PMID- 23714579
OWN - NLM
STAT- MEDLINE
DCOM- 20150512
LR  - 20211021
IS  - 1748-717X (Electronic)
IS  - 1748-717X (Linking)
VI  - 8
DP  - 2013 May 28
TI  - The influence of MRI scan position on patients with oropharyngeal cancer 
      undergoing radical radiotherapy.
PG  - 129
LID - 10.1186/1748-717X-8-129 [doi]
AB  - BACKGROUND: The purpose of this study was to demonstrate how magnetic resonance 
      imaging (MRI) patient position protocols influence registration quality in 
      patients with oropharyngeal cancer undergoing radical radiotherapy and the 
      consequences for gross tumour volume (GTV) definition and radiotherapy planning. 
      METHODS AND MATERIALS: Twenty-two oropharyngeal patients underwent a computed 
      tomography (CT), a diagnostic MRI (MRI(D)) and an MRI in the radiotherapy 
      position within an immobilization mask (MRI(RT)). Clinicians delineated the GTV 
      on the CT viewing the MRI(D) separately (GTV(C)); on the CT registered to MRI(D) 
      (GTV(D)) and on the CT registered to MRI(RT) (GTV(RT)). Planning target volumes 
      (PTVs) were denoted similarly. Registration quality was assessed by measuring 
      disparity between structures in the three set-ups. Volumetric modulated arc 
      therapy (VMAT) radiotherapy planning was performed for PTV(C), PTV(D) and 
      PTV(RT). To determine the dose received by the reference PTV(RT), we optimized 
      for PTV(C) and PTV(D) while calculating the dose to PTV(RT). Statistical 
      significance was determined using the two-tailed Mann-Whitney or two-tailed 
      paired student t-tests. RESULTS: A significant improvement in registration 
      accuracy was found between CT and MRI(RT) versus the MRI(D) measuring distances 
      from the centre of structures (geometric mean error of 2.2 mm versus 6.6 mm). The 
      mean GTV(C) (44.1 cm3) was significantly larger than GTV(D) (33.7 cm3, p 
      value = 0.027) or GTV(RT) (30.5 cm3, p value = 0.014). When optimizing the VMAT 
      plans for PTV(C) and investigating the mean dose to PTV(RT) neither the dose to 
      99% (58.8%) nor 95% of the PTV (84.7%) were found to meet the required clinical 
      dose constraints of 90% and 95% respectively. Similarly, when optimizing for 
      PTV(D) the mean dose to PTV(RT) did not meet clinical dose constraints for 99% 
      (14.9%) nor 95% of the PTV (66.2%). Only by optimizing for PTV(RT) were all 
      clinical dose constraints achieved. CONCLUSIONS: When oropharyngeal patients MRI 
      scans are performed in the radiotherapy position there are significant 
      improvements in CT-MR image registration, target definition and PTV dose 
      coverage.
FAU - Hanvey, Scott
AU  - Hanvey S
FAU - McJury, Mark
AU  - McJury M
FAU - Tho, Lye Mun
AU  - Tho LM
FAU - Glegg, Martin
AU  - Glegg M
FAU - Thomson, Maureen
AU  - Thomson M
FAU - Grose, Derek
AU  - Grose D
FAU - James, Allan
AU  - James A
FAU - Rizwanullah, Mohammed
AU  - Rizwanullah M
FAU - Paterson, Claire
AU  - Paterson C
FAU - Foster, John
AU  - Foster J
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20130528
PL  - England
TA  - Radiat Oncol
JT  - Radiation oncology (London, England)
JID - 101265111
SB  - IM
MH  - Adult
MH  - Aged
MH  - Female
MH  - Humans
MH  - Magnetic Resonance Imaging/*methods
MH  - Male
MH  - Middle Aged
MH  - Multimodal Imaging
MH  - Oropharyngeal Neoplasms/*radiotherapy
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Radiotherapy, Intensity-Modulated
MH  - Tomography, X-Ray Computed
PMC - PMC3681609
EDAT- 2013/05/30 06:00
MHDA- 2015/05/13 06:00
PMCR- 2013/05/28
CRDT- 2013/05/30 06:00
PHST- 2012/12/19 00:00 [received]
PHST- 2013/05/24 00:00 [accepted]
PHST- 2013/05/30 06:00 [entrez]
PHST- 2013/05/30 06:00 [pubmed]
PHST- 2015/05/13 06:00 [medline]
PHST- 2013/05/28 00:00 [pmc-release]
AID - 1748-717X-8-129 [pii]
AID - 10.1186/1748-717X-8-129 [doi]
PST - epublish
SO  - Radiat Oncol. 2013 May 28;8:129. doi: 10.1186/1748-717X-8-129.