Limits...
First year experience with newly developed Leksell Gamma Knife Perfexion.

Bhatnagar JP, Novotny J, Niranjan A, Kondziolka D, Flickinger J, Lunsford D, Huq MS - J Med Phys (2009)

Bottom Line: Excellent agreement is also found between the dosimetric characteristics of LGK PFX and LGK 4C for the 4 and 8 mm collimators.The set up and treatment of patients on the LGK PFX is much more efficient since it is a fully automated system.The system also provides more options to generate plan with high dosimetric conformity.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, Neurological Surgery, University of Pittsburgh Cancer Institute, Pittsburgh, USA.

ABSTRACT
A new model of Leksell Gamma Knife(R) (LGK), known as Perfexion (LGK PFX), was introduced by Elekta Instrument, AB, Sweden, in 2006. This model has a radically different design from the earlier models U, B, C and 4C. Dosimetric characteristics of LGK PFX, technical differences between LGK PFX and LGK 4C, experience gained with acceptance testing and commissioning of the LGK PFX, and comparison between LGK PFX and LGK 4C are presented in this study. Excellent agreement is found between the manufacturers recommended values of absorbed dose rate, relative output factors for 4 and 8 mm collimators, coincidence of mechanical and dosimetric isocenter, FWHM for beam profiles for various collimators and those reported in the present study. Excellent agreement is also found between the dosimetric characteristics of LGK PFX and LGK 4C for the 4 and 8 mm collimators. Examples of clinical cases treated with LGK PFX and impact of LGK PFX on workflow and dosimetric conformity of treatment planning is also given. The set up and treatment of patients on the LGK PFX is much more efficient since it is a fully automated system. The system also provides more options to generate plan with high dosimetric conformity.

No MeSH data available.


Related in: MedlinePlus

Example of using composite shots for the LGK PFX. To shape 50% isodose line and cover irregular target volume (meningioma) different combination of composite shots was used (see combination of eight sectors for each of eight different shots used). Different sector colors indicate different collimator size used: yellow – 4 mm, green – 8 mm, red – 16 mm and blue – blocked beams. Cross hatched sectors represent sectors that were automatically blocked by the treatment planning system to reduce dose to critical structures
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Figure 0003: Example of using composite shots for the LGK PFX. To shape 50% isodose line and cover irregular target volume (meningioma) different combination of composite shots was used (see combination of eight sectors for each of eight different shots used). Different sector colors indicate different collimator size used: yellow – 4 mm, green – 8 mm, red – 16 mm and blue – blocked beams. Cross hatched sectors represent sectors that were automatically blocked by the treatment planning system to reduce dose to critical structures

Mentions: The most significant change seen in treatment planning is the ability to generate a single isocenter composed of different beam diameters. Such a composite shot allows for optimized dose distribution shape for the individual shots.[12–15] Setup of any sector combination is almost free of time penalty during patient treatment since sector position changes are done automatically within five seconds. An example of using composite shots for the LGK PFX is given in Figure 3. Similarly, an example of using dynamic shaping for the LGK PFX is given in Figure 4.


First year experience with newly developed Leksell Gamma Knife Perfexion.

Bhatnagar JP, Novotny J, Niranjan A, Kondziolka D, Flickinger J, Lunsford D, Huq MS - J Med Phys (2009)

Example of using composite shots for the LGK PFX. To shape 50% isodose line and cover irregular target volume (meningioma) different combination of composite shots was used (see combination of eight sectors for each of eight different shots used). Different sector colors indicate different collimator size used: yellow – 4 mm, green – 8 mm, red – 16 mm and blue – blocked beams. Cross hatched sectors represent sectors that were automatically blocked by the treatment planning system to reduce dose to critical structures
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807679&req=5

Figure 0003: Example of using composite shots for the LGK PFX. To shape 50% isodose line and cover irregular target volume (meningioma) different combination of composite shots was used (see combination of eight sectors for each of eight different shots used). Different sector colors indicate different collimator size used: yellow – 4 mm, green – 8 mm, red – 16 mm and blue – blocked beams. Cross hatched sectors represent sectors that were automatically blocked by the treatment planning system to reduce dose to critical structures
Mentions: The most significant change seen in treatment planning is the ability to generate a single isocenter composed of different beam diameters. Such a composite shot allows for optimized dose distribution shape for the individual shots.[12–15] Setup of any sector combination is almost free of time penalty during patient treatment since sector position changes are done automatically within five seconds. An example of using composite shots for the LGK PFX is given in Figure 3. Similarly, an example of using dynamic shaping for the LGK PFX is given in Figure 4.

Bottom Line: Excellent agreement is also found between the dosimetric characteristics of LGK PFX and LGK 4C for the 4 and 8 mm collimators.The set up and treatment of patients on the LGK PFX is much more efficient since it is a fully automated system.The system also provides more options to generate plan with high dosimetric conformity.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, Neurological Surgery, University of Pittsburgh Cancer Institute, Pittsburgh, USA.

ABSTRACT
A new model of Leksell Gamma Knife(R) (LGK), known as Perfexion (LGK PFX), was introduced by Elekta Instrument, AB, Sweden, in 2006. This model has a radically different design from the earlier models U, B, C and 4C. Dosimetric characteristics of LGK PFX, technical differences between LGK PFX and LGK 4C, experience gained with acceptance testing and commissioning of the LGK PFX, and comparison between LGK PFX and LGK 4C are presented in this study. Excellent agreement is found between the manufacturers recommended values of absorbed dose rate, relative output factors for 4 and 8 mm collimators, coincidence of mechanical and dosimetric isocenter, FWHM for beam profiles for various collimators and those reported in the present study. Excellent agreement is also found between the dosimetric characteristics of LGK PFX and LGK 4C for the 4 and 8 mm collimators. Examples of clinical cases treated with LGK PFX and impact of LGK PFX on workflow and dosimetric conformity of treatment planning is also given. The set up and treatment of patients on the LGK PFX is much more efficient since it is a fully automated system. The system also provides more options to generate plan with high dosimetric conformity.

No MeSH data available.


Related in: MedlinePlus