Radiation Transport

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 61086 Experts worldwide ranked by ideXlab platform

P Papagiannis - One of the best experts on this subject based on the ideXlab platform.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part i single sources and bounded homogeneous geometries
    Medical Physics, 2010
    Co-Authors: K Zourari, E Pantelis, A Moutsatsos, L Petrokokkinos, P Karaiskos, L Sakelliou, E Georgiou, P Papagiannis
    Abstract:

    Purpose: The aim of this work is to validate a deterministic Radiation Transport based treatment planning system (TPS) for single I 192 r brachytherapy source dosimetry in homogeneous water geometries. Methods: TPS results were obtained using the deterministic Radiation Transport option of aBRACHYVISION v. 8.8 system for three characteristic source designs (VS2000, GMPlus HDR, and GMPlus PDR) with each source either centered in a 15 cm radius spherical water phantom, or positioned at varying distance away from the phantom center. Corresponding MC simulations were performed using the MCNPX code v.2.5.0 and source geometry models prepared using information provided by the manufacturers. Results: Comparison in terms of the AAPM TG-43 dosimetric formalism quantities, as well as dose rate distributions per unit air kerma strength with a spatial resolution of 0.1 cm, yielded close agreement between TPS and MC results for the sources centered in the phantom. Besides some regions close to the source longitudinal axes where discrepancies could be characterized as systematic, overall agreement for all three sources studied is comparable to the statistical (type A) uncertainty of MC simulations (1% at the majority of points in the geometry increasing to 2%–3% at points lying both away from the source center and close to the source longitudinal axis). A corresponding good agreement was also found between TPS and MC results for the sources positioned away from the phantom center. Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions regardless of the size or shape of a given geometry of dosimetric interest, and the position of a source within it. This is important since, as shown in the literature and summarized also in this work, these factors could introduce a significant dosimetric effect that is currently ignored in clinical treatment planning. It is concluded that the implementation of the deterministic Radiation Transport option of theBRACHYVISION v. 8.8 system for I 192 r brachytherapydosimetry in homogeneous water geometries yields results of comparable accuracy to the golden standard of Monte Carlo simulation, in clinically viable calculation times.

L Petrokokkinos - One of the best experts on this subject based on the ideXlab platform.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part i single sources and bounded homogeneous geometries
    Medical Physics, 2010
    Co-Authors: K Zourari, E Pantelis, A Moutsatsos, L Petrokokkinos, P Karaiskos, L Sakelliou, E Georgiou, P Papagiannis
    Abstract:

    Purpose: The aim of this work is to validate a deterministic Radiation Transport based treatment planning system (TPS) for single I 192 r brachytherapy source dosimetry in homogeneous water geometries. Methods: TPS results were obtained using the deterministic Radiation Transport option of aBRACHYVISION v. 8.8 system for three characteristic source designs (VS2000, GMPlus HDR, and GMPlus PDR) with each source either centered in a 15 cm radius spherical water phantom, or positioned at varying distance away from the phantom center. Corresponding MC simulations were performed using the MCNPX code v.2.5.0 and source geometry models prepared using information provided by the manufacturers. Results: Comparison in terms of the AAPM TG-43 dosimetric formalism quantities, as well as dose rate distributions per unit air kerma strength with a spatial resolution of 0.1 cm, yielded close agreement between TPS and MC results for the sources centered in the phantom. Besides some regions close to the source longitudinal axes where discrepancies could be characterized as systematic, overall agreement for all three sources studied is comparable to the statistical (type A) uncertainty of MC simulations (1% at the majority of points in the geometry increasing to 2%–3% at points lying both away from the source center and close to the source longitudinal axis). A corresponding good agreement was also found between TPS and MC results for the sources positioned away from the phantom center. Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions regardless of the size or shape of a given geometry of dosimetric interest, and the position of a source within it. This is important since, as shown in the literature and summarized also in this work, these factors could introduce a significant dosimetric effect that is currently ignored in clinical treatment planning. It is concluded that the implementation of the deterministic Radiation Transport option of theBRACHYVISION v. 8.8 system for I 192 r brachytherapydosimetry in homogeneous water geometries yields results of comparable accuracy to the golden standard of Monte Carlo simulation, in clinically viable calculation times.

K Zourari - One of the best experts on this subject based on the ideXlab platform.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part i single sources and bounded homogeneous geometries
    Medical Physics, 2010
    Co-Authors: K Zourari, E Pantelis, A Moutsatsos, L Petrokokkinos, P Karaiskos, L Sakelliou, E Georgiou, P Papagiannis
    Abstract:

    Purpose: The aim of this work is to validate a deterministic Radiation Transport based treatment planning system (TPS) for single I 192 r brachytherapy source dosimetry in homogeneous water geometries. Methods: TPS results were obtained using the deterministic Radiation Transport option of aBRACHYVISION v. 8.8 system for three characteristic source designs (VS2000, GMPlus HDR, and GMPlus PDR) with each source either centered in a 15 cm radius spherical water phantom, or positioned at varying distance away from the phantom center. Corresponding MC simulations were performed using the MCNPX code v.2.5.0 and source geometry models prepared using information provided by the manufacturers. Results: Comparison in terms of the AAPM TG-43 dosimetric formalism quantities, as well as dose rate distributions per unit air kerma strength with a spatial resolution of 0.1 cm, yielded close agreement between TPS and MC results for the sources centered in the phantom. Besides some regions close to the source longitudinal axes where discrepancies could be characterized as systematic, overall agreement for all three sources studied is comparable to the statistical (type A) uncertainty of MC simulations (1% at the majority of points in the geometry increasing to 2%–3% at points lying both away from the source center and close to the source longitudinal axis). A corresponding good agreement was also found between TPS and MC results for the sources positioned away from the phantom center. Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions regardless of the size or shape of a given geometry of dosimetric interest, and the position of a source within it. This is important since, as shown in the literature and summarized also in this work, these factors could introduce a significant dosimetric effect that is currently ignored in clinical treatment planning. It is concluded that the implementation of the deterministic Radiation Transport option of theBRACHYVISION v. 8.8 system for I 192 r brachytherapydosimetry in homogeneous water geometries yields results of comparable accuracy to the golden standard of Monte Carlo simulation, in clinically viable calculation times.

E Georgiou - One of the best experts on this subject based on the ideXlab platform.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part i single sources and bounded homogeneous geometries
    Medical Physics, 2010
    Co-Authors: K Zourari, E Pantelis, A Moutsatsos, L Petrokokkinos, P Karaiskos, L Sakelliou, E Georgiou, P Papagiannis
    Abstract:

    Purpose: The aim of this work is to validate a deterministic Radiation Transport based treatment planning system (TPS) for single I 192 r brachytherapy source dosimetry in homogeneous water geometries. Methods: TPS results were obtained using the deterministic Radiation Transport option of aBRACHYVISION v. 8.8 system for three characteristic source designs (VS2000, GMPlus HDR, and GMPlus PDR) with each source either centered in a 15 cm radius spherical water phantom, or positioned at varying distance away from the phantom center. Corresponding MC simulations were performed using the MCNPX code v.2.5.0 and source geometry models prepared using information provided by the manufacturers. Results: Comparison in terms of the AAPM TG-43 dosimetric formalism quantities, as well as dose rate distributions per unit air kerma strength with a spatial resolution of 0.1 cm, yielded close agreement between TPS and MC results for the sources centered in the phantom. Besides some regions close to the source longitudinal axes where discrepancies could be characterized as systematic, overall agreement for all three sources studied is comparable to the statistical (type A) uncertainty of MC simulations (1% at the majority of points in the geometry increasing to 2%–3% at points lying both away from the source center and close to the source longitudinal axis). A corresponding good agreement was also found between TPS and MC results for the sources positioned away from the phantom center. Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions regardless of the size or shape of a given geometry of dosimetric interest, and the position of a source within it. This is important since, as shown in the literature and summarized also in this work, these factors could introduce a significant dosimetric effect that is currently ignored in clinical treatment planning. It is concluded that the implementation of the deterministic Radiation Transport option of theBRACHYVISION v. 8.8 system for I 192 r brachytherapydosimetry in homogeneous water geometries yields results of comparable accuracy to the golden standard of Monte Carlo simulation, in clinically viable calculation times.

L Sakelliou - One of the best experts on this subject based on the ideXlab platform.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based brachytherapy treatment planning system part ii monte carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator
    Medical Physics, 2011
    Co-Authors: L Petrokokkinos, K Zourari, E Pantelis, A Moutsatsos, P Karaiskos, L Sakelliou, E Georgiou, Ioannis Seimenis, P Papagiannis
    Abstract:

    Purpose: The aim of this work is the dosimetric validation of a deterministic Radiation Transport based treatment planning system (BRACHYVISION™ v. 8.8, referred to as TPS in the following) for multiple I 192 r source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irRadiation plan employing seven VS2000 I 192 r high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo(MC) simulation results, as well as experimental results obtained using the VIP polymer gel–magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MCdose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the “shielded” segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%–30% at the edge of the “unshielded” segment of the geometry and even 2%–6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially shielded applicators.

  • dosimetric accuracy of a deterministic Radiation Transport based 192ir brachytherapy treatment planning system part i single sources and bounded homogeneous geometries
    Medical Physics, 2010
    Co-Authors: K Zourari, E Pantelis, A Moutsatsos, L Petrokokkinos, P Karaiskos, L Sakelliou, E Georgiou, P Papagiannis
    Abstract:

    Purpose: The aim of this work is to validate a deterministic Radiation Transport based treatment planning system (TPS) for single I 192 r brachytherapy source dosimetry in homogeneous water geometries. Methods: TPS results were obtained using the deterministic Radiation Transport option of aBRACHYVISION v. 8.8 system for three characteristic source designs (VS2000, GMPlus HDR, and GMPlus PDR) with each source either centered in a 15 cm radius spherical water phantom, or positioned at varying distance away from the phantom center. Corresponding MC simulations were performed using the MCNPX code v.2.5.0 and source geometry models prepared using information provided by the manufacturers. Results: Comparison in terms of the AAPM TG-43 dosimetric formalism quantities, as well as dose rate distributions per unit air kerma strength with a spatial resolution of 0.1 cm, yielded close agreement between TPS and MC results for the sources centered in the phantom. Besides some regions close to the source longitudinal axes where discrepancies could be characterized as systematic, overall agreement for all three sources studied is comparable to the statistical (type A) uncertainty of MC simulations (1% at the majority of points in the geometry increasing to 2%–3% at points lying both away from the source center and close to the source longitudinal axis). A corresponding good agreement was also found between TPS and MC results for the sources positioned away from the phantom center. Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions regardless of the size or shape of a given geometry of dosimetric interest, and the position of a source within it. This is important since, as shown in the literature and summarized also in this work, these factors could introduce a significant dosimetric effect that is currently ignored in clinical treatment planning. It is concluded that the implementation of the deterministic Radiation Transport option of theBRACHYVISION v. 8.8 system for I 192 r brachytherapydosimetry in homogeneous water geometries yields results of comparable accuracy to the golden standard of Monte Carlo simulation, in clinically viable calculation times.