Comparison of Dose Distributions With TG-43 and Collapsed Cone Convolution Algorithms Applied to Accelerated Partial Breast Irradiation Patient Plans

Thrower, Sara L.; Shaitelman, Simona F.; Bloom, Elizabeth Stroh; Salehpour, Mohammad; Gifford, Kent A

doi:10.1016/j.ijrobp.2016.03.033

Cited by 10 publications

(6 citation statements)

References 19 publications

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“…Our calculations found TG-186-calculated DVH-parameters to be in general lower than TG-43U1calculated parameters. This is in good agreement with the results of other groups who reported an overestimation of TG-43U1 in comparison to TG-186 for soft tissue in other tumour entities [4,6,8,10] [8]. For cervix cancer patients, Jacob et al compared TG-43 to D m,m and reported changes in target coverage parameter D 90 of 2.6%, with similar values for D 95 and D 100 .…”

Section: Discussionsupporting

confidence: 90%

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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: Discussionsupporting

confidence: 90%

“…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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“…using AcurosBV (calculating D w,m ) for ten patients treated with flexible plastic catheters [41], and by Thrower et al . using ACE (calculating D m,m ) for 50 patients treated with a SAVI or Contura device [43]. These studies found dose differences for the CTV and OARs relative to TG-43 to be consistent with those of earlier investigations, insofar as direct comparisons were possible.…”

Section: Experience Using Commercial Model-based Dose Calculation Algsupporting

confidence: 66%

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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“…AAPM has published Task Group 186, which guides beginners regarding MBDCAs for BT dose calculations and ensures uniformity in practice. Previous papers have already demonstrated the efficacy of MBDCAs for phantoms and for several treatment sites, such as breast tissue [ 15 – 19 ]. However, to date, there has been minimal evaluation of the impact of MBDCAs on the treatment of cervical cancer, particularly for the Advanced Collapsed cone Engine (ACE) method [ 16 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Impact of a commercially available model-based dose calculation algorithm on treatment planning of high-dose-rate brachytherapy in patients with cervical cancer

Abe

Sato

Hashimoto

et al. 2018

Journal of Radiation Research

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We evaluated the impact of model-based dose calculation algorithms (MBDCAs) on high-dose-rate brachytherapy (HDR-BT) treatment planning for patients with cervical cancer. Seven patients with cervical cancer treated using HDR-BT were studied. Tandem and ovoid applicators were used in four patients, a vaginal cylinder in one, and interstitial needles in the remaining two patients. MBDCAs were applied to the Advanced Collapsed cone Engine (ACE; Elekta, Stockholm, Sweden). All plans, which were originally calculated using TG-43, were re-calculated using both ACE and Monte Carlo (MC) simulations. Air was used as the rectal material. The mean difference in the rectum D2cm3 between ACErec-air and MCrec-air was 8.60 ± 4.64%, whereas that in the bladder D2cm3 was −2.80 ± 1.21%. Conversely, in the small group analysis (n = 4) using water instead of air as the rectal material, the mean difference in the rectum D2cm3 between TG-43 and ACErec-air was 11.87 ± 2.65%, whereas that between TG-43 and ACErec-water was 0.81 ± 2.04%, indicating that the use of water as the rectal material reduced the difference in D2cm3 between TG-43 and ACE. Our results suggested that the differences in the dose–volume histogram (DVH) parameters of TG-43 and ACE were large for the rectum when considerable air (gas) volume was present in it, and that this difference was reduced when the air (gas) volume was reduced. Also, ACE exhibited better dose calculation accuracy than that of TG-43 in this situation. Thus, ACE may be able to calculate the dose more accurately than TG-43 for HDR-BT in treating cervical cancers, particularly for patients with considerable air (gas) volume in the rectum.

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Comparison of Dose Distributions With TG-43 and Collapsed Cone Convolution Algorithms Applied to Accelerated Partial Breast Irradiation Patient Plans

Cited by 10 publications

References 19 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

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

Impact of a commercially available model-based dose calculation algorithm on treatment planning of high-dose-rate brachytherapy in patients with cervical cancer

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