PMID- 25536601
OWN - NLM
STAT- MEDLINE
DCOM- 20180622
LR  - 20181202
IS  - 1107-0625 (Print)
IS  - 1107-0625 (Linking)
VI  - 19
IP  - 4
DP  - 2014 Oct-Dec
TI  - Dosimetric evaluation of nasopharyngeal carcinomas irradiated with different IMRT 
      techniques.
PG  - 953-7
AB  - PURPOSE: To evaluate the performance of volumetric arc therapy (VMAT), dynamic 
      intensity modulated radiotherapy (IMRT) and step-and-shoot IMRT techniques in 
      nasopharyngeal cancer (NPC) patients. METHODS: IMRT plans of 48 NPC patients 
      treated between May 2010 and December 2012, were evaluated. Twenty two patients 
      were planned with VMAT, 18 with dynamic IMRT and 8 with step-and-shoot IMRT. 
      Conformity index (CI) and homogeneity index (HI), the dosimetry of the planning 
      target volumes (PTVs) and organs at risk (OARs) and the monitor units (MU) were 
      evaluated for each IMRT modality. RESULTS: The conformity indices of VMAT and 
      dynamic IMRT were better than step-and-shoot IMRT plans (p<0.05). Step-and-shoot 
      IMRT plans provided better homogeneity than VMAT (p=0.01). MUs for dynamic IMRT 
      were much higher compared to VMAT (p<0.01) and step and- shoot IMRT (p<0.01). 
      There was no significant difference between the 3 techniques in terms of PTV70 
      mean doses. When compared with step-and-shoot IMRT, VMAT and dynamic IMRT had a 
      better sparing effect on optic nerves, eyes and optic chiasm (p<0.05). VMAT plans 
      performed better sparing for brain stem than dynamic IMRT (p=0.01). There was a 
      remarkable decrease in the maximum doses of VMAT to the eye. CONCLUSIONS: VMAT 
      outperforms dynamic IMRT by effectively reducing the MU and the dose to some 
      OARs, with adequate PTV coverage. Also, VMAT provides better sparing of normal 
      tissue and conformity than step-and-shoot IMRT. Differences between 
      step-and-shoot IMRT and dynamic IMRT are thought to be due to technical 
      differences of linear accelerator devices like fiber size, variable fiber, dose 
      rate and gantry.
FAU - Ozdemir, Sevim
AU  - Ozdemir S
AD  - Cerrahpasa Medical Faculty, Department of Radiation Oncology, Istanbul, Turkey.
FAU - Coban, Yasin
AU  - Coban Y
FAU - Akin, Mustafa
AU  - Akin M
FAU - Ambarcioglu, Pinar
AU  - Ambarcioglu P
FAU - Onay, Ozgehan
AU  - Onay O
FAU - Yildirim, Cumhur
AU  - Yildirim C
FAU - Uzel, Esengul
AU  - Uzel E
FAU - Uzel, Omer
AU  - Uzel O
LA  - eng
PT  - Journal Article
PL  - Cyprus
TA  - J BUON
JT  - Journal of B.U.ON. : official journal of the Balkan Union of Oncology
JID - 100883428
SB  - IM
MH  - Humans
MH  - Nasopharyngeal Neoplasms/*radiotherapy
MH  - Radiometry
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted
MH  - *Radiotherapy, Intensity-Modulated
EDAT- 2014/12/24 06:00
MHDA- 2018/06/23 06:00
CRDT- 2014/12/24 06:00
PHST- 2014/12/24 06:00 [entrez]
PHST- 2014/12/24 06:00 [pubmed]
PHST- 2018/06/23 06:00 [medline]
PST - ppublish
SO  - J BUON. 2014 Oct-Dec;19(4):953-7.