PMID- 28151727
OWN - NLM
STAT- MEDLINE
DCOM- 20171012
LR  - 20181202
IS  - 1361-6560 (Electronic)
IS  - 0031-9155 (Linking)
VI  - 62
IP  - 6
DP  - 2017 Mar 21
TI  - Contour scanning for penumbra improvement in pencil beam scanned proton therapy.
PG  - 2398-2416
LID - 10.1088/1361-6560/aa5dde [doi]
AB  - Proton therapy, especially in the form of pencil beam scanning (PBS), allows for 
      the delivery of highly conformal dose distributions for complex tumor geometries. 
      However, due to scattering of protons inside the patient, lateral dose gradients 
      cannot be arbitrarily steep, which is of importance in cases with organs at risk 
      (OARs) in close proximity to, or overlapping with, planning target volumes 
      (PTVs). In the PBS approach, physical pencil beams are planned using a regular 
      grid orthogonal to the beam direction. In this work, we propose an alternative to 
      this commonly used approach where pencil beams are placed on an irregular grid 
      along concentric paths based on the target contour. Contour driven pencil beam 
      placement is expected to improve dose confirmation by allowing the optimizer to 
      best enhance the penumbra of irregularly shaped targets using edge enhancement. 
      Its effectiveness has been shown to improve dose confirmation to the target 
      volume and reduce doses to OARs in head-and-neck planning studies. Furthermore, 
      the deliverability of such plans, as well as the dosimetric improvements over 
      conventional grid-based plans, have been confirmed in first phantom based 
      verifications.
FAU - Meier, G
AU  - Meier G
AD  - Centre for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland. ETH 
      Zurich, Zurich, Switzerland.
FAU - Leiser, D
AU  - Leiser D
FAU - Besson, R
AU  - Besson R
FAU - Mayor, A
AU  - Mayor A
FAU - Safai, S
AU  - Safai S
FAU - Weber, D C
AU  - Weber DC
FAU - Lomax, A J
AU  - Lomax AJ
LA  - eng
PT  - Journal Article
DEP - 20170202
PL  - England
TA  - Phys Med Biol
JT  - Physics in medicine and biology
JID - 0401220
SB  - IM
MH  - Humans
MH  - Organs at Risk
MH  - Phantoms, Imaging
MH  - Proton Therapy/*methods/standards
MH  - Radiation Dosage
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted/*methods/standards
MH  - Radiotherapy, Intensity-Modulated/*methods/standards
EDAT- 2017/02/06 06:00
MHDA- 2017/10/13 06:00
CRDT- 2017/02/03 06:00
PHST- 2017/02/06 06:00 [pubmed]
PHST- 2017/10/13 06:00 [medline]
PHST- 2017/02/03 06:00 [entrez]
AID - 10.1088/1361-6560/aa5dde [doi]
PST - ppublish
SO  - Phys Med Biol. 2017 Mar 21;62(6):2398-2416. doi: 10.1088/1361-6560/aa5dde. Epub 
      2017 Feb 2.