PMID- 19920309
OWN - NLM
STAT- MEDLINE
DCOM- 20100219
LR  - 20091120
IS  - 1361-6560 (Electronic)
IS  - 0031-9155 (Linking)
VI  - 54
IP  - 23
DP  - 2009 Dec 7
TI  - Comparison of IMRT planning with two-step and one-step optimization: a strategy 
      for improving therapeutic gain and reducing the integral dose.
PG  - 7183-98
LID - 10.1088/0031-9155/54/23/010 [doi]
AB  - The aim of this study was to evaluate the effectiveness and efficiency in inverse 
      IMRT planning of one-step optimization with the step-and-shoot (SS) technique as 
      compared to traditional two-step optimization using the sliding windows (SW) 
      technique. The Pinnacle IMRT TPS allows both one-step and two-step approaches. 
      The same beam setup for five head-and-neck tumor patients and dose-volume 
      constraints were applied for all optimization methods. Two-step plans were 
      produced converting the ideal fluence with or without a smoothing filter into the 
      SW sequence. One-step plans, based on direct machine parameter optimization 
      (DMPO), had the maximum number of segments per beam set at 8, 10, 12, producing a 
      directly deliverable sequence. Moreover, the plans were generated whether a 
      split-beam was used or not. Total monitor units (MUs), overall treatment time, 
      cost function and dose-volume histograms (DVHs) were estimated for each plan. PTV 
      conformality and homogeneity indexes and normal tissue complication probability 
      (NTCP) that are the basis for improving therapeutic gain, as well as non-tumor 
      integral dose (NTID), were evaluated. A two-sided t-test was used to compare 
      quantitative variables. All plans showed similar target coverage. Compared to 
      two-step SW optimization, the DMPO-SS plans resulted in lower MUs (20%), NTID 
      (4%) as well as NTCP values. Differences of about 15-20% in the treatment 
      delivery time were registered. DMPO generates less complex plans with identical 
      PTV coverage, providing lower NTCP and NTID, which is expected to reduce the risk 
      of secondary cancer. It is an effective and efficient method and, if available, 
      it should be favored over the two-step IMRT planning.
FAU - Abate, A
AU  - Abate A
AD  - Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer 
      Institute, Rome, Italy.
FAU - Pressello, M C
AU  - Pressello MC
FAU - Benassi, M
AU  - Benassi M
FAU - Strigari, L
AU  - Strigari L
LA  - eng
PT  - Comparative Study
PT  - Journal Article
DEP - 20091117
PL  - England
TA  - Phys Med Biol
JT  - Physics in medicine and biology
JID - 0401220
SB  - IM
MH  - Head and Neck Neoplasms/radiotherapy
MH  - Humans
MH  - Probability
MH  - *Radiation Dosage
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Radiotherapy, Intensity-Modulated/adverse effects/*methods
MH  - Time Factors
EDAT- 2009/11/19 06:00
MHDA- 2010/02/20 06:00
CRDT- 2009/11/19 06:00
PHST- 2009/11/19 06:00 [entrez]
PHST- 2009/11/19 06:00 [pubmed]
PHST- 2010/02/20 06:00 [medline]
AID - S0031-9155(09)26442-6 [pii]
AID - 10.1088/0031-9155/54/23/010 [doi]
PST - ppublish
SO  - Phys Med Biol. 2009 Dec 7;54(23):7183-98. doi: 10.1088/0031-9155/54/23/010. Epub 
      2009 Nov 17.