Experimental determination of dosimetric characterization of a newly designed encapsulated interstitial brachytherapy source of ‐model Pd‐1

Nath, Ravinder; Yue, Ning J.; Roa, Eduardo

doi:10.1118/1.1510452

Cited by 9 publications

(4 citation statements)

References 5 publications

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“…Seed dimensions for the LS-1 seed [38][39][40][41][42] are the same as those used in the study by Williamson. 38 The DRAXIMAGE BrachySeed LS-1 consists of two 0.500 mm diameter aluminum silicate spheres containing a uniform distribution of 125 I. Density of the aluminum silicate is 2.81 g / cm 3 and composition by weight is 40.7% O, 21.4% Si, 16.6% Al, 11.3% Na, and 10.0% Ag 38 ͑the amount of 125 I within the spheres is assumed to be negligible͒.…”

Section: Iiia8 Draximage Brachyseed Ls-1mentioning

confidence: 99%

“…The source dimensions for the Pd-1 seed [71][72][73] are taken from the study by Chan and Prestwich. 73 The DRAXIMAGE BrachySeed Pd-1 source consists of two 0.55 mm diameter aluminum silicate spheres containing a uniform distribution of 103 Pd ͑spheres have a density of 2.53 g / cm 3 and the composition by weight 73 is 45.2% O, 23.8% Si, 18.4% Al, and 12.6% Na with a negligible amount of 103 Pd͒.…”

Section: Iiib3 Draximage Brachyseed Pd-1mentioning

confidence: 99%

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An EGSnrc Monte Carlo‐calculated database of TG‐43 parameters

2008

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Monte Carlo methods are used to calculate a complete TG-43 dosimetry parameter data set for 27 low-energy photon emitting brachytherapy sources (18 125I and 9 l03Pd). All Monte Carlo calculations are performed using the EGSnrc user-code BrachyDose. TG-43 dosimetry parameters, including dose rate constants, radial dose functions (with functional fitting parameters), and anisotropy data, are calculated with finer spatial resolution, greater range of distances, and smaller uncertainties than data currently available in the literature for many of these sources. In particular, for most of the seeds, this is the first time that anisotropy data have been tabulated at distances less than 0.5 cm from the source. These calculations employ the state-of-the-art XCOM photon cross sections, and detailed source geometries are modeled using Yegin's multigeometry package. This data set serves as a completely independent verification of the currently available dosimetry parameters calculated using other Monte Carlo codes, including MCNP and PTRAN. This report also describes the Carleton Laboratory for Radiotherapy Physics TG-43 Parameter Database, a publicly accessible web site (at http://www.physics.carleton.ca/clrp/seed_database/) through which all of the data calculated for this study can be accessed. Also available on the web site are descriptions of the methods and Monte Carlo models used in this study and comparisons of data calculated in this study with data calculated by other authors.

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Section: Iiia8 Draximage Brachyseed Ls-1mentioning

confidence: 99%

Section: Iiib3 Draximage Brachyseed Pd-1mentioning

confidence: 99%

An EGSnrc Monte Carlo‐calculated database of TG‐43 parameters

2008

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“…(1,2) The TG-43 protocols have been extensively used to determine the dosimetric characteristics of various source types and models with a Corresponding author: Ali S. Meigooni, University of Kentucky, Department of Radiation Medicine, Lexington, KY, U.S.A.; phone: 859-323-6487; fax: 859-257-1211; email: alimeig@email.uky.edu active lengths of 1.0 cm or less. (3)(4)(5)(6)(7)(8)(9) The original TG-43 protocol, introduced in 1995, was based on recommendations of the Interstitial Collaborative Working Group (10) and provided limited published dosimetric data. Their data included 125 I [models 6711 and 6702 (Amersham/ Oncura, Plymouth Meeting, PA)], 103 Pd [model 200 (Theragenics Corporation, Norcross, GA)], and 192 Ir (Best Industries, Springfield, VA) sources.…”

Section: Introductionmentioning

confidence: 99%

Cylindrical coordinate‐based TG‐43U1 parameters for dose calculation around elongated brachytherapy sources

Awan

2008

J Applied Clin Med Phys

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In 2001, the use of cylindrical coordinates was demonstrated to be more suitable than was the use of polar coordinates for accurate computer calculations during treatment planning for normalI192r intravascular brachytherapy sources. In the present work, we investigated the applicability of cylindrical coordinate–based TG‐43U1 parameters for dosimetric evaluation and dose calculations for RadioCoil 103Pd sources (RadioMed Corporation, Tyngsboro, MA) 1.0‐cm to 6.0‐cm long. For brevity, only the results for sources 1.0‐cm, 3.0‐cm, and 5.0‐cm long are presented here. Dosimetric characteristics of RadioCoil 103Pd sources were calculated in liquid water using the Monte Carlo simulation technique. To demonstrate the suitability of this methodology, the Monte Carlo–simulated dose profiles for a RadioCoil 103Pd source 5.0‐cm long at radial distances of 0.5 cm, 0.9 cm, and 1.25 cm were compared with calculated data using TG‐43U1 parameters in the polar and cylindrical coordinate systems. In addition, we also used a source 1.0‐cm long parameterized using cylindrical coordinates to investigate the application of a linear segmented source (LSS) model originally introduced by our group. The results indicate that, for dose calculation around elongated brachytherapy sources, cylindrical coordinate–based TG‐43U1 parameters more accurately represent the dose distribution around an elongated source than the polar coordinate–based parameters. In addition, the LSS model, in conjunction with the cylindrical coordinate–based parameters for a source 1.0‐cm long, can be used to replicate the dose distribution around any integral source length. This process eliminates the need to collect and enter data for multiple source lengths into treatment planning systems.PACS number: 87.66.Jj

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“…[3][4][5] Due to this fact, several investigators have presented F͑r , ͒, mainly for the TG-43U1 recommended minimal radial distances. [6][7][8] However, for elongated photon emitting brachytherapy sources ͑active length Ͼ1.0 cm͒ such as RadioCoil™ 103 Pd 9 and 137 Cs tubes, the variation of the 2D anisotropy function with radial distance has not been evaluated.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of TG‐43 recommended 2D‐anisotropy function for elongated brachytherapy sources

et al. 2006

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The original and updated protocols recommended by Task Group 43 from the American Association of Physicists in Medicine (i.e., TG-43 and TG-43U1, respectively), have been introduced to unify brachytherapy source dosimetry around the world. Both of these protocols are based on experiences with sources less than 1.0 cm in length. TG-43U1 recommends that for 103Pd sources, 2D anisotropy function F(r, theta), should be tabulated at a minimum for radial distances of 0.5, 1.0, 2.0, 3.0, and 5.0 cm. Anisotropy functions defined in these protocols are only valid when the point of calculation does not fall on the active length of the source. However, for elongated brachytherapy sources (active length >1 cm), some of the calculation points with r < 1/2 active length and small theta may fall on the source itself and there is no clear recommendation to handle this situation. In addition, the linear interpolation technique recommended by TG-43U1 is found to be valid for seed types of sources as the difference between F(r, theta) for two consecutive radii is <10%. However, in the present investigations it has been found that values of F(r, 5 degrees) for a 5 cm long RadioCoil 103Pd source at radial distances of 2.5, 3.0, and 4.0 cm were 2.95, 1.74, and 1.19, respectively, with differences up to about a factor of 3. Therefore, the validity of the linear interpolation technique for an elongated brachytherapy source with such a large variation in F(r, theta) needs to be investigated. In this project, application of the TG-43U1 formalism for dose calculation around an elongated RadioCoil 103Pd brachytherapy source has been investigated. In addition, the linear interpolation techniques as described in TG-43U1 for seed type sources have been evaluated for a 5.0 cm long RadioCoil 103Pd brachytherapy source. Application of a polynomial fit to F(r, theta) has also been investigated as an alternate approach to the linear interpolation technique. The results of these investigations indicate that the TG-43U1 formalism can be extended for elongated brachytherapy sources, if the two-dimensional (2D) anisotropy function is tabulated at a minimum for radial distances of 0.2, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 cm, L/2, and L/2 +/- 0.2 cm. Moreover, with the addition of recommended radial distances for 2D anisotropy functions, the linear interpolation technique more closely replicates Monte Carlo simulated data than a polynomial fit.

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Experimental determination of dosimetric characterization of a newly designed encapsulated interstitial brachytherapy source of ‐model Pd‐1

Cited by 9 publications

References 5 publications

An EGSnrc Monte Carlo‐calculated database of TG‐43 parameters

An EGSnrc Monte Carlo‐calculated database of TG‐43 parameters

Cylindrical coordinate‐based TG‐43U1 parameters for dose calculation around elongated brachytherapy sources

Evaluation of TG‐43 recommended 2D‐anisotropy function for elongated brachytherapy sources

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