A retrospective dosimetric comparison of TG43 and a commercially available MBDCA for an APBI brachytherapy patient cohort

Zourari, K.; Major, Tibor; Herein, András; Peppa, Vasiliki; Polgár, Csaba; Papagiannis, Panagiotis

doi:10.1016/j.ejmp.2015.05.010

Cited by 30 publications

(13 citation statements)

References 22 publications

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“…This can be explained by the fact that this parameter was always located in a region of higher gradient of the DVH, where small deviations cause a major change of parameter value. These results agree with the findings of other groups who also reported an increase in deviations for V 150 compared to the other volume parameters [5,8]. However, V 150 and V 100 are of little clinical relevance in brachytherapy for liver metastases, because there is no demand for a homogeneous dose profile in the target volumes.…”

Section: Target Coveragesupporting

confidence: 91%

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The dosimetric impact of replacing the TG-43 algorithm by model based dose calculation for liver brachytherapy

et al. 2020

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Purpose: To compare treatment plans for interstitial high dose rate (HDR) liver brachytherapy with 192 Ir calculated according to current-standard TG-43U1 protocol with model-based dose calculation following TG-186 protocol. Methods: We retrospectively evaluated dose volume histogram (DVH) parameters for liver, organs at risk (OARs) and clinical target volumes (CTVs) of 20 patient cases diagnosed with hepatocellular carcinoma (HCC) or metastatic colorectal cancer (mCRC). Dose calculations on a homogeneous water geometry (TG-43U1 surrogate) and on a computed tomography (CT) based geometry (TG-186) were performed using Monte Carlo (MC) simulations. The CTs were segmented based on a combination of assigning TG-186 recommended tissues to fixed Hounsfield Unit (HU) ranges and using organ contours delineated by physicians. For the liver, V 5Gy and V 10Gy were analysed, and for OARs the dose to 1 cubic centimeter (D 1cc ). Target coverage was assessed by calculating V 150 , V 100 , V 95 and V 90 as well as D 95 and D 90 . For every DVH parameter, median, minimum and maximum values of the deviations of TG-186 from TG-43U1 were analysed. Results: TG-186-calculated dose was found to be on average lower than dose calculated with TG-43U1. The deviation of highest magnitude for liver parameters was -6.2% of the total liver volume. For OARs, the deviations were all smaller than or equal to -0.5 Gy. Target coverage deviations were as high as -1.5% of the total CTV volume and -3.5% of the prescribed dose. Conclusions: In this study we found that TG-43U1 overestimates dose to liver tissue compared to TG-186. This finding may be of clinical importance for cases where dose to the whole liver is the limiting factor.

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Section: Target Coveragesupporting

confidence: 91%

“…Other groups also suggested a correlation between deviations from TG-43U1 and photon travel distance path. Thrower et al and Zourari et al found that deviations increased with increasing distance from dwell positions [4,5] for breast cases, although in that case this was mostly due to lung heterogeneities.…”

Section: Liver Dosementioning

confidence: 92%

The dosimetric impact of replacing the TG-43 algorithm by model based dose calculation for liver brachytherapy

et al. 2020

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“…As shown by Lesperance et al, using a less water equivalent material for the tumor results in larger differences in dose to the tumor compared to the water‐based scenario. When prescribing dose to the tumor apex this will also change the dose received in all other parts of the eye, demonstrating the importance of accurate material compositions for low‐energy brachytherapy, a detail that is not nearly as critical for high‐energy treatments …”

Section: Discussionmentioning

confidence: 99%

“…When prescribing dose to the tumor apex this will also change the dose received in all other parts of the eye, demonstrating the importance of accurate material compositions for lowenergy brachytherapy, a detail that is not nearly as critical for high-energy treatments. 9,[39][40][41][42] Transitioning from the traditional TG-43 dose reporting scheme (augmented with corrections for the plaque materials) to a dose to medium reporting scheme is expected to result in more accurate knowledge of doses to various structures in the eye. However, understanding the underlying factors that cause the changes in dose compared to water-based planning will be important to appreciate the clinical implications of implementing model-based dose calculations.…”

Section: Discussionmentioning

confidence: 99%

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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“…compared ACE ( D m,m ) and TG-43 dosimetry using Oncentra Brachy v.4.4 [42]. An analysis of clinically relevant dose-volume parameters for PTV, breast, lung, heart, rib, and skin revealed statistically significant differences for all parameters, except for heart.…”

Section: Experience Using Commercial Model-based Dose Calculation Algmentioning

confidence: 99%

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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A retrospective dosimetric comparison of TG43 and a commercially available MBDCA for an APBI brachytherapy patient cohort

Cited by 30 publications

References 22 publications

The dosimetric impact of replacing the TG-43 algorithm by model based dose calculation for liver brachytherapy

The dosimetric impact of replacing the TG-43 algorithm by model based dose calculation for liver brachytherapy

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

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

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