PMID- 30188866
OWN - NLM
STAT- MEDLINE
DCOM- 20190801
LR  - 20190801
IS  - 1361-6560 (Electronic)
IS  - 0031-9155 (Linking)
VI  - 63
IP  - 24
DP  - 2018 Dec 10
TI  - Patient positioning verification for proton therapy using proton radiography.
PG  - 245009
LID - 10.1088/1361-6560/aadf79 [doi]
AB  - We present a proof of principle, experimental validation of the potential of 
      proton 'Range Probes' (RP) for patient positioning verification in proton 
      therapy. In this work, we have evaluated experimentally the accuracy of RP by 
      using tissue-like samples and an in-house developed multilayer ionization chamber 
      (MLIC). In addition we build on our previous, simulation based work to present 
      first experimental measurements of RP through anthropomorphic phantoms to detect 
      either rotational or translational positioning errors. For this, a technique has 
      been proposed to characterize the residual integral depth dose curve (RIDDC) 
      after range mixing. This parametrization has been used to evaluate the similarity 
      between Monte Carlo calculated error scenarios of the database and the measured 
      RIDDC, while considering the intrinsic uncertainties of both modalities in order 
      to deduce the positioning error. Finally, the additional dose applied to the 
      patient when using clinical RP with known fluence has been estimated by measuring 
      the local dose of a single RP. In tissue phantoms, the prediction accuracy of the 
      water equivalent path length was 0.70%, with the highest deviations being found 
      in low density samples (up to 5.67%). In addition, the results of the patient 
      positioning verification measurements demonstrated that using carefully selected 
      RPs, 1D translational or rotational errors could be detected with an accuracy of 
      1 mm and 2 degrees , respectively, and that these would be associated with a low 
      additional dose burden to the patient. In summary, these promising results 
      suggest that the RP method could be a simple, fast and low-dose tool for 
      verifying patient set-up during proton therapy treatment.
FAU - Hammi, A
AU  - Hammi A
AD  - Center for Proton Radiation Therapy, Paul Scherrer Institute, 5232 Villigen-PSI, 
      Switzerland. Swiss Federal Institute of Technology in Zurich, Raemistrasse 101, 
      8092 Zurich, Switzerland.
FAU - Koenig, S
AU  - Koenig S
FAU - Weber, D C
AU  - Weber DC
FAU - Poppe, B
AU  - Poppe B
FAU - Lomax, A J
AU  - Lomax AJ
LA  - eng
PT  - Journal Article
DEP - 20181210
PL  - England
TA  - Phys Med Biol
JT  - Physics in medicine and biology
JID - 0401220
MH  - Humans
MH  - Monte Carlo Method
MH  - Patient Positioning/*methods
MH  - Phantoms, Imaging
MH  - Proton Therapy/*methods
MH  - Radiography/methods
MH  - Radiotherapy Planning, Computer-Assisted/methods
EDAT- 2018/09/07 06:00
MHDA- 2019/08/02 06:00
CRDT- 2018/09/07 06:00
PHST- 2018/09/07 06:00 [pubmed]
PHST- 2019/08/02 06:00 [medline]
PHST- 2018/09/07 06:00 [entrez]
AID - 10.1088/1361-6560/aadf79 [doi]
PST - epublish
SO  - Phys Med Biol. 2018 Dec 10;63(24):245009. doi: 10.1088/1361-6560/aadf79.