Update of the CLRP TG‐43 parameter database for low‐energy brachytherapy sources

Safigholi, Habib; Chamberland, Marc; Taylor, R. E. P.; Allen, Christian H.; Martinov, Martin P.; Rogers, D. W. O.; Thomson, Rowan M.

doi:10.1002/mp.14249

Cited by 23 publications

(70 citation statements)

References 68 publications

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“…Dose is scored in a

51 \times 51 \times 51

array of (0.05 cm) 3 voxels spanning the eye region, extending from −1.275 cm

\leq x, y \leq

1.275 cm, and from −0.075 cm

\leq z \leq

2.475 cm (voxels centered along the plaque's central axis). For voxels that overlap with the plaque, dose is scored only in the portion of the voxel not occupied by the plaque, necessitating application of egs_brachy's voxel volume correction for which

1 0^{9}

random points/cm 3 are used 16,18 …”

Section: Acquisition and Validation Methodsmentioning

confidence: 99%

Update of the CLRP eye plaque brachytherapy database for photon‐emitting sources

et al. 2021

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Purpose To update and extend the Carleton Laboratory for Radiotherapy Physics (CLRP) Eye Plaque (EP) dosimetry database for low‐energy photon‐emitting brachytherapy sources using egs_brachy, an open‐source EGSnrc application. The previous database, CLRP_EPv1, contained datasets for the Collaborative Ocular Melanoma Study (COMS) plaques (10–22 mm diameter) with 103Pd or 125I seeds (BrachyDose‐computed, 2008). The new database, CLRP_EPv2, consists of newly calculated three‐dimensional (3D) dose distributions for 17 plaques [eight COMS, five Eckert & Ziegler BEBIG, and four others representative of models used worldwide] for 103Pd, 125I, and 131Cs seeds. Acquisition and validation methods Plaque models are developed with egs_brachy, based on published/manufacturer dimensions and material data. The BEBIG plaques (modeled for the first time) are identical in dimensions to COMS plaques but differ in elemental composition and/or density. Previously benchmarked seed models are used. Eye plaques and seeds are simulated at the center of full‐scatter water phantoms, scoring in (0.05 cm)3 voxels spanning the eye for scenarios: (a) “HOMO”: simulated TG43 conditions; (b) “HETERO”: eye plaques and seeds fully modeled; (c) “HETsi” (BEBIG only): one seed is active at a time with other seed geometries present but not emitting photons (inactive); summation over all i seeds in a plaque then yields “HETsum” (includes interseed effects). For validation, doses are compared to those from CLRP_EPv1 and published data. Data format and access Data are available at https://physics.carleton.ca/clrp/eye_plaque_v2, http://doi.org/10.22215/clrp/EPv2. The data consist of 3D dose distributions (text‐based EGSnrc “3ddose” file format) and graphical presentations of the comparisons to previously published data. Potential applications The CLRP_EPv2 database provides accurate reference 3D dose distributions to advance ocular brachytherapy dose evaluations. The fully‐benchmarked eye plaque models will be freely distributed with egs_brachy, supporting adoption of model‐based dose evaluations as recommended by TG‐129, TG‐186, and TG‐221.

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“…Dose is scored in a

51 \times 51 \times 51

array of (0.05 cm) 3 voxels spanning the eye region, extending from −1.275 cm

\leq x, y \leq

1.275 cm, and from −0.075 cm

\leq z \leq

1 0^{9}

random points/cm 3 are used 16,18 …”

Section: Acquisition and Validation Methodsmentioning

confidence: 99%

Update of the CLRP eye plaque brachytherapy database for photon‐emitting sources

et al. 2021

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“…27 The plaque models and associated parameters are summarized in table 1 with pa- Table 1 rameters/dimensions defined in figure 1; the online CLRP EPv2 database contains diagrams and 131 Cs Isoray model CS-1 Rev2 ® . 18,30 For BEBIG plaques, the ophthalmic 125 I BEBIG IsoSeed ® I-125 (I25.S16) is used which is geometrically identical to the I25.S06 but has higher activity for use in ophthalmologic oncology. 18,31 The egs brachy models of these seeds were recently developed and benchmarked as part of updated 2020 CLRP TG-43v2 database.…”

Section: Iia Monte Carlo Simulations Of Eye Plaquesmentioning

confidence: 99%

“…18,30 For BEBIG plaques, the ophthalmic 125 I BEBIG IsoSeed ® I-125 (I25.S16) is used which is geometrically identical to the I25.S06 but has higher activity for use in ophthalmologic oncology. 18,31 The egs brachy models of these seeds were recently developed and benchmarked as part of updated 2020 CLRP TG-43v2 database. 18 Photons are initialized within the seeds according to the NNDC spectra 32 for 103 Pd and 131 Cs seeds, and for 125 I from the NCRP report 58, 33 all consistent with CLRP TG43v2 database.…”

Section: Iia Monte Carlo Simulations Of Eye Plaquesmentioning

confidence: 99%

“…18,31 The egs brachy models of these seeds were recently developed and benchmarked as part of updated 2020 CLRP TG-43v2 database. 18 Photons are initialized within the seeds according to the NNDC spectra 32 for 103 Pd and 131 Cs seeds, and for 125 I from the NCRP report 58, 33 all consistent with CLRP TG43v2 database. 18 The phase space source, particle recycling and other variance reduction technique features of egs brachy (that enhance simulation efficiency) are not used.…”

Section: Iia Monte Carlo Simulations Of Eye Plaquesmentioning

confidence: 99%

“…16 correction for which 10 9 random points/cm 3 is used. 16,18 Different scenarios are simulated, all with seeds fully modelled: For validation purposes, the results of the 3D MC dose calculations (.3ddose) are imported into a CLRP in-house software tool (https://physics.carleton.ca/clrp/3ddose_tools/ 3ddose-tools), e.g., to extract doses along different axes (CAX: central axis, z; transverse…”

Section: Iia Monte Carlo Simulations Of Eye Plaquesmentioning

confidence: 99%

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Update of the CLRP eye plaque brachytherapy database for photon-emitting sources

Safigholi¹,

Parsons²,

Deering³

et al. 2021

Update of the CLRP Eye Plaque Brachytherapy Database for Photon-Emitting Sources

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To update and extend the Carleton Laboratory for Radiotherapy Physics (CLRP) Eye Plaque (EP) dosimetry database for low-energy photon-emitting brachytherapy sources using egs brachy, an open-source EGSnrc application. The previous database, CLRP EPv1, contained datasets for the Collaborative Ocular Melanoma Study (COMS) plaques (10-22 mm diameter) with 103 Pd or 125 I seeds (BrachyDose-computed, 2008). The new database, CLRP EPv2, consists of newlycalculated 3D dose distributions for 17 plaques [8 COMS, 5 Eckert & Ziegler BEBIG, and 4 others representative of models used worldwide] for 103 Pd, 125 I, and 131 Cs seeds. Acquisition and Validation Methods: Plaque models are developed with egs brachy, based on published/manufacturer dimensions and material data. The BEBIG plaques (modelled for the first time) are identical in dimensions to COMS plaques but differ in elemental composition and/or density. Previously-benchmarked seed models are used. Eye plaques and seeds are simulated at the centre of fullscatter water phantoms, scoring in (0.05 cm) 3 voxels spanning the eye for scenarios: (i) 'HOMO': simulated TG43 conditions; (ii) 'HETERO': eye plaques and seeds fully modelled; (iii) 'HETsi' (BEBIG only): one seed is active at a time with other seed geometries present but not emitting photons (inactive); summation over all i seeds in a plaque then yields 'HETsum' (includes interseed effects). For validation, doses are compared to those from CLRP EPv1 and published data.

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Evaluation of dosimetric effects of metallic artifact reduction and tissue assignment on Monte Carlo dose calculations for ¹²⁵I prostate implants

et al. 2022

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Purpose: Monte Carlo (MC) simulation studies, aimed at evaluating the magnitude of tissue heterogeneity in 125 I prostate permanent seed implant brachytherapy (BT),customarily use clinical post-implant CT images to generate a virtual representation of a realistic patient model (virtual patient model).Metallic artifact reduction (MAR) techniques and tissue assignment schemes (TAS) are implemented on the post-implant CT images to mollify metallic artifacts due to BT seeds and to assign tissue types to the voxels corresponding to the bright seed spots and streaking artifacts, respectively. The objective of this study is to assess the combined influence of MAR and TAS on MC absorbed dose calculations in post-implant CT-based phantoms. The virtual patient models used for 125 I prostate implant MC absorbed dose calculations in this study are derived from the CT images of an external radiotherapy prostate patient without BT seeds and prostatic calcifications, thus averting the need to implement MAR and TAS. Methods: The geometry of the IsoSeed I25.S17plus source is validated by comparing the MC calculated results of the TG-43 parameters for the line source approximation with the TG-43U1S2 consensus data. Four MC absorbed dose calculations are performed in two virtual patient models using the egs_brachy MC code: (1) TG-43-based D w,w-TG43 , (2) D w,w-MBDC that accounts for interseed scattering and attenuation (ISA), (3) D m,m that examines ISA and tissue heterogeneity by scoring absorbed dose in tissue, and (4) D w,m that unlike D m,m scores absorbed dose in water. The MC absorbed doses (1) and ( 2) are simulated in a TG-43 patient phantom derived by assigning the densities of every voxel to 1.00 g cm −3 (water), whereas MC absorbed doses (3) and ( 4) are scored in the TG-186 patient phantom generated by mapping the mass density of each voxel to tissue according to a CT calibration curve. The MC absorbed doses calculated in this study are compared with VariSeed v8.0 calculated absorbed doses. To evaluate the dosimetric effect of MAR and TAS, the MC absorbed doses of this work (independent of MAR and TAS) are compared to the MC absorbed doses of different 125 I source models from previous studies that were calculated with different MC codes using post-implant CT-based phantoms generated by implementing MAR and TAS on post-implant CT images.

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Update of the CLRP TG‐43 parameter database for low‐energy brachytherapy sources

Cited by 23 publications

References 68 publications

Update of the CLRP eye plaque brachytherapy database for photon‐emitting sources

Update of the CLRP eye plaque brachytherapy database for photon‐emitting sources

Update of the CLRP eye plaque brachytherapy database for photon-emitting sources

Evaluation of dosimetric effects of metallic artifact reduction and tissue assignment on Monte Carlo dose calculations for ¹²⁵I prostate implants

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Update of the CLRP TG‐43 parameter database for low‐energy brachytherapy sources

Cited by 23 publications

References 68 publications

Update of the CLRP eye plaque brachytherapy database for photon‐emitting sources

Update of the CLRP eye plaque brachytherapy database for photon‐emitting sources

Update of the CLRP eye plaque brachytherapy database for photon-emitting sources

Evaluation of dosimetric effects of metallic artifact reduction and tissue assignment on Monte Carlo dose calculations for 125I prostate implants

Contact Info

Product

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Evaluation of dosimetric effects of metallic artifact reduction and tissue assignment on Monte Carlo dose calculations for ¹²⁵I prostate implants