A generic high-dose rate<sup>192</sup>Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism

Ballester, F.; Tedgren, Åsa Carlsson; Granero, Domingo; Haworth, Annette; Mourtada, Firas; Fonseca, Gabriel Paiva; Zourari, K.; Papagiannis, Panagiotis; Rivard, Mark J.; Siebert, Frank‐André; Sloboda, Ron S.; Smith, R. L.; Thomson, Rowan M.; Verhaegen, Frank; Vijande, J.; Ma, Y.; Beaulieu, Luc

doi:10.1118/1.4921020

Cited by 67 publications

(62 citation statements)

References 48 publications

(71 reference statements)

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“…Difference between IRAsource model and other similar

^{192} Ir

‐HDR sources in common use 13 , 14 , 15 , 16 , 17 is listed in Table 1. All HDR sources have similar active length and active core diameter and are all encapsulated in stainless steel tubes.…”

Section: Methodsmentioning

confidence: 99%

Gafchromic film dosimetry of a new HDR brachytherapy source

Ayoobian

Asl

Poorbaygi³

et al. 2016

J Applied Clin Med Phys

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High‐dose‐rate (HDR) brachytherapy is a popular modality for treating cancers of the prostate, cervix, endometrium, breast, skin, bronchus, esophagus, and head and neck as well as soft‐tissue sarcomas. Because of different source designs and licensing issues, there is a need for specific dosimetry dataset for each HDR source model. The main objective of the present work is to measure 2D relative dose distribution around a new prototype 192Ir source, referred to as IRAsource‐HDR, in PMMA phantom in the framework of AAPM TG‐43 and TG‐55 recommendations for radial distances of 0.5 cm to 4 cm. Radiochromic films (RCFs) Gafchromic EBT and HD‐810 were used for measurements. The dose rate constant, Λ, of the source was determined to be 1.084±4.6%,1.129±4.4%, and 1.112±0.8% cGyh−1normalU−1 using EBTRCF, HD‐810 RCF, and Monte Carlo (MC) simulation, respectively. The results obtained in this study are in good agreement with previously published data for HDR interstitial 192Ir‐HDR sources with a maximum discrepancy of ±4.5%. An acceptable agreement (within ±2%) between MC calculations and RCFs measurements showed that HD‐810 RCF dosimetry is as good as EBTRCF, within HDR brachytherapy, and justifies the use of specific data for this new source. These data could be used as a benchmark for dose calculations in the conventional brachytherapy treatment planning systems.PACS number(s): 87.56.bg

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“…Difference between IRAsource model and other similar

^{192} Ir

‐HDR sources in common use 13 , 14 , 15 , 16 , 17 is listed in Table 1. All HDR sources have similar active length and active core diameter and are all encapsulated in stainless steel tubes.…”

Section: Methodsmentioning

confidence: 99%

Gafchromic film dosimetry of a new HDR brachytherapy source

Ayoobian

Asl

Poorbaygi³

et al. 2016

J Applied Clin Med Phys

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“…This balance has been optimized for 192 Ir sources in the current software, and cannot be modified by the user. A potential issue with angular discretization methods is the presence of ‘ray-line’ artifacts in the dose distribution, however these have been essentially eliminated in AcurosBV [16]. Early versions of the software reported only dose to water for photon transport in full medium, D w,m ; however, since 2013, the user has been offered a choice between D m,m and D w,m [8].…”

Section: Commercial Treatment Planning Systems Incorporating Model-bamentioning

confidence: 99%

“…Parameters in the calculation that influence accuracy and over which the user is given limited control include the numbers of photon transport directions (coincident with the collapsed cone axes) for once- and multiply-scattered photons. As for AcurosBV, angular discretization (in the form of photon transport directions) brings with it the possibility of ‘ray-line’ artifacts, which for ACE are comparatively more pronounced, but of limited clinical concern [16]. A comprehensive description of the implementation can be found in a recent publication dedicated to the topic [9].…”

Section: Commercial Treatment Planning Systems Incorporating Model-bamentioning

confidence: 99%

“…When the TPS incorporates a MBDCA, additional algorithm-specific tasks need to be done as recommended in the AAPM/ESTRO/ABG TG-186 report [7]. Recently, a web-based MBDCA commissioning Registry was opened to support physicists and dosimetrists in performing these additional tasks, as reported at the 2016 World Congress of Brachytherapy [28] by the joint AAPM/ESTRO/ABG working group on MBDCAs in brachytherapy [16, 29]. In brief, the Registry enables an MBDCA user to compare a locally calculated dose distribution with a reference dose distribution generated, using MC simulation, for a series of well-defined ‘test plans’.…”

Section: Commercial Treatment Planning Systems Incorporating Model-bamentioning

confidence: 99%

“…For ACE calculations, the applicator was placed in a 30 cm 3 virtual water box and the two grooves on the outside of the applicator were filled with air. Uncertainties for the TG-43 and ACE calculations were estimated to be 3.4% and 5%, respectively [13, 16, 46]. …”

Section: Experience Using Commercial Model-based Dose Calculation Algmentioning

confidence: 99%

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A brief look at model-based dose calculation principles, practicalities, and promise

Sloboda¹,

Morrison²,

Cawston-Grant³

et al. 2017

jcb

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Model-based dose calculation algorithms (MBDCAs) have recently emerged as potential successors to the highly practical, but sometimes inaccurate TG-43 formalism for brachytherapy treatment planning. So named for their capacity to more accurately calculate dose deposition in a patient using information from medical images, these approaches to solve the linear Boltzmann radiation transport equation include point kernel superposition, the discrete ordinates method, and Monte Carlo simulation. In this overview, we describe three MBDCAs that are commercially available at the present time, and identify guidance from professional societies and the broader peer-reviewed literature intended to facilitate their safe and appropriate use. We also highlight several important considerations to keep in mind when introducing an MBDCA into clinical practice, and look briefly at early applications reported in the literature and selected from our own ongoing work. The enhanced dose calculation accuracy offered by a MBDCA comes at the additional cost of modelling the geometry and material composition of the patient in treatment position (as determined from imaging), and the treatment applicator (as characterized by the vendor). The adequacy of these inputs and of the radiation source model, which needs to be assessed for each treatment site, treatment technique, and radiation source type, determines the accuracy of the resultant dose calculations. Although new challenges associated with their familiarization, commissioning, clinical implementation, and quality assurance exist, MBDCAs clearly afford an opportunity to improve brachytherapy practice, particularly for low-energy sources.

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Experimental verification of Advanced Collapsed‐cone Engine for use with a multichannel vaginal cylinder applicator

Cawston-Grant

Morrison

Menon

et al. 2017

J Applied Clin Med Phys

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Model‐based dose calculation algorithms have recently been incorporated into brachytherapy treatment planning systems, and their introduction requires critical evaluation before clinical implementation. Here, we present an experimental evaluation of Oncentra® Brachy Advanced Collapsed‐cone Engine (ACE) for a multichannel vaginal cylinder (MCVC) applicator using radiochromic film. A uniform dose of 500 cGy was specified to the surface of the MCVC using the TG‐43 dose formalism under two conditions: (a) with only the central channel loaded or (b) only the peripheral channels loaded. Film measurements were made at the applicator surface and compared to the doses calculated using TG‐43, standard accuracy ACE (sACE), and high accuracy ACE (hACE). When the central channel of the applicator was used, the film measurements showed a dose increase of (11 ± 8)% (k = 2) above the two outer grooves on the applicator surface. This increase in dose was confirmed with the hACE calculations, but was not confirmed with the sACE calculations at the applicator surface. When the peripheral channels were used, a periodic azimuthal variation in measured dose was observed around the applicator. The sACE and hACE calculations confirmed this variation and agreed within 1% of each other at the applicator surface. Additionally for the film measurements with the central channel used, a baseline dose variation of (10 ± 4)% (k = 2) of the mean dose was observed azimuthally around the applicator surface, which can be explained by offset source positioning in the central channel.

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A generic high-dose rate¹⁹²Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism

Cited by 67 publications

References 48 publications

Gafchromic film dosimetry of a new HDR brachytherapy source

Gafchromic film dosimetry of a new HDR brachytherapy source

A brief look at model-based dose calculation principles, practicalities, and promise

Experimental verification of Advanced Collapsed‐cone Engine for use with a multichannel vaginal cylinder applicator

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A generic high-dose rate192Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism

Cited by 67 publications

References 48 publications

Gafchromic film dosimetry of a new HDR brachytherapy source

Gafchromic film dosimetry of a new HDR brachytherapy source

A brief look at model-based dose calculation principles, practicalities, and promise

Experimental verification of Advanced Collapsed‐cone Engine for use with a multichannel vaginal cylinder applicator

Contact Info

Product

Resources

About

A generic high-dose rate¹⁹²Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism