PMID- 29191470
OWN - NLM
STAT- MEDLINE
DCOM- 20181119
LR  - 20181119
IS  - 1873-4022 (Electronic)
IS  - 1873-4022 (Linking)
VI  - 43
IP  - 3
DP  - 2018 Autumn
TI  - Optimal beam margins in linac-based VMAT stereotactic ablative body radiotherapy: 
      a Pareto front analysis for liver metastases.
PG  - 291-301
LID - S0958-3947(17)30120-6 [pii]
LID - 10.1016/j.meddos.2017.10.006 [doi]
AB  - We explored the Pareto fronts mathematical strategy to determine the optimal 
      block margin and prescription isodose for stereotactic body radiotherapy (SBRT) 
      treatments of liver metastases using the volumetric-modulated arc therapy (VMAT) 
      technique. Three targets (planning target volumes [PTVs] = 20, 55, and 101 cc) 
      were selected. A single fraction dose of 26 Gy was prescribed (prescription dose 
      [PD]). VMAT plans were generated for 3 different beam energies. Pareto fronts 
      based on (1) different multileaf collimator (MLC) block margin around PTV and (2) 
      different prescription isodose lines (IDL) were produced. For each block margin, 
      the greatest IDL fulfilling the criteria (95% of PTV reached 100%) was considered 
      as providing the optimal clinical plan for PTV coverage. Liver D(mean), V7Gy, and 
      V12Gy were used against the PTV coverage to generate the fronts. Gradient indexes 
      (GI and mGI), homogeneity index (HI), and healthy liver irradiation in terms of 
      D(mean), V7Gy, and V12Gy were calculated to compare different plans. In addition, 
      each target was also optimized with a full-inverse planning engine to obtain a 
      direct comparison with anatomy-based treatment planning system (TPS) results. 
      About 900 plans were calculated to generate the fronts. GI and mGI show a 
      U-shaped behavior as a function of beam margin with minimal values obtained with 
      a +1 mm MLC margin. For these plans, the IDL ranges from 74% to 86%. GI and mGI 
      show also a V-shaped behavior with respect to HI index, with minimum values at 
      1 mm for all metrics, independent of tumor dimensions and beam energy. 
      Full-inversed optimized plans reported worse results with respect to Pareto 
      plans. In conclusion, Pareto fronts provide a rigorous strategy to choose 
      clinical optimal plans in SBRT treatments. We show that a 1-mm MLC block margin 
      provides the best results with regard to healthy liver tissue irradiation and 
      steepness of dose fallout.
CI  - Copyright (c) 2017 American Association of Medical Dosimetrists. Published by 
      Elsevier Inc. All rights reserved.
FAU - Cilla, Savino
AU  - Cilla S
AD  - Medical Physics Unit, Fondazione di Ricerca e Cura Giovanni Paolo II-Universita 
      Cattolica del Sacro Cuore, Campobasso, Italy. Electronic address: 
      savino.cilla@fgps.it.
FAU - Ianiro, Anna
AU  - Ianiro A
AD  - Medical Physics Unit, Fondazione di Ricerca e Cura Giovanni Paolo II-Universita 
      Cattolica del Sacro Cuore, Campobasso, Italy.
FAU - Deodato, Francesco
AU  - Deodato F
AD  - Radiation Oncology Unit, Fondazione di Ricerca e Cura Giovanni Paolo 
      II-Universita Cattolica del Sacro Cuore, Campobasso, Italy.
FAU - Macchia, Gabriella
AU  - Macchia G
AD  - Radiation Oncology Unit, Fondazione di Ricerca e Cura Giovanni Paolo 
      II-Universita Cattolica del Sacro Cuore, Campobasso, Italy.
FAU - Digesu, Cinzia
AU  - Digesu C
AD  - Radiation Oncology Unit, Fondazione di Ricerca e Cura Giovanni Paolo 
      II-Universita Cattolica del Sacro Cuore, Campobasso, Italy.
FAU - Valentini, Vincenzo
AU  - Valentini V
AD  - Radiation Oncology Unit, Fondazione di Ricerca e Cura Giovanni Paolo 
      II-Universita Cattolica del Sacro Cuore, Campobasso, Italy; Radiation Oncology 
      Department, Policlinico Universitario A. Gemelli-Universita Cattolica del Sacro 
      Cuore, Roma, Italy.
FAU - Morganti, Alessio G
AU  - Morganti AG
AD  - Radiation Oncology Department, DIMES Universita di Bologna-Ospedale S.Orsola 
      Malpighi, Bologna, Italy.
LA  - eng
PT  - Journal Article
DEP - 20171127
PL  - United States
TA  - Med Dosim
JT  - Medical dosimetry : official journal of the American Association of Medical 
      Dosimetrists
JID - 8908862
SB  - IM
MH  - Humans
MH  - Liver Neoplasms/*radiotherapy/secondary
MH  - *Radiosurgery
MH  - *Radiotherapy Planning, Computer-Assisted
MH  - *Radiotherapy, Intensity-Modulated
OTO - NOTNLM
OT  - Pareto
OT  - Planning optimization
OT  - SBRT
OT  - VMAT
EDAT- 2017/12/02 06:00
MHDA- 2018/11/20 06:00
CRDT- 2017/12/02 06:00
PHST- 2017/06/20 00:00 [received]
PHST- 2017/09/21 00:00 [revised]
PHST- 2017/10/23 00:00 [accepted]
PHST- 2017/12/02 06:00 [pubmed]
PHST- 2018/11/20 06:00 [medline]
PHST- 2017/12/02 06:00 [entrez]
AID - S0958-3947(17)30120-6 [pii]
AID - 10.1016/j.meddos.2017.10.006 [doi]
PST - ppublish
SO  - Med Dosim. 2018 Autumn;43(3):291-301. doi: 10.1016/j.meddos.2017.10.006. Epub 
      2017 Nov 27.