Evidence map›Paper›PMID 41306071›Full record

ArticleJournal of applied clinical medical physics2025

Monte Carlo simulations of geometric deformation of Harrison-Anderson-Mick applicators used in intraoperative radiation therapy.

Benjamin Insley, Brett Bocian, Sam Beddar, Reza Reiazi, Patrick James Jensen, Rachael M Martin-Paulpeter, Joshua Scott Niedzielski, David Flint, Gabriel Oliveira Sawakuchi, Luis Augusto Perles

Abstract read
In one paragraph

Article in Journal of applied clinical medical physics, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Benjamin InsleyEmpyrean Medical Systems, Inc, Boca Raton, Florida, USA.
Brett BocianUniversity of Miami, Miami, Florida, USA.ORCID https://orcid.org/0009-0009-4033-9248
Sam BeddarDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Reza ReiaziDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Patrick James JensenAccuray Inc., Sunnyvale, California, USA.ORCID https://orcid.org/0000-0001-6984-1703
Rachael M Martin-PaulpeterDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.ORCID https://orcid.org/0000-0002-3866-6823
Joshua Scott NiedzielskiDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.ORCID https://orcid.org/0000-0002-7666-5039
David FlintDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Gabriel Oliveira SawakuchiDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Luis Augusto PerlesDepartment of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.ORCID https://orcid.org/0000-0002-5326-1998

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe Harrison-Anderson-Mick (HAM) applicator is a high-dose-rate intraoperative radiotherapy (HDR-IORT) applicator used to position Ir-192 brachytherapy sources over surgically-accessed tumor volumes or post-resection tumor beds. Because of the lack of a 3D imaging system, dwell times are optimized pre-surgery by a TG-43-based treatment planning system (TPS) that assumes a perfectly flat applicator surface surrounded by an infinite water phantom. These assumed conditions are disparate from typical treatment conditions, especially in the pelvic regions, which often involve uneven patient surfaces and superficial irradiations with little to no backscatter material. PURPOSE: Develop and validate a Monte Carlo (MC) model of HDR-IORT treatment with a HAM applicator and use this validated model to quantify inaccuracies in the dose calculations due to the simplified conditions assumed in the planning process.

methodsThe Oncentra Brachy TPS was used to optimize dwell times and calculate the delivered relative dose distribution for a 6-catheter, 8-cm HAM applicator with 0.5-cm dwell steps and 1.0-cm catheter spacing. A TOPAS (v.3.9) MC model of this treatment was then developed and validated against the TPS dose calculations. Once validated, the TOPAS applicator model was modified to calculate the difference in doses due to changes in backscatter conditions, the incorporation of the actual applicator materials, and curvature of the applicator. Dose distributions were characterized using dose to the prescription point, percent depth doses, and two-dimensional isodose curves.

resultsValidation between the MC and TPS calculations was successful within 1.5% over a depth of 5.0 cm in water. Negligible dose differences were calculated when assuming the applicator is made completely of water versus modeling all the individual applicator components. Conversely, semi-infinite phantom geometry had more than 5% loss in dose to the prescription point due to the absence of backscatter. Most severely, curvature radii in the range of 5.4 cm (shallow curvature) to 0.9 cm (steep curvature) had dose differences of 5%-25%, regardless of whether the curvature was along the catheter length or transverse to it.

conclusionsThis study quantified the changes in dose due to material and geometric differences that are currently not accounted for by the TPS. While not accounting for the material of the applicator contributes to negligibly, the presence of backscattering material can contribute up to 5%. The radius of the bending of the applicator was found to potentially have the largest impact on the dosimetry of the central plane, with deviations up to 25%.

Indexed as

BrachytherapyIridium RadioisotopesMonte Carlo MethodNeoplasmsPhantoms, ImagingRadiotherapy Planning, Computer-AssistedComputer SimulationHumansRadiotherapy DosageRadiotherapy, Intensity-ModulatedIridium-192Iridium RadioisotopesbrachytherapyHAM applicatorsIORTMonte Carlo simulationtreatment planning

Identifiers

PMID41306071
PMCPMC12658346

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.