Monte Carlo calculation of depth doses for small field of CyberKnife

Tokihiro Yamamoto; Teruki Teshima; Satoshi Miyajima; Masao Matsumoto; Hiroya Shiomi; Takehiro Inoue; Toshihiko Inoue; Hideo Hirayama

Monte Carlo calculation of depth doses for small field of CyberKnife

Tokihiro Yamamoto, Teruki Teshima, Satoshi Miyajima, Masao Matsumoto, Hiroya Shiomi, Takehiro Inoue, Toshihiko Inoue, Hideo Hirayama

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Purpose: A Monte Carlo (MC) model of CyberKnife was developed as a quality assurance tool. The percentage depth dose (%dd) was verified by using this model. Materials and Methods: An MC model was developed with Electron Gamma Shower version 4 (EGS4) in two steps: (1) a model of the CyberKnife treatment head and (2) a model of the collimator and phantom. The bremsstrahlung spectrum was calculated using the first model, and this spectrum was then used to calculate %dds with the second model. The calculated %dds for a large field (60 mmφ) and three small fields (30, 15, and 5 mmφ) were compared with those measured with a diamond detector. Results and Discussion: The MC-calculated and measured %dd-curves for the 60 mmφ field were in excellent agreement (<1.85%), thus confirming the validity of the model. Discrepancies between the calculated and measured %dd-curves increased with decreasing field size, with considerable discrepancy (11.62%) for the 5 mmφ field due to lateral electron disequilibrium. Accurate dose can be determined with MC even in small fields. Conclusion: The MC technique can provide reliable standard data for accurate dose delivery with high-technology radiotherapies using small beams.

Original language	English (US)
Pages (from-to)	305-310
Number of pages	6
Journal	Radiation Medicine - Medical Imaging and Radiation Oncology
Volume	20
Issue number	6
State	Published - Nov 2002
Externally published	Yes

Keywords

CyberKnife
Diamond detector
EGS4
Monte Carlo
Small field dosimetry

ASJC Scopus subject areas

Radiology Nuclear Medicine and imaging
Radiation

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Monte Carlo calculation of depth doses for small field of CyberKnife. / Yamamoto, Tokihiro; Teshima, Teruki; Miyajima, Satoshi; Matsumoto, Masao; Shiomi, Hiroya; Inoue, Takehiro; Inoue, Toshihiko; Hirayama, Hideo.

In: Radiation Medicine - Medical Imaging and Radiation Oncology, Vol. 20, No. 6, 11.2002, p. 305-310.

Research output: Contribution to journal › Article › peer-review

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abstract = "Purpose: A Monte Carlo (MC) model of CyberKnife was developed as a quality assurance tool. The percentage depth dose (%dd) was verified by using this model. Materials and Methods: An MC model was developed with Electron Gamma Shower version 4 (EGS4) in two steps: (1) a model of the CyberKnife treatment head and (2) a model of the collimator and phantom. The bremsstrahlung spectrum was calculated using the first model, and this spectrum was then used to calculate %dds with the second model. The calculated %dds for a large field (60 mmφ) and three small fields (30, 15, and 5 mmφ) were compared with those measured with a diamond detector. Results and Discussion: The MC-calculated and measured %dd-curves for the 60 mmφ field were in excellent agreement (<1.85%), thus confirming the validity of the model. Discrepancies between the calculated and measured %dd-curves increased with decreasing field size, with considerable discrepancy (11.62%) for the 5 mmφ field due to lateral electron disequilibrium. Accurate dose can be determined with MC even in small fields. Conclusion: The MC technique can provide reliable standard data for accurate dose delivery with high-technology radiotherapies using small beams.",

keywords = "CyberKnife, Diamond detector, EGS4, Monte Carlo, Small field dosimetry",

author = "Tokihiro Yamamoto and Teruki Teshima and Satoshi Miyajima and Masao Matsumoto and Hiroya Shiomi and Takehiro Inoue and Toshihiko Inoue and Hideo Hirayama",

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T1 - Monte Carlo calculation of depth doses for small field of CyberKnife

AU - Yamamoto, Tokihiro

AU - Teshima, Teruki

AU - Miyajima, Satoshi

AU - Matsumoto, Masao

AU - Shiomi, Hiroya

AU - Inoue, Takehiro

AU - Inoue, Toshihiko

AU - Hirayama, Hideo

PY - 2002/11

Y1 - 2002/11

N2 - Purpose: A Monte Carlo (MC) model of CyberKnife was developed as a quality assurance tool. The percentage depth dose (%dd) was verified by using this model. Materials and Methods: An MC model was developed with Electron Gamma Shower version 4 (EGS4) in two steps: (1) a model of the CyberKnife treatment head and (2) a model of the collimator and phantom. The bremsstrahlung spectrum was calculated using the first model, and this spectrum was then used to calculate %dds with the second model. The calculated %dds for a large field (60 mmφ) and three small fields (30, 15, and 5 mmφ) were compared with those measured with a diamond detector. Results and Discussion: The MC-calculated and measured %dd-curves for the 60 mmφ field were in excellent agreement (<1.85%), thus confirming the validity of the model. Discrepancies between the calculated and measured %dd-curves increased with decreasing field size, with considerable discrepancy (11.62%) for the 5 mmφ field due to lateral electron disequilibrium. Accurate dose can be determined with MC even in small fields. Conclusion: The MC technique can provide reliable standard data for accurate dose delivery with high-technology radiotherapies using small beams.

AB - Purpose: A Monte Carlo (MC) model of CyberKnife was developed as a quality assurance tool. The percentage depth dose (%dd) was verified by using this model. Materials and Methods: An MC model was developed with Electron Gamma Shower version 4 (EGS4) in two steps: (1) a model of the CyberKnife treatment head and (2) a model of the collimator and phantom. The bremsstrahlung spectrum was calculated using the first model, and this spectrum was then used to calculate %dds with the second model. The calculated %dds for a large field (60 mmφ) and three small fields (30, 15, and 5 mmφ) were compared with those measured with a diamond detector. Results and Discussion: The MC-calculated and measured %dd-curves for the 60 mmφ field were in excellent agreement (<1.85%), thus confirming the validity of the model. Discrepancies between the calculated and measured %dd-curves increased with decreasing field size, with considerable discrepancy (11.62%) for the 5 mmφ field due to lateral electron disequilibrium. Accurate dose can be determined with MC even in small fields. Conclusion: The MC technique can provide reliable standard data for accurate dose delivery with high-technology radiotherapies using small beams.

KW - CyberKnife

KW - Diamond detector

KW - EGS4

KW - Monte Carlo

KW - Small field dosimetry

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Monte Carlo calculation of depth doses for small field of CyberKnife

Abstract

Keywords

ASJC Scopus subject areas

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