Initial evaluation of Advanced Collapsed cone Engine dose calculations in water medium for I‐125 seeds and <scp>COMS</scp> eye plaques

Morrison, Heather; Menon, Geetha; Larocque, Matthew; Veelen, Bob van; Niatsetski, Yury; Weis, Ezekiel; Sloboda, Ron S.

doi:10.1002/mp.12776

Cited by 6 publications

(69 citation statements)

References 46 publications

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“…Differences along the plaque CAX ranged from [+0.7, +7.8%], shown in Fig. , following a trend similar to that observed for the plaque in water examined in previous work (the largest differences were close to the plaque surface and decreased with distance from the plaque) …”

Section: Resultssupporting

confidence: 84%

“…When separating the effects of the plaque materials (seen as the high‐ and low‐dose streaks in the penumbra of the plaque, and examined thoroughly in previous work) from those of the heterogeneous tissue materials (

{false[Δ_{italictissue} false]}_{M C N P 6}^{italicACE}

), the differences in the plaque penumbra are in the interval [−9%, +17%] and the differences at the tissue interfaces throughout the eye are in the range [−19%, +16%].

{false[Δ_{italictissue} false]}_{M C N P 6}^{italicACE}

in the central slice of the eye phantom is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The 16 mm COMS plaque model was incorporated into the OcB applicator library via processing of three‐dimensional (3D) CAD drawings of the plaque and Silastic insert based on dimensions, seed/slot coordinates, and material properties given in the TG‐129 report . Details of the source and applicator modeling and incorporation into both MCNP6 and OcB, as well as the benchmarking of the MC models and the evaluation of the accuracy of ACE for a single source in water and three COMS plaques in water, are provided in our previous work …”

Section: Methodsmentioning

confidence: 99%

“…Although larger differences in the form of ray artifacts were visible beyond ~1.5 cm from the source, global percent differences (for which r ref is at 1 cm from the source on the transverse axis) are quite small (<0.75%). From the examination of plaque dosimetry in water, expected differences when moving forward to more complex scenarios are probable at the penumbral edges of the plaque, though for most parts of the eye, the differences were found to be within the uncertainty of ACE calculations (~5%) . Depending on the position of the plaque relative to the optic nerve, optic disk, and fovea, these sensitive structures could be located in the plaque penumbra, and therefore, the accuracy of ACE in these regions would be of concern and will warrant careful examination.…”

Section: Methodsmentioning

confidence: 99%

“…This research version incorporates the same ACE algorithm as the commercially available version (v4.5), and in addition, provides the user with flexibility to adjust certain calculation parameters which are fixed in the commercial version (number of transport directions, dose calculation grid size, option to account for source decay). The accuracy of the I‐125 source modeling and three sizes of COMS plaques in water medium were assessed in our previous work …”

Section: Introductionmentioning

confidence: 99%

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Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I‐125 seeds

et al. 2018

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Overall, ACE dosimetry agreed well with MC in the tumor volume and along the plaque CAX for the two heterogeneous tissue scenarios, indicating that ACE could potentially be used for clinical ocular brachytherapy dosimetry. In general, ACE data matched the fully heterogeneous MC data more closely than water-based data, even in regions where the ACE accuracy was relatively low. However, depending on the plaque position, doses to critical structures near the plaque penumbra or at tissue interfaces were less accurate, indicating that improvements may be necessary. More extensive knowledge of eye tissue compositions is still required.

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Section: Resultssupporting

confidence: 84%

{false[Δ_{italictissue} false]}_{M C N P 6}^{italicACE}

), the differences in the plaque penumbra are in the interval [−9%, +17%] and the differences at the tissue interfaces throughout the eye are in the range [−19%, +16%].

{false[Δ_{italictissue} false]}_{M C N P 6}^{italicACE}

in the central slice of the eye phantom is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I‐125 seeds

et al. 2018

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AAPM recommendations on medical physics practices for ocular plaque brachytherapy: Report of task group 221

et al. 2020

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The American Association of Physicists in Medicine (AAPM) formed Task Group 221 (TG-221) to discuss a generalized commissioning process, quality management considerations, and clinical physics practice standards for ocular plaque brachytherapy. The purpose of this report is also, in part, to aid the clinician to implement recommendations of the AAPM TG-129 report, which placed emphasis on dosimetric considerations for ocular brachytherapy applicators used in the Collaborative Ocular Melanoma Study (COMS). This report is intended to assist medical physicists in establishing a new ocular brachytherapy program and, for existing programs, in reviewing and updating clinical practices. The report scope includes photon-and beta-emitting sources and source:applicator combinations. Dosimetric studies for photon and beta sources are reviewed to summarize the salient issues and provide references for additional study. The components of an ocular plaque brachytherapy quality management program are discussed, including radiation safety considerations, source calibration methodology, applicator commissioning, imaging quality assurance tests for treatment planning, treatment planning strategies, and treatment planning system commissioning. Finally, specific guidelines for commissioning an ocular plaque brachytherapy program, clinical physics practice standards in ocular plaque brachytherapy, and other areas reflecting the need for specialized treatment planning systems, measurement phantoms, and detectors (among other topics) to support the clinical practice of ocular brachytherapy are presented. Expected future advances and developments for ocular brachytherapy are discussed.

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Generation and comparison of 3D dosimetric reference datasets for COMS eye plaque brachytherapy using model‐based dose calculations

Fletcher,

Ballester,

Beaulieu

et al. 2023

Medical Physics

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PurposeA joint Working Group of the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) was created to aid in the transition from the AAPM TG‐43 dose calculation formalism, the current standard, to model‐based dose calculations. This work establishes the first test cases for low‐energy photon‐emitting brachytherapy using model‐based dose calculation algorithms (MBDCAs).Acquisition and Validation MethodsFive test cases are developed: (1) a single model 6711 125I brachytherapy seed in water, 13 seeds (2) individually and (3) in combination in water, (4) the full Collaborative Ocular Melanoma Study (COMS) 16 mm eye plaque in water, and (5) the full plaque in a realistic eye phantom. Calculations are done with four Monte Carlo (MC) codes and a research version of a commercial treatment planning system (TPS). For all test cases, local agreement of MC codes was within ∼2.5% and global agreement was ∼2% (4% for test case 5). MC agreement was within expected uncertainties. Local agreement of TPS with MC was within 5% for test case 1 and ∼20% for test cases 4 and 5, and global agreement was within 0.4% for test case 1 and 10% for test cases 4 and 5.Data Format and Usage NotesDose distributions for each set of MC and TPS calculations are available online (https://doi.org/10.52519/00005) along with input files and all other information necessary to repeat the calculations.Potential ApplicationsThese data can be used to support commissioning of MBDCAs for low‐energy brachytherapy as recommended by TGs 186 and 221 and AAPM Report 372. This work additionally lays out a sample framework for the development of test cases that can be extended to other applications beyond eye plaque brachytherapy.

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Initial evaluation of Advanced Collapsed cone Engine dose calculations in water medium for I‐125 seeds and COMS eye plaques

Abstract: Overall, good agreement was found between ACE and MC dose calculations for a single I-125 seed and in front of the COMS plaques in water. More complex scenarios need to be investigated to determine how well ACE handles heterogeneous patient materials.

Cited by 6 publications

References 46 publications

Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I‐125 seeds

Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I‐125 seeds

AAPM recommendations on medical physics practices for ocular plaque brachytherapy: Report of task group 221

Generation and comparison of 3D dosimetric reference datasets for COMS eye plaque brachytherapy using model‐based dose calculations

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