PMID- 28462867
OWN - NLM
STAT- MEDLINE
DCOM- 20180118
LR  - 20191210
IS  - 1724-191X (Electronic)
IS  - 1120-1797 (Linking)
VI  - 41
DP  - 2017 Sep
TI  - Monte Carlo dose calculation in presence of low-density media: Application to 
      lung SBRT treated during DIBH.
PG  - 46-52
LID - S1120-1797(17)30095-9 [pii]
LID - 10.1016/j.ejmp.2017.04.009 [doi]
AB  - PURPOSE: Commercial algorithms used in Radiotherapy include approximations that 
      are generally acceptable. However their limits can be seen when confronted with 
      small fields and low-density media. These conditions exist during the treatment 
      of lung cancers with Stereotactic Body Radiation Therapy (SBRT) achieved with the 
      "Deep Inspiration Breath Hold" (DIBH) technique. A Monte Carlo (MC) model of a 
      linear accelerator was used to assess the performance of two algorithms (Varian 
      Acuros and AAA) in these conditions. This model is validated using phantoms with 
      different densities. Lastly, results for SBRT cases are compared to both Acuros 
      and AAA. METHODS: A Varian TrueBeam linac was modeled using GATE/Geant4 and 
      validated by comparing dose distributions for simple fields to measurements in 
      water and in heterogeneous phantoms composed of PMMA and two types of cork 
      (corresponding to lung densities during free-breathing and DIBH). Experimental 
      measurements are also compared to AAA and Acuros. Finally, results of Acuros/AAA 
      are compared to MC for a clinical case (SBRT during DIBH). RESULTS: Based on 1D 
      gamma index comparisons with measurements in water, the TrueBeam model was 
      validated (>97% of points passed this test). In heterogeneous phantoms, and in 
      particular for small field sizes, very low density (0.12g.cm(-3)) and at the edge 
      of the field, MC model was still in good agreement with measurements whilst AAA 
      and Acuros showed discrepancies. With the patient CT, similar differences between 
      MC and AAA/Acuros were observed for static fields but disappeared using an SBRT 
      arc field. CONCLUSIONS: Our MC model is validated and limits of commercial 
      algorithms are shown in very low densities.
CI  - Copyright (c) 2017 Associazione Italiana di Fisica Medica. Published by Elsevier 
      Ltd. All rights reserved.
FAU - Beilla, S
AU  - Beilla S
AD  - CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France.
FAU - Younes, T
AU  - Younes T
AD  - CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France; 
      Department of Medical Physics, IUCT-Oncopole, 1 avenue Irene Jolliot Curie, 
      Toulouse 31059, France.
FAU - Vieillevigne, L
AU  - Vieillevigne L
AD  - CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France; 
      Department of Medical Physics, IUCT-Oncopole, 1 avenue Irene Jolliot Curie, 
      Toulouse 31059, France.
FAU - Bardies, M
AU  - Bardies M
AD  - CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France.
FAU - Franceries, X
AU  - Franceries X
AD  - CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France.
FAU - Simon, L
AU  - Simon L
AD  - CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France; 
      Department of Medical Physics, IUCT-Oncopole, 1 avenue Irene Jolliot Curie, 
      Toulouse 31059, France. Electronic address: luc.simon@inserm.fr.
LA  - eng
PT  - Journal Article
PT  - Validation Study
DEP - 20170424
PL  - Italy
TA  - Phys Med
JT  - Physica medica : PM : an international journal devoted to the applications of 
      physics to medicine and biology : official journal of the Italian Association of 
      Biomedical Physics (AIFB)
JID - 9302888
SB  - IM
MH  - Algorithms
MH  - Breath Holding
MH  - Humans
MH  - Lung Neoplasms/*radiotherapy
MH  - Models, Theoretical
MH  - Monte Carlo Method
MH  - Phantoms, Imaging
MH  - *Radiosurgery
MH  - Radiotherapy Dosage
MH  - *Radiotherapy Planning, Computer-Assisted
OTO - NOTNLM
OT  - DIBH
OT  - Geant4
OT  - Monte-Carlo
OT  - SBRT
EDAT- 2017/05/04 06:00
MHDA- 2018/01/19 06:00
CRDT- 2017/05/03 06:00
PHST- 2016/12/22 00:00 [received]
PHST- 2017/02/22 00:00 [revised]
PHST- 2017/04/09 00:00 [accepted]
PHST- 2017/05/04 06:00 [pubmed]
PHST- 2018/01/19 06:00 [medline]
PHST- 2017/05/03 06:00 [entrez]
AID - S1120-1797(17)30095-9 [pii]
AID - 10.1016/j.ejmp.2017.04.009 [doi]
PST - ppublish
SO  - Phys Med. 2017 Sep;41:46-52. doi: 10.1016/j.ejmp.2017.04.009. Epub 2017 Apr 24.