PMID- 28423966
OWN - NLM
STAT- MEDLINE
DCOM- 20180213
LR  - 20180213
IS  - 1651-226X (Electronic)
IS  - 0284-186X (Linking)
VI  - 56
IP  - 6
DP  - 2017 Jun
TI  - Linear energy transfer distributions in the brainstem depending on tumour 
      location in intensity-modulated proton therapy of paediatric cancer.
PG  - 763-768
LID - 10.1080/0284186X.2017.1314007 [doi]
AB  - BACKGROUND: For tumours near organs at risk, there is concern about unintended 
      increase in biological dose from elevated linear energy transfer (LET) at the 
      distal end of treatment fields. The objective of this study was therefore to 
      investigate how different paediatric posterior fossa tumour locations impact LET 
      and biological dose to the brainstem during intensity-modulated proton therapy 
      (IMPT). MATERIAL AND METHODS: Multiple IMPT plans were generated for four 
      different simulated tumour locations relative to the brainstem for a 
      five-year-old male patient. A prescribed dose of 59.4 Gy(RBE) was applied to the 
      planning target volumes (PTVs). Plans with two lateral and one posterior 
      non-coplanar fields were created, along with plans with modified field 
      arrangements. The dose-averaged LET (LET(d)) and the physical dose x RBE(LET) 
      (D x RBE(LET)), where RBE(LET)=1+c x LET(d), were calculated using the FLUKA 
      Monte Carlo code. A scaling parameter c was applied to make the RBE(LET) 
      represent variations in the biological effect due to LET. RESULTS: High LET(d) 
      values surrounded parts of the PTV and encompassed portions of the brainstem. 
      Mean LET(d) values in the brainstem were 3.2-6.6 keV/mum. The highest absolute 
      brainstem LET(d) values were seen with the tumour located most distant from the 
      brainstem, whereas lower and more homogeneous LET(d) values were seen when the 
      tumour invaded the brainstem. In contrast, the highest mean D x RBE(LET) values 
      were found in the latter case (54.0 Gy(RBE)), while the case with largest 
      distance between tumour and brainstem had a mean D x RBE(LET) of 1.8 Gy(RBE). 
      CONCLUSIONS: Using IMPT to treat posterior fossa tumours may result in high 
      LET(d) values within the brainstem, particularly if the tumour volume is 
      separated from the brainstem. However, the D x RBE(LET) was greater for tumours 
      that approached or invaded the brainstem. Changing field angles showed a 
      reduction of LET(d) and D x RBE(LET) in the brainstem.
FAU - Fjaera, Lars Fredrik
AU  - Fjaera LF
AD  - a Department of Physics and Technology , University of Bergen , Bergen , Norway.
AD  - b Department of Oncology and Medical Physics , Haukeland University Hospital , 
      Bergen , Norway.
FAU - Li, Zuofeng
AU  - Li Z
AD  - c Department of Radiation Oncology , University of Florida , Jacksonville , FL , 
      USA.
FAU - Ytre-Hauge, Kristian S
AU  - Ytre-Hauge KS
AD  - a Department of Physics and Technology , University of Bergen , Bergen , Norway.
FAU - Muren, Ludvig P
AU  - Muren LP
AD  - d Department of Medical Physics , Aarhus University/Aarhus University Hospital , 
      Aarhus , Denmark.
FAU - Indelicato, Daniel J
AU  - Indelicato DJ
AD  - c Department of Radiation Oncology , University of Florida , Jacksonville , FL , 
      USA.
FAU - Lassen-Ramshad, Yasmin
AU  - Lassen-Ramshad Y
AD  - e Department of Oncology , Aarhus University Hospital , Aarhus , Denmark.
FAU - Engeseth, Grete May
AU  - Engeseth GM
AD  - b Department of Oncology and Medical Physics , Haukeland University Hospital , 
      Bergen , Norway.
FAU - Brydoy, Marianne
AU  - Brydoy M
AD  - b Department of Oncology and Medical Physics , Haukeland University Hospital , 
      Bergen , Norway.
FAU - Mairani, Andrea
AU  - Mairani A
AD  - f Medical Physics Unit , CNAO Foundation , Pavia , Italy.
AD  - g Heidelberg Ion Beam Therapy Center (HIT) , Heidelberg , Germany.
FAU - Flampouri, Stella
AU  - Flampouri S
AD  - c Department of Radiation Oncology , University of Florida , Jacksonville , FL , 
      USA.
FAU - Dahl, Olav
AU  - Dahl O
AD  - b Department of Oncology and Medical Physics , Haukeland University Hospital , 
      Bergen , Norway.
FAU - Stokkevag, Camilla H
AU  - Stokkevag CH
AD  - b Department of Oncology and Medical Physics , Haukeland University Hospital , 
      Bergen , Norway.
LA  - eng
PT  - Case Reports
PT  - Journal Article
DEP - 20170419
PL  - Sweden
TA  - Acta Oncol
JT  - Acta oncologica (Stockholm, Sweden)
JID - 8709065
SB  - IM
MH  - Brain Stem Neoplasms/pathology/*radiotherapy
MH  - Child
MH  - Humans
MH  - *Linear Energy Transfer
MH  - Male
MH  - Organs at Risk/*radiation effects
MH  - *Proton Therapy
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Radiotherapy, Intensity-Modulated/methods
MH  - Relative Biological Effectiveness
EDAT- 2017/04/21 06:00
MHDA- 2018/02/14 06:00
CRDT- 2017/04/21 06:00
PHST- 2017/04/21 06:00 [pubmed]
PHST- 2018/02/14 06:00 [medline]
PHST- 2017/04/21 06:00 [entrez]
AID - 10.1080/0284186X.2017.1314007 [doi]
PST - ppublish
SO  - Acta Oncol. 2017 Jun;56(6):763-768. doi: 10.1080/0284186X.2017.1314007. Epub 2017 
      Apr 19.