Conferences   /   OncoLink Scientific Meetings Coverage

Use of robots to improve patients' treatment and throughput

Reporter: Arpi Thukral, MD MPH
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 12, 2011

Presenter: Regis Ferrand
Presenter's Affiliation: Institut Curie-Centre de Protontherapie d'Orsay

Presentation/Overview

• The purpose of this presentation was to provide an overview of the 15-20 year history of the use of robotic couches at Institut Curie-Centre de Protontherapie d'Orsay (CPO).
• In the past 15 years, use of robotic positioning has developed tremendously in radiation therapy, particularly in particle therapy.
• The challenge of robotic positioning is that it must be fast and precise.
• Precise:
• Need 6 degrees of freedom, long range motion <0.5 mm, with smooth trajectories
• Need high repeatibility for QA checks and calibration
• Short range of motion: 0.2 mm
• Fast:
• Ability to load/unload patient
• Need to use a combination of fields
• Fast detection of unexpected motion
• Collision avoidance/back to safe position
• History of robots
• Before 1990: prototypes: MGH/HCL chair or eye chairs (CPO, PSI, MGH, Nice)
• 1995-2003 – 6 axis robot based (ex. MPRI)
• 2003-2009 – Scara-based, hexapode based
• 2010 – new hybrid designs (Poros PPS, Toshiba PPS)
• Extended use of robots besides patient postioning:
• Robotic CBCT
• MPRI snouth changer
• Trolleys (PSI, automated in Essen)
• Use of robots to calibrate devices inside the treatment room
• Chair and couch
• The CPO modest experience of 20 years:
• The CPO has been working on 4 different robots since 1990. These include:
• Hexapodes (original in 1991 and new version in 2006)
• accuracy <0.2 mm with limited range through +/- 10 degrees
• 2006 version has 360 degree vertical rotation
• not ideal for long range motion
• 6 axis based (1995)
• accuracy approx 3 mm
• The biggest advantage of this type is repeatibility.
• Scara based (Forte/Procure)
• Approx 0.5 mm precision
• New pit free prototype
• Developed within the frame of a research project.
• Specific architecture
• Intrinisic high precision (+/- 0.5 mm accuracy over long range movements)
• Ability to align patient inside and outside room
• Water tank permanently ready to use
• Lessons learned from 20 year experience at CPO:
• Except for hexapode, the intrinsic precision is NOT sufficient
• Calibration is mandatory and takes time.
• Robot has high potential and is designed for guidance.
• Has incredible robustness (only 3 problems in 15 years at CPO, likely due to neutrons)
• Future directions/concepts:
• New robotic concepts: (ex. Poros prototype, patented):
• Increased working envelope
• Intrinsic precision enhanced
• Reduced cycle (20 ms) – dynamic motion
• Hardware redundant saftely systems
• Fluid process
• Natural ability for: alignment inside/outside and adaptive therapy
• Simultaneous multi-PAS guidance
• Definition of true postioning strategy at the OIS level.

Author's Conclusions

• To compare proton and proton treatment, we need to dramatically improve the treatment process for protons (and not only the beam).
• Robotic patient positioners have proven their potential to play a key role in this process.
• However, there are still many advances that need to be made in this field for proton therapy.

Clinical Implications

• The author of this presentation clearly highlighted the history and advances made in the last 2 decades regarding the use of robotic technology to improve patient treatment and throughput in the proton arena.
• Robots play a key role in patient positioning, which in turn translates to greater efficiency in patient throughput.
• From this overview, we are able to assess the value and limitations of robotic patient positioning. This will help guide the development of future robotic technology for particle therapy.
• Future studies may focus not only on improving this technology, but also advancing it in terms of image guidance, safety and dynamic motion.
• Furthermore, efforts to adapt a global positioning process to specific clinical protocols are underway.