Application of the Monte Carlo integration (MCI) method for calculation of the anisotropy of brachytherapy sources

Baltas, Dimos; Giannouli, Stavroula; Garbi, Anastasia; Diakonos, F. Κ.; Geramani, Konstantina; Ioannidis, Georgios; Tsalpatouros, A.; Uzunoglu, N.K.; Kolotas, Christos; Zamboglou, Nikolaos

doi:10.1088/0031-9155/43/6/029

Cited by 21 publications

(15 citation statements)

References 30 publications

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“…Additional MC calculations showed that this is due to the fact that in the simulation of Wang and Sloboda the extension of the nickel/ titanium wire was modeled as only 3 mm long, while in our simulation the wire was extended to its actual length. This observation is in agreement with Baltas et al 13 who investigated the influence of the source cable on the anisotropy calculations of the microSelectron HDR brachytherapy source.…”

Section: Anisotropy Functionssupporting

confidence: 92%

A Monte Carlo investigation of the dosimetric characteristics of the VariSource 192Ir high dose rate brachytherapy source

Karaiskos¹,

Angelopoulos²,

Baras³

et al. 1999

Med. Phys.

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An analytical Monte Carlo simulation code, incorporating in detail source construction and dimensions, was used to investigate the dosimetric characteristics of the VariSource 192Ir high dose rate brachytherapy source. Dose-rate constant, radial dose functions, and anisotropy functions, utilized in the AAPM Task Group 43 dose estimation formalism, were calculated with the source centered in a spherical water phantom of 30 cm in diameter. The results, which are in agreement with the corresponding data available in the literature, are compared to those obtained in our previous study for the widely used microSelectron 192Ir high dose-rate brachytherapy source. The dose-rate constant was found to be equal to 1.043 +/- 0.005 cGy h(-1) U(-1) for the VariSource, compared to a value of 1.116 +/- 0.006 cGy h(-1) U(-1) calculated for the microSelectron. Significant differences in the anisotropy of the two sources are observed only for polar angles close to their long axis and are due to their different dimensions.

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Section: Anisotropy Functionssupporting

confidence: 92%

A Monte Carlo investigation of the dosimetric characteristics of the VariSource 192Ir high dose rate brachytherapy source

Karaiskos¹,

Angelopoulos²,

Baras³

et al. 1999

Med. Phys.

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“…Two different MC simulation codes 20,11,16,[21][22][23] as well as the dose point kernel method 24 -27 were used for dose rate calculations of this study. The dose point kernel method, based on the experimentally derived Loevinger's equation that provides a reasonable evaluation of dose rate distribution at distances of clinical interest, was utilized for point as well as real cylindrical sources ͑using the MC integration method͒ 28 since it presents the advantage of extreme computational efficiency.…”

Section: Monte Carlo Calculationsmentioning

confidence: 99%

Beta versus gamma dosimetry close to Ir‐192 brachytherapy sources

et al. 2001

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The relative importance of the dose rate component owing to the beta spectrum emitted by 192Ir brachytherapy sources at the short radial distances of interest in intravascular and endobronchial applications is investigated. Separate dosimetric calculations, using Monte Carlo simulations, were performed for the gamma and beta dose rate components of an 192Ir ideal point source as well as real 192Ir source designs used in clinical practice including wire and seed sources and both Nucletron and Varian, old and new, high dose rate (HDR) source designs. A significant dose rate enhancement due to the beta spectrum emitted by 192Ir, greater than 50% for radial distances r<2 mm, was observed for an ideal point source. For real source designs, however, the magnitude of this enhancement was found to depend strongly on the sources' geometric as well as compositional details of the active core and encapsulation. A detectable effect was found for the majority of the investigated sources at radial distances less than 1 mm, but overall findings suggest that the contribution of beta particles is not significant in 192Ir clinical intravascular applications that are currently carried out. However, since treatment of vessels with smaller diameters, in the future, may lead to the development of 192Ir sources and catheters of reduced diameters, the potential effect of the beta spectrum in terms of dose enhancement to tissues in close proximity to 192Ir sources should not be ignored.

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“…͑1͒. 11 The radioactive material was assumed to be uniformly distributed within the active core of the investigated source ((rЈ) ϭ1) and a large number N of random points were uniformly generated. The integral of Eq.…”

Section: B Calculation Of Geometry Factorsmentioning

confidence: 99%

Limitations of the point and line source approximations for the determination of geometry factors around brachytherapy sources

et al. 2000

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Geometry factors were calculated around commercially available pellets and elongated brachytherapy sources taking into account their actual active core geometries. These calculations were compared with corresponding ones derived using the point and line source approximations commonly used for the determination of geometry factors, as proposed by AAPM Task Group 43. The point source approximation was found to be efficient for the determination of geometry factors around single active pellets, even at radial distances very close to the source. It is also valid for the determination of geometry factors at radial distances r>2L from elongated brachytherapy sources of length L. For smaller radial distances, however, this approximation introduces significant errors, >50%, around elongated source designs, thus being unacceptable for the determination of geometry factors in this case. The line source approximation was found to accurately reproduce geometry factors around elongated brachytherapy source designs. Errors greater than 3%, due to the fact that the line source approximation ignores the radial dimension d of the source, are observed only at radial distances very close to the source (r< or =L/2), at polar angles far away from their transverse bisectors. These errors depend on the ratio d/L and increase as this ratio increases.

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Application of the Monte Carlo integration (MCI) method for calculation of the anisotropy of brachytherapy sources

Cited by 21 publications

References 30 publications

A Monte Carlo investigation of the dosimetric characteristics of the VariSource 192Ir high dose rate brachytherapy source

A Monte Carlo investigation of the dosimetric characteristics of the VariSource 192Ir high dose rate brachytherapy source

Beta versus gamma dosimetry close to Ir‐192 brachytherapy sources

Limitations of the point and line source approximations for the determination of geometry factors around brachytherapy sources

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