The dosimetric impact of replacing the TG-43 algorithm by model based dose calculation for liver brachytherapy
Open Access
- 9 March 2020
- journal article
- research article
- Published by Springer Science and Business Media LLC in Radiation Oncology
- Vol. 15 (1), 1-11
- https://doi.org/10.1186/s13014-020-01492-9
Abstract
Purpose To compare treatment plans for interstitial high dose rate (HDR) liver brachytherapy with Ir-192 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.This publication has 44 references indexed in Scilit:
- Report of the Task Group 186 on model‐based dose calculation methods in brachytherapy beyond the TG‐43 formalism: Current status and recommendations for clinical implementationMedical Physics, 2012
- Nuclear Data Sheets for A = 192Nuclear Data Sheets, 2012
- Influence of trace elements in human tissue in low-energy photon brachytherapy dosimetryPhysics in Medicine & Biology, 2012
- Computed Tomography–Guided Brachytherapy for Liver CancerSeminars in Radiation Oncology, 2011
- In vivo assessment of catheter positioning accuracy and prolonged irradiation time on liver tolerance dose after single-fraction 192Ir high-dose-rate brachytherapyRadiation Oncology, 2011
- Validation of a new grid-based Boltzmann equation solver for dose calculation in radiotherapy with photon beamsPhysics in Medicine & Biology, 2010
- Evaluation of high‐energy brachytherapy source electronic disequilibrium and dose from emitted electronsMedical Physics, 2009
- A Monte Carlo study on the effect of seed design on the interseed attenuation in permanent prostate implantsMedical Physics, 2008
- Fifty years of Monte Carlo simulations for medical physicsPhysics in Medicine & Biology, 2006
- Differences in effective dose and energy imparted estimation from PA–AP, RLAT–LLAT projections in pediatric full spine x-ray examination using the Monte Carlo techniquePhysics in Medicine & Biology, 2005