PMID- 30102240
OWN - NLM
STAT- MEDLINE
DCOM- 20190820
LR  - 20190820
IS  - 1361-6560 (Electronic)
IS  - 0031-9155 (Linking)
VI  - 63
IP  - 18
DP  - 2018 Sep 13
TI  - Exploration and application of phenomenological RBE models for proton therapy.
PG  - 185013
LID - 10.1088/1361-6560/aad9db [doi]
AB  - The relative biological effectiveness (RBE) of protons varies with multiple 
      physical and biological factors. Phenomenological RBE models have been developed 
      to include such factors in the estimation of a variable RBE, in contrast to the 
      clinically applied constant RBE of 1.1. In this study, eleven published 
      phenomenological RBE models and two plan-based models were explored and applied 
      to simulated patient cases. All models were analysed with respect to the 
      distribution and range of linear energy transfer (LET) and reference radiation 
      fractionation sensitivity ((alpha/beta) (x) ) of their respective experimental 
      databases. Proton therapy plans for a spread-out Bragg peak in water and three 
      patient cases (prostate adenocarcinoma, pituitary adenoma and thoracic sarcoma) 
      were optimised using an RBE of 1.1 in the Eclipse() treatment planning system 
      prior to recalculation and modelling in the FLUKA Monte Carlo code. Model 
      estimated dose-volume parameters for the planning target volumes (PTVs) and 
      organs at risk (OAR) were compared. The experimental in vitro databases for the 
      various models differed greatly in the range of (alpha/beta) (x) values and 
      dose-averaged LET (LET(d)). There were significant variations between the model 
      estimations, which arose from fundamental differences in the database definitions 
      and model assumptions. The greatest variations appeared in organs with low (alpha/beta) 
      (x) and high LET(d), e.g. biological doses given to late responding OARs located 
      distal to the target in the treatment field. In general, the variation in maximum 
      dose (D(2%)) was larger than the variation in mean dose and other dose metrics, 
      with D(2%) of the left optic nerve ((alpha/beta) (x)   =  2.1 Gy) in the pituitary 
      adenoma case showing the greatest discrepancies between models: 28-52 Gy(RBE), 
      while D(2%) for RBE(1.1) was 30 Gy(RBE). For all patient cases, the estimated 
      mean RBE to the PTV was in the range 1.09-1.29 ((alpha/beta) (x)   =  1.5/3.1/10.6 Gy). 
      There were considerable variations between the estimations of RBE and 
      RBE-weighted doses from the different models. These variations were a consequence 
      of fundamental differences in experimental databases, model assumptions and 
      regression techniques. The results from the implementation of RBE models in dose 
      planning studies should be evaluated in light of these deviations.
FAU - Rorvik, Eivind
AU  - Rorvik E
AD  - Department of Physics and Technology, University of Bergen, Bergen, Norway. 
      Author to whom any correspondence should be addressed.
FAU - Fjaera, Lars Fredrik
AU  - Fjaera LF
FAU - Dahle, Tordis J
AU  - Dahle TJ
FAU - Dale, Jon Espen
AU  - Dale JE
FAU - Engeseth, Grete May
AU  - Engeseth GM
FAU - Stokkevag, Camilla H
AU  - Stokkevag CH
FAU - Thornqvist, Sara
AU  - Thornqvist S
FAU - Ytre-Hauge, Kristian S
AU  - Ytre-Hauge KS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20180913
PL  - England
TA  - Phys Med Biol
JT  - Physics in medicine and biology
JID - 0401220
MH  - Adenocarcinoma/radiotherapy
MH  - Dose Fractionation, Radiation
MH  - Humans
MH  - Linear Energy Transfer
MH  - Male
MH  - Monte Carlo Method
MH  - Neoplasms/*radiotherapy
MH  - Organs at Risk/*radiation effects
MH  - Pituitary Neoplasms/radiotherapy
MH  - Prostatic Neoplasms/radiotherapy
MH  - Proton Therapy/*methods
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - *Relative Biological Effectiveness
MH  - Sarcoma/radiotherapy
MH  - Thoracic Neoplasms/radiotherapy
EDAT- 2018/08/14 06:00
MHDA- 2019/08/21 06:00
CRDT- 2018/08/14 06:00
PHST- 2018/08/14 06:00 [pubmed]
PHST- 2019/08/21 06:00 [medline]
PHST- 2018/08/14 06:00 [entrez]
AID - 10.1088/1361-6560/aad9db [doi]
PST - epublish
SO  - Phys Med Biol. 2018 Sep 13;63(18):185013. doi: 10.1088/1361-6560/aad9db.