PMID- 12132939
OWN - NLM
STAT- MEDLINE
DCOM- 20020829
LR  - 20200219
IS  - 1526-9914 (Electronic)
IS  - 1526-9914 (Linking)
VI  - 3
IP  - 3
DP  - 2002 Summer
TI  - PTV margin determination in conformal SRT of intracranial lesions.
PG  - 176-89
AB  - The planning target volume (PTV) includes the clinical target volume (CTV) to be 
      irradiated and a margin to account for uncertainties in the treatment process. 
      Uncertainties in miniature multileaf collimator (mMLC) leaf positioning, CT 
      scanner spatial localization, CT-MRI image fusion spatial localization, and 
      Gill-Thomas-Cosman (GTC) relocatable head frame repositioning were quantified for 
      the purpose of determining a minimum PTV margin that still delivers a 
      satisfactory CTV dose. The measured uncertainties were then incorporated into a 
      simple Monte Carlo calculation for evaluation of various margin and fraction 
      combinations. Satisfactory CTV dosimetric criteria were selected to be a minimum 
      CTV dose of 95% of the PTV dose and at least 95% of the CTV receiving 100% of the 
      PTV dose. The measured uncertainties were assumed to be Gaussian distributions. 
      Systematic errors were added linearly and random errors were added in quadrature 
      assuming no correlation to arrive at the total combined error. The Monte Carlo 
      simulation written for this work examined the distribution of cumulative dose 
      volume histograms for a large patient population using various margin and 
      fraction combinations to determine the smallest margin required to meet the 
      established criteria. The program examined 5 and 30 fraction treatments, since 
      those are the only fractionation schemes currently used at our institution. The 
      fractionation schemes were evaluated using no margin, a margin of just the 
      systematic component of the total uncertainty, and a margin of the systematic 
      component plus one standard deviation of the total uncertainty. It was concluded 
      that (i) a margin of the systematic error plus one standard deviation of the 
      total uncertainty is the smallest PTV margin necessary to achieve the established 
      CTV dose criteria, and (ii) it is necessary to determine the uncertainties 
      introduced by the specific equipment and procedures used at each institution 
      since the uncertainties may vary among locations.
FAU - Parker, Brent C
AU  - Parker BC
AD  - Department of Radiation Physics, The University of Texas M. D. Anderson Cancer 
      Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA. 
      bparker@mdanderson.org
FAU - Shiu, Almon S
AU  - Shiu AS
FAU - Maor, Moshe H
AU  - Maor MH
FAU - Lang, Frederick F
AU  - Lang FF
FAU - Liu, H Helen
AU  - Liu HH
FAU - White, R Allen
AU  - White RA
FAU - Antolak, John A
AU  - Antolak JA
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Appl Clin Med Phys
JT  - Journal of applied clinical medical physics
JID - 101089176
SB  - IM
MH  - Brain Neoplasms/*radiotherapy
MH  - Computer Simulation
MH  - Dose Fractionation, Radiation
MH  - Humans
MH  - Magnetic Resonance Imaging/instrumentation/methods
MH  - Monte Carlo Method
MH  - Phantoms, Imaging
MH  - Radiotherapy Dosage/standards
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Radiotherapy, Conformal/instrumentation/*methods
MH  - Reproducibility of Results
MH  - Software
MH  - Tomography, X-Ray Computed/instrumentation/methods
PMC - PMC5724599
EDAT- 2002/07/23 10:00
MHDA- 2002/08/30 10:01
PMCR- 2002/06/01
CRDT- 2002/07/23 10:00
PHST- 2001/10/15 00:00 [received]
PHST- 2002/02/26 00:00 [accepted]
PHST- 2002/07/23 10:00 [pubmed]
PHST- 2002/08/30 10:01 [medline]
PHST- 2002/07/23 10:00 [entrez]
PHST- 2002/06/01 00:00 [pmc-release]
AID - ACM20176 [pii]
AID - 10.1120/jacmp.v3i3.2561 [doi]
PST - ppublish
SO  - J Appl Clin Med Phys. 2002 Summer;3(3):176-89. doi: 10.1120/jacmp.v3i3.2561.