desire to develop their own applications that use information found in the LGP SQL database.
Dennis C. Shrieve - One of the best experts on this subject based on the ideXlab platform.
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Optimization of isocenter location for intensity modulated Stereotactic Treatment of small intracranial targets.
International journal of radiation oncology biology physics, 2009Co-Authors: Bill J. Salter, Martin Fuss, Vikren Sarkar, Brian Wang, Prema Rassiah-szegedi, Niko Papanikolaou, Scott Hollingshaus, Dennis C. ShrieveAbstract:Purpose To quantify the impact of isocenter location on Treatment plan quality for intensity-modulated Stereotactic Treatment of small intracranial lesions. Methods and Materials For 18 patients previously treated by Stereotactic-intensity modulated radiosurgery (IMRS) or intensity-modulated radiation therapy (IMRT), a retrospective virtual planning study was conducted wherein the impact of isocenter location on plan quality was measured. Treatment indications studied included six arteriovenous malformations, six acoustic neuromas, and six intracranial metastases, ranging in volume from 0.71 to 3.21 cm 3 (mean = 2.26 cm 3 ), 1.08 to 2.84 cm 3 (mean = 1.73 cm 3 ), and 0.19 to 2.30 cm 3 (mean = 0.79 cm 3 ), respectively. Variation of isocenter location causes the geometric grid of pencil beams into which the target is segmented for intensity-modulated Treatment to be altered. The impact of this pencil-beam-grid redefinition on achievable conformity index was quantified for three collimators (Varian Millennium 120; BrainLab MM3; Nomos binary Mimic) and three Treatment planning systems (TPS; Varian Eclipse v6.5; BrainLab BrainScan v5.31; Best-Nomos Corvus v6.2), resulting in the evaluation of 3,446 Treatment plans. Results For all patients, collimator, and TPS combinations studied, a significant variation in plan quality was observed as a function of isocenter and pencil-beam-grid relocation. Optimization of isocenter location resulted in Treatment plan conformity variations as large as 109% (min = 15%, mean=51%, max=109%). Conclusion Optimization of isocenter location for IMRT/IMRS Treatment of small intracranial lesions in which pencil-beam dimensions are comparable to target dimensions, can result in significant improvements in Treatment plan quality.
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SU‐GG‐T‐435: Optimization of Isocenter Location for Intensity Modulated Stereotactic Treatment of Intracranial Targets
Medical Physics, 2008Co-Authors: Bill J. Salter, Martin Fuss, Vikren Sarkar, Brian Wang, Niko Papanikolaou, Scott Hollingshaus, Matt Tobler, Dennis C. ShrieveAbstract:Purpose: To quantify the impact of isocenter re‐location/optimization on Treatment plan quality for intensity modulated Stereotactic Treatment of small intracranial lesions. Method and Materials: For 18 patients previously treated by Stereotactic intensity modulated radiosurgery (IMRS) or Stereotactic intensity modulated radiation therapy(IMRT), a retrospective virtual planning study was conducted wherein the impact of isocenter location on plan quality was measured. Lesions studied included 6 arteriovenous malformations (AVM), 6 acoustic neuromas (ACN) and 6 intracranial metastases, ranging in volume from 0.19–3.21 cm3. Variation of isocenter location causes the geometric grid of pencil beams into which the target is segmented for intensity modulated Treatment to be altered. The impact of this pencil beam grid redefinition on achievable conformity index (CI) may be significant for small lesions, where pencil beam size is similar to that of the lesion. Impact on CI was quantified for 3 different collimators (Varian Millennium 120; BrainLab MM3; Nomos binary Mimic) and 3 different Treatment planning systems (Varian Eclipse v7.3.1; BrainLab BrainScan v5.31; Nomos Corvus v6.2), resulting in the evaluation of 3,446 different Treatment plans. Results: For all patient, collimator and Treatment planning system combinations studied, a significant variation in plan quality was observed as a function of isocenter/pencil‐beam‐grid re‐location. Optimization of isocenter location resulted in Treatment plan conformity variations as large as 109% (min = 15%, mean = 53%, across all plans) with Millennium 120 mean = 36%, MM3 mean = 70% and Mimic mean = 51%. Conclusion: For intensity modulating Treatment plans, variation of isocenter location causes the geometric grid of pencil beams into which the target is segmented to be altered. Optimization of isocenter location for IMRT/IMRS Treatment of small intracranial lesions, where pencil beam dimensions are comparable to target dimensions, can result in significant improvements in Treatment plan quality.
Martin Fuss - One of the best experts on this subject based on the ideXlab platform.
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Image-guided radiation therapy
Der Radiologe, 2012Co-Authors: Judit Boda-heggemann, Matthias Guckenberger, Ute Ganswindt, Claus Belka, Hansjörg Wertz, Manuel Blessing, F. Wenz, Martin Fuss, Frank LohrAbstract:Radiotherapy technology has improved rapidly over the past two decades. New imaging modalities, such as positron emission (computed) tomography (PET, PET-CT) and high-resolution morphological and functional magnetic resonance imaging (MRI) have been introduced into the Treatment planning process. Image-guided radiation therapy (IGRT) with 3D soft tissue depiction directly imaging target and normal structures, is currently replacing patient positioning based on patient surface markers, frame-based intracranial and extracranial Stereotactic Treatment and partially also 2D field verification methods. On-line 3D soft tissue-based position correction unlocked the full potential of new delivery techniques, such as intensity-modulated radiotherapy, by safely delivering highly conformal dose distributions that facilitate dose escalation and hypofractionation. These strategies have already resulted in better clinical outcomes, e.g. in prostate and lung cancer and are expected to further improve radiotherapy results.
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Bildgeführte Strahlentherapie
Der Radiologe, 2012Co-Authors: Judit Boda-heggemann, Matthias Guckenberger, Ute Ganswindt, Claus Belka, Hansjörg Wertz, Manuel Blessing, F. Wenz, Martin Fuss, Frank LohrAbstract:Radiotherapy technology has improved rapidly over the past two decades. New imaging modalities, such as positron emission (computed) tomography (PET, PET-CT) and high-resolution morphological and functional magnetic resonance imaging (MRI) have been introduced into the Treatment planning process. Image-guided radiation therapy (IGRT) with 3D soft tissue depiction directly imaging target and normal structures, is currently replacing patient positioning based on patient surface markers, frame-based intracranial and extracranial Stereotactic Treatment and partially also 2D field verification methods. On-line 3D soft tissue-based position correction unlocked the full potential of new delivery techniques, such as intensity-modulated radiotherapy, by safely delivering highly conformal dose distributions that facilitate dose escalation and hypofractionation. These strategies have already resulted in better clinical outcomes, e.g. in prostate and lung cancer and are expected to further improve radiotherapy results. Die Strahlentherapie hat in den vergangenen 2 Dekaden von zahlreichen technischen Entwicklungen profitiert. Neue Bildgebungsmodalitäten wie Positronenemissionstomographie (PET, PET/CT) und hochauflösende morphologische und funktionelle MR-Sequenzen wurden in den Bestrahlungsplanungsprozess integriert. Die bildgesteuerte Strahlentherapie („image-guided radiation therapy“, IGRT) ermöglicht mittlerweile unmittelbar am Beschleuniger auch die 3-D-Darstellung von Weichgewebetumoren und ersetzt die Patientenpositionierung mittels Hautmarkern, rahmenbasierten stereotaktischen Verfahren im Kopf- und Körperstamm und teilweise auch die 2-D-Verifikation der Bestrahlungsfelder. IGRT gestattet die Realisierung des vollen Potenzials fortgeschrittener Bestrahlungstechniken wie der intensitätsmodulierten Strahlentherapie, mit deren Hilfe hochkonformale Dosisverteilungen realisiert werden können. Diese Strategien haben zu verbesserten klinischen Ergebnissen geführt und weitere Fortschritte sind zu erwarten.
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Optimization of isocenter location for intensity modulated Stereotactic Treatment of small intracranial targets.
International journal of radiation oncology biology physics, 2009Co-Authors: Bill J. Salter, Martin Fuss, Vikren Sarkar, Brian Wang, Prema Rassiah-szegedi, Niko Papanikolaou, Scott Hollingshaus, Dennis C. ShrieveAbstract:Purpose To quantify the impact of isocenter location on Treatment plan quality for intensity-modulated Stereotactic Treatment of small intracranial lesions. Methods and Materials For 18 patients previously treated by Stereotactic-intensity modulated radiosurgery (IMRS) or intensity-modulated radiation therapy (IMRT), a retrospective virtual planning study was conducted wherein the impact of isocenter location on plan quality was measured. Treatment indications studied included six arteriovenous malformations, six acoustic neuromas, and six intracranial metastases, ranging in volume from 0.71 to 3.21 cm 3 (mean = 2.26 cm 3 ), 1.08 to 2.84 cm 3 (mean = 1.73 cm 3 ), and 0.19 to 2.30 cm 3 (mean = 0.79 cm 3 ), respectively. Variation of isocenter location causes the geometric grid of pencil beams into which the target is segmented for intensity-modulated Treatment to be altered. The impact of this pencil-beam-grid redefinition on achievable conformity index was quantified for three collimators (Varian Millennium 120; BrainLab MM3; Nomos binary Mimic) and three Treatment planning systems (TPS; Varian Eclipse v6.5; BrainLab BrainScan v5.31; Best-Nomos Corvus v6.2), resulting in the evaluation of 3,446 Treatment plans. Results For all patients, collimator, and TPS combinations studied, a significant variation in plan quality was observed as a function of isocenter and pencil-beam-grid relocation. Optimization of isocenter location resulted in Treatment plan conformity variations as large as 109% (min = 15%, mean=51%, max=109%). Conclusion Optimization of isocenter location for IMRT/IMRS Treatment of small intracranial lesions in which pencil-beam dimensions are comparable to target dimensions, can result in significant improvements in Treatment plan quality.
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SU‐GG‐T‐435: Optimization of Isocenter Location for Intensity Modulated Stereotactic Treatment of Intracranial Targets
Medical Physics, 2008Co-Authors: Bill J. Salter, Martin Fuss, Vikren Sarkar, Brian Wang, Niko Papanikolaou, Scott Hollingshaus, Matt Tobler, Dennis C. ShrieveAbstract:Purpose: To quantify the impact of isocenter re‐location/optimization on Treatment plan quality for intensity modulated Stereotactic Treatment of small intracranial lesions. Method and Materials: For 18 patients previously treated by Stereotactic intensity modulated radiosurgery (IMRS) or Stereotactic intensity modulated radiation therapy(IMRT), a retrospective virtual planning study was conducted wherein the impact of isocenter location on plan quality was measured. Lesions studied included 6 arteriovenous malformations (AVM), 6 acoustic neuromas (ACN) and 6 intracranial metastases, ranging in volume from 0.19–3.21 cm3. Variation of isocenter location causes the geometric grid of pencil beams into which the target is segmented for intensity modulated Treatment to be altered. The impact of this pencil beam grid redefinition on achievable conformity index (CI) may be significant for small lesions, where pencil beam size is similar to that of the lesion. Impact on CI was quantified for 3 different collimators (Varian Millennium 120; BrainLab MM3; Nomos binary Mimic) and 3 different Treatment planning systems (Varian Eclipse v7.3.1; BrainLab BrainScan v5.31; Nomos Corvus v6.2), resulting in the evaluation of 3,446 different Treatment plans. Results: For all patient, collimator and Treatment planning system combinations studied, a significant variation in plan quality was observed as a function of isocenter/pencil‐beam‐grid re‐location. Optimization of isocenter location resulted in Treatment plan conformity variations as large as 109% (min = 15%, mean = 53%, across all plans) with Millennium 120 mean = 36%, MM3 mean = 70% and Mimic mean = 51%. Conclusion: For intensity modulating Treatment plans, variation of isocenter location causes the geometric grid of pencil beams into which the target is segmented to be altered. Optimization of isocenter location for IMRT/IMRS Treatment of small intracranial lesions, where pencil beam dimensions are comparable to target dimensions, can result in significant improvements in Treatment plan quality.
Alan C Hartford - One of the best experts on this subject based on the ideXlab platform.
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case report of a near medical event in Stereotactic radiotherapy due to improper units of measure from a Treatment planning system
Medical Physics, 2011Co-Authors: David J Gladstone, S Li, Lesley A Jarvis, Alan C HartfordAbstract:Purpose: The authors hereby notify the Radiation Oncology community of a potentially lethal error due to improper implementation of linear units of measure in a Treatment planning system. The authors report an incident in which a patient was nearly mistreated during a Stereotactic radiotherapy procedure due to inappropriate reporting of Stereotactic coordinates by the radiation therapyTreatment planning system in units of centimeter rather than in millimeter. The authors suggest a method to detect such errors during Treatment planning so they are caught and corrected prior to the patient positioning for Treatment on the Treatment machine.Methods: Using preTreatment imaging, the authors found that Stereotactic coordinates are reported with improper linear units by a Treatment planning system. The authors have implemented a redundant, independent method of Stereotactic coordinate calculation.Results: Implementation of a double check of Stereotactic coordinates via redundant, independent calculation is simple and accurate. Use of this technique will avoid any future error in Stereotactic Treatment coordinates due to improper linear units, transcription, or other similar errors.Conclusions: The authors recommend an independent double check of Stereotactic Treatment coordinates during the Treatment planning process in order to avoid potential misTreatment of patients.