title: IGRT/ART phantom with programmable independent rib cage and tumor motion.
abstract: OBJECTIVE
  This paper describes the design and experimental evaluation of the Methods and Advanced Equipment for Simulation and Treatment in Radiation Oncology (MAESTRO) thorax phantom, a new anthropomorphic moving ribcage combined with a 3D tumor positioning system to move target inserts within static lungs.
  
  
  METHODS
  The new rib cage design is described and its motion is evaluated using Vicon Nexus, a commercial 3D motion tracking system. CT studies at inhale and exhale position are used to study the effect of rib motion and tissue equivalence.
  
  
  RESULTS
  The 3D target positioning system and the rib cage have millimetre accuracy. Each axis of motion can reproduce given trajectories from files or individually programmed sinusoidal motion in terms of amplitude, period, and phase shift. The maximum rib motion ranges from 7 to 20 mm SI and from 0.3 to 3.7 mm AP with LR motion less than 1 mm. The repeatability between cycles is within 0.16 mm root mean square error. The agreement between CT electron and mass density for skin, ribcage, spine hard and inner bone as well as cartilage is within 3%.
  
  
  CONCLUSIONS
  The MAESTRO phantom is a useful research tool that produces programmable 3D rib motions which can be synchronized with 3D internal target motion. The easily accessible static lungs enable the use of a wide range of inserts or can be filled with lung tissue equivalent and deformed using the target motion system.
authors: Control Theory and Applications Centre, Coventry University, Coventry CV1 2TL, United Kingdom.
authors: Olivier C L
authors: OC
authors: Haas
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: John A
authors: JA
authors: Mills
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: Imke
authors: I
authors: Land
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: Pete
authors: P
authors: Mulholl
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: Paul
authors: P
authors: Menary
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: Robert
authors: R
authors: Crichton
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: Adrian
authors: A
authors: Wilson
authors: Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX, United Kingdom.
authors: John
authors: J
authors: Sage
authors: University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary, Leicester, LE1 5WW, United Kingdom.
authors: Morenc
authors: M
authors: Anna
authors: Radiotherapy, Medical Physics Group, University Hospital UZ Brussel, Laarbeeklaan 101 - 1090 Brussels, Belgium.
authors: Tom
authors: T
authors: Depuydt
mesh_terms: D008175:Lung Neoplasms / Q000503:physiopathology* / Q000532:radiotherapy*; D009068:Movement; D019047:Phantoms, Imaging; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation*; D012272:Ribs / Q000502:physiology*