TY - JOUR
TI - Dosimetric and radiobiological comparison of TG-43 and Monte Carlo calculations in 192Ir breast brachytherapy applications
AU - Peppa, V.
AU - Pappas, E.P.
AU - Karaiskos, P.
AU - Major, T.
AU - Polgár, C.
AU - Papagiannis, P.
JO - PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
PY - 2016
VL - 32
TODO - 10
SP - 1245-1251
PB - Associazione Italiana di Fisica Medica
SN - null
TODO - 10.1016/j.ejmp.2016.09.020
TODO - iridium 192;  iridium, algorithm;  Article;  brachytherapy;  breast;  breast cancer;  controlled study;  dose calculation;  dose volume histogram;  dosimetry;  heart;  histogram;  human;  intermethod comparison;  lung;  major clinical study;  Monte Carlo method;  organs at risk;  radiation dose distribution;  radiobiology;  retrospective study;  rib;  skin;  TG 43 calculation;  treatment planning;  biophysics;  brachytherapy;  Breast Neoplasms;  comparative study;  computer simulation;  female;  imaging phantom;  Monte Carlo method;  procedures;  radiotherapy dosage;  radiotherapy planning system;  statistics and numerical data, Algorithms;  Biophysical Phenomena;  Brachytherapy;  Breast Neoplasms;  Computer Simulation;  Female;  Humans;  Iridium Radioisotopes;  Monte Carlo Method;  Phantoms, Imaging;  Radiotherapy Dosage;  Radiotherapy Planning, Computer-Assisted;  Retrospective Studies
TODO - Purpose To investigate the clinical significance of introducing model based dose calculation algorithms (MBDCAs) as an alternative to TG-43 in 192Ir interstitial breast brachytherapy. Materials and methods A 57 patient cohort was used in a retrospective comparison between TG-43 based dosimetry data exported from a treatment planning system and Monte Carlo (MC) dosimetry performed using MCNP v. 6.1 with plan and anatomy information in DICOM-RT format. Comparison was performed for the target, ipsilateral lung, heart, skin, breast and ribs, using dose distributions, dose-volume histograms (DVH) and plan quality indices clinically used for plan evaluation, as well as radiobiological parameters. Results TG-43 overestimation of target DVH parameters is statistically significant but small (less than 2% for the target coverage indices and 4% for homogeneity indices, on average). Significant dose differences (>5%) were observed close to the skin and at relatively large distances from the implant leading to a TG-43 dose overestimation for the organs at risk. These differences correspond to low dose regions (<50% of the prescribed dose), being less than 2% of the prescribed dose. Detected dosimetric differences did not induce clinically significant differences in calculated tumor control probabilities (mean absolute difference <0.2%) and normal tissue complication probabilities. Conclusion While TG-43 shows a statistically significant overestimation of most indices used for plan evaluation, differences are small and therefore not clinically significant. Improved MBDCA dosimetry could be important for re-irradiation, technique inter-comparison and/or the assessment of secondary cancer induction risk, where accurate dosimetry in the whole patient anatomy is of the essence. © 2016 Associazione Italiana di Fisica Medica
ER -