PMID- 23786885
OWN - NLM
STAT- MEDLINE
DCOM- 20140930
LR  - 20161125
IS  - 1724-191X (Electronic)
IS  - 1120-1797 (Linking)
VI  - 30
IP  - 2
DP  - 2014 Mar
TI  - Gantry angle-dependent correction of dose detection error due to panel position 
      displacement in IMRT dose verification using EPIDs.
PG  - 209-14
LID - S1120-1797(13)00108-7 [pii]
LID - 10.1016/j.ejmp.2013.05.042 [doi]
AB  - PURPOSE: The purpose of this study was to measure the mechanical position 
      displacement of three types of electronic portal image device (EPID) panels at 
      different gantry angles and evaluate the impact of positional displacement on 
      intensity modulated radiation therapy (IMRT) dose verification using an EPID. 
      METHODS: Three types of linear accelerators and EPIDs (aS500, aS1000 and iViewGT) 
      were used. The portal images were taken every 10 degrees  within 360 degrees  range. The position 
      coordinate difference between the panel center and the portal film center at 
      different gantry angles was measured, then the mechanical position displacement 
      of EPIDs dependent on the gantry angles was analyzed. For the three linear 
      accelerators and EPIDs, five IMRT plans were measured using EPIDs at 0 degrees  gantry 
      angel and at the actual treatment angles. The Gamma technique was used to 
      evaluate the resulted dose difference before and after the corrections of the 
      position displacement by a in-house software. RESULTS: For aS500, aS1000 and 
      iViewGT, the maximum mechanical position displacement was 2.9 +/- 0.1 mm, 
      0.2 +/- 0.1 mm and 0.1 +/- 0.3 mm in the lateral direction 
      and -4.2 +/- 0.2 mm, -4.2 +/- 0.1 mm and -2.2 +/- 0.1 mm in the longitudinal direction, 
      respectively. The position displacement in the longitudinal direction of the 
      three EPIDs can be fitted well with a function. For aS500, aS1000 and iViewGT, 
      the 3%/3 mm gamma pass rates were increased by 6.7%, 2.9% and 0.1% after 
      displacement corrections; and while the 2%/2 mm gamma pass rates were increased 
      by 11.2%, 8.1% and 1.6%. After the displacement correction, there was a slight 
      gamma pass rate difference between the fixed zero degree gantry and the actual 
      treatment angles. CONCLUSION: When the EPIDs were used for IMRT dose 
      verification, there was occasionally large EPID mechanical position displacement, 
      which should be corrected.
CI  - Copyright (c) 2013 Associazione Italiana di Fisica Medica. Published by Elsevier 
      Ltd. All rights reserved.
FAU - Jin, Guang-hua
AU  - Jin GH
AD  - School of Physics and Engineering of SUN Yat-sen University, Guangzhou 510060, 
      China; Department of Radiation Oncology, SUN Yat-sen University Cancer Center, 
      State Key Laboratory of Oncology in Southern China, Guangzhou 510060, China.
FAU - Zhu, Jin-han
AU  - Zhu JH
AD  - School of Physics and Engineering of SUN Yat-sen University, Guangzhou 510060, 
      China; Department of Radiation Oncology, SUN Yat-sen University Cancer Center, 
      State Key Laboratory of Oncology in Southern China, Guangzhou 510060, China.
FAU - Chen, Li-xin
AU  - Chen LX
AD  - Department of Radiation Oncology, SUN Yat-sen University Cancer Center, State Key 
      Laboratory of Oncology in Southern China, Guangzhou 510060, China.
FAU - Deng, Xiao-wu
AU  - Deng XW
AD  - Department of Radiation Oncology, SUN Yat-sen University Cancer Center, State Key 
      Laboratory of Oncology in Southern China, Guangzhou 510060, China.
FAU - Huang, Bo-tian
AU  - Huang BT
AD  - Department of Radiation Oncology, SUN Yat-sen University Cancer Center, State Key 
      Laboratory of Oncology in Southern China, Guangzhou 510060, China.
FAU - Yuan, Ke
AU  - Yuan K
AD  - Department of Radiation Oncology, SUN Yat-sen University Cancer Center, State Key 
      Laboratory of Oncology in Southern China, Guangzhou 510060, China.
FAU - Liu, Xiao-wei
AU  - Liu XW
AD  - School of Physics and Engineering of SUN Yat-sen University, Guangzhou 510060, 
      China. Electronic address: stslxw@mail.sysu.edu.cn.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20130617
PL  - Italy
TA  - Phys Med
JT  - Physica medica : PM : an international journal devoted to the applications of 
      physics to medicine and biology : official journal of the Italian Association of 
      Biomedical Physics (AIFB)
JID - 9302888
SB  - IM
MH  - *Artifacts
MH  - *Electrical Equipment and Supplies
MH  - *Mechanical Phenomena
MH  - Particle Accelerators
MH  - *Radiation Dosage
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted/*instrumentation
MH  - Radiotherapy, Intensity-Modulated/*instrumentation
MH  - Reproducibility of Results
MH  - Rotation
OTO - NOTNLM
OT  - Dose
OT  - EPID
OT  - IMRT
OT  - Position displacement
EDAT- 2013/06/22 06:00
MHDA- 2014/10/01 06:00
CRDT- 2013/06/22 06:00
PHST- 2013/01/31 00:00 [received]
PHST- 2013/05/24 00:00 [revised]
PHST- 2013/05/27 00:00 [accepted]
PHST- 2013/06/22 06:00 [entrez]
PHST- 2013/06/22 06:00 [pubmed]
PHST- 2014/10/01 06:00 [medline]
AID - S1120-1797(13)00108-7 [pii]
AID - 10.1016/j.ejmp.2013.05.042 [doi]
PST - ppublish
SO  - Phys Med. 2014 Mar;30(2):209-14. doi: 10.1016/j.ejmp.2013.05.042. Epub 2013 Jun 
      17.