Dose-rate tables for clinical<sup>137</sup>Cs sources sheathed in platinum

Monte Carlo calculations of the absorbed dose at various points of a brachytherapy anthropomorphic phantom are presented. The phantom walls and internal structures are made of polymethylmethacrylate and its external shape was taken from a female Alderson phantom. A complete Fletcher‐Green type applicator with the uterine tandem was fixed at the bottom of the phantom reproducing a typical geometrical configuration as that attained in a gynecological brachytherapy treatment. The dose rate produced by an array of five 137Cs CDC‐J type sources placed in the applicator colpostats and the uterine tandem was evaluated by Monte Carlo simulations using the code penelope at three points: point A, the rectum, and the bladder. The influence of the applicator in the dose rate was evaluated by comparing Monte Carlo simulations of the sources alone and the sources inserted in the applicator. Differences up to 56% in the dose may be observed for the two cases in the planes including the rectum and bladder. The results show a reduction of the dose of 15.6%, 14.0%, and 5.6% in the rectum, bladder, and point A respectively, when the applicator wall and shieldings are considered.PACS number(s): 87.53Jw, 87.53.Wz, 87.53.Vb, 87.66.Xa

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“…These sources consist of cesium bound with a low attenuation ion exchange medium of zirconium phosphate with

1.63 g / {cm}^{3}

of density 15 . The source encapsulation is 1 mm thick of a material of mass composed of 80% platinum and 20% iridium.…”

Section: Methodsmentioning

confidence: 99%

Absorbed dose calculations in a brachytherapy pelvic phantom using the Monte Carlo method

Rodríguez

deAlmeida

2002

J Applied Clin Med Phys

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“…The active material is uniformly distributed in the source active cylinder and consists of cesium bound with a low attenuation ion exchange medium of zirconium phosphate with a density of 1.63 g cm −3 . The source encapsulation material is composed of 80% platinum and 20% iridium (Karen and Breitman 1974). The source was modelled with PENELOPE as a pair of concentric cylinders with materials and dimensions as described above.…”

Section: Monte Carlo Calculationsmentioning

confidence: 99%

The photon fluence non-uniformity correction for air kerma near Cs-137 brachytherapy sources

Rodríguez

deAlmeida²

2004

Phys. Med. Biol.

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The use of brachytherapy sources in radiation oncology requires their proper calibration to guarantee the correctness of the dose delivered to the treatment volume of a patient. One of the elements to take into account in the dose calculation formalism is the non-uniformity of the photon fluence due to the beam divergence that causes a steep dose gradient near the source. The correction factors for this phenomenon have been usually evaluated by the two theories available, both of which were conceived only for point sources. This work presents the Monte Carlo assessment of the non-uniformity correction factors for a Cs-137 linear source and a Farmer-type ionization chamber. The results have clearly demonstrated that for linear sources there are some important differences among the values obtained from different calculation models, especially at short distances from the source. The use of experimental values for each specific source geometry is recommended in order to assess the non-uniformity factors for linear sources in clinical situations that require special dose calculations or when the correctness of treatment planning software is verified during the acceptance tests.

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Physics of the Use of Small Sealed Sources in Brachytherapy

Jayaraman

Lanzl

2004

Clinical Radiotherapy Physics

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Dose-rate tables for clinical¹³⁷Cs sources sheathed in platinum

Cited by 23 publications

References 9 publications

Absorbed dose calculations in a brachytherapy pelvic phantom using the Monte Carlo method

Absorbed dose calculations in a brachytherapy pelvic phantom using the Monte Carlo method

The photon fluence non-uniformity correction for air kerma near Cs-137 brachytherapy sources

Physics of the Use of Small Sealed Sources in Brachytherapy

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Dose-rate tables for clinical137Cs sources sheathed in platinum

Cited by 23 publications

References 9 publications

Absorbed dose calculations in a brachytherapy pelvic phantom using the Monte Carlo method

Absorbed dose calculations in a brachytherapy pelvic phantom using the Monte Carlo method

The photon fluence non-uniformity correction for air kerma near Cs-137 brachytherapy sources

Physics of the Use of Small Sealed Sources in Brachytherapy

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Product

Resources

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Dose-rate tables for clinical¹³⁷Cs sources sheathed in platinum